?,EPA
United States
Environmental Protection
Agency
Proceedings
Nanotechnology an<3 the Environment;
Applications and Implications
Progress Review Workshop III
October 26-28^ 2005
Arlington, VA
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n
Proceedings
Nanotechnology and the Environment:
Applications and Implications
Progress Review Workshop III
October 26-28, 2005
Arlington, VA
U.S. Environmental Protection Agency
Office of Research and Development
Washington, DC 20460
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Table of Contents
Introduction ,..... „„, vi
U s EPA Headquarters library
Executive Summary •••"••••••|^|-eoUe-3-*34T 1
Section i. Aerosols 1200 Pennsylvania Avenue, NW
Washington DC 20460
Abstract: Elemental Composition of Freshly Nucleated Particles 2Q2-566-055§ 30
Murray V. Johnston
Abstract: Ion-Induced Nucleation of Atmospheric Aerosols 31
Peter H. McMurry, Fred Eisele
Section!. Life-Cycle Analysis
Abstract: Evaluating the Impacts of Nanotechnology via Thermodynamic and Life-Cycle Analysis 33
Bhavik R, Bakshi
Section 3. Green Manufacturing
Abstract: Development ofNanocrystalline Zeolite Materials as Environmental Catalysts 35
Sarah Larsen
Environmental Implication/Application: Development ofNanocrystalline Zeolite Materials as
Environmental Catalysts ". 36
Sarah Larsen
Abstract: Ecocomposites Reinforced With Cellulose Nanoparticles: An Alternative to Existing
Petroleum-Based Polymer Composites 37
William T. Winter
Abstract: Nanostructured Microemulsions as Alternative Solvents to VOCs in Cleaning Technologies
and Vegetable Oil Extraction 38
David Sabatini, Anuradee Witthayapanyanon, Linh Do
Success Stories 40
Section 4. Remediation
Abstract: Dendritic Nanoscale Chelating Agents: Synthesis, Characterization, Modeling and
Environmental Applications 43
Mamadou S. Diallo, Lajos Balogh, William A. GoddardlH, James H. Johnson, Jr.
Abstract: Delivering Functional Fe(0)-Based Nanoparticles for In Situ Degradation of DNAPL
Chlorinated Organic Solvents 44
Gregory V. Lowry, Bruno Dufour, Yueqiang Liu, Sara A. Majetich, Kris Matyjaszewski,
Tanapon Phenrat, Navid Saleh, Kevin Sirk, Robert D. Tilton
Success Stories 48
Abstract: Nanostructured Catalytic Materials forNOx Reduction Using Combinatorial Methodologies 49
Selim Senkan
Abstract: A Bioengineering Approach to Nanoparticle-Based Environmental Remediation 50
Daniel Strongin
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Abstract: Nanoscale Bimetallic Particle for In Situ Remediation 51
Wei-xian Zhang
Abstract: Nanostructured Catalysts for Environmental Remediation of Chlorinated Compounds 52
Yunfeng Lu, Vijay T. John
Environmental Implication/Application: Nanostructured Catalysts for Environmental Remediation 55
of Chlorinated Compounds
Yunfeng Lu, Vijay T. John
Abstract: Synthesis and Application of a New Class of Stabilized Nanoscale Iron Particles for
Rapid Destruction of Chlorinated Hydrocarbons in Soil and Groundwater 57
Dongye Zhao
Section 5. Sensors
Abstract: Metal Biosensors: Development and Environmental Testing 59
Anne Anderson, Charles Miller, Joan McLean
Abstract: Nanosensors for Detection of Aquatic Toxins 60
Robert E. Gawley
Abstract: Neuromorphic Approach to Molecular Sensing With Chemoreceptive Neuron MOS
Transistors (CvMOS) 61
Edwin C. Kan, Bradley A. Minch
Abstract: Compound Specific Imprinted Nanospheres for Optical Sensing 62
Barry K. Lavine
Abstract: Advanced Nanosensors for Continuous Monitoring of Heavy Metals 63
OmowumniA. Sadik, Joseph Wang, Ashok Mulchandani, Issac Kawino, Jason Karasinki,
Marcells Omole, Daniel Andreescu
Abstract: Ultrasensitive Pathogen Quantification in Drinking Water Using High Piezoelectric
PMN-PT Microcantilevers 64
Wan Y. Shih, Wei-HengShih
Abstract: Low-Cost Organic Gas Sensors on Plastic for Distributed Environmental Monitoring 65
Vivek Subramanian
Abstract: A Nanocontact Senfor for Heavy Metal Ion Detection 66
Nongjian Too
Abstract: Nanomaterial-Based Microchip Assays for Continuous Environmental Monitoring 68
Joseph Wang
Abstract: Conducting-Polymer Nanowire Immunosensors Array for Microbial Pathogens 69
Ashok Mulchandani
Abstract: Exploring the Impact of a Nanostructure's Size and Shape on Cellular Uptake, Clearance,
and Metabolism 70
Warren Chan
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Section 6. Treatment
Abstract: Applications ofNanoscale Tunable Biopolymers for Heavy Metal Remediation 72
Ashok Mulchandani
Abstract: Synthesis, Characterization, and Catalytic Studies of Transition Metal Carbide Nanoparticles
as Environmental Nanocatalysts 73
S. Ismat Shah
Abstract: A Novel Approach To Prevent Biocide Leaching 75
Patricia Heiden, Laurent Matuana, Ben Dawson-Andoh
Environmental Implication/Application: A Novel Approach To Prevent Biocide Leaching 77
Patricia Heiden, Laurent Matuana, Ben Dawson-Andoh
Section 7. Fate/Transport
Abstract: Chemical and Biological Behavior of Carbon Nanotubes in Estuarine Sedimentary Systems 80
P. Lee Ferguson
Abstract: A Focus on Nanoparticulate Aerosol and Atmospherically Processed Nanoparticulate Aerosol 81
Yield H. Grassian
Abstract: Transformations of Biologically Conjugated CdSe Quantum Dots Released Into Water
and Biofilms 82
Patricia A. Holden, Jay Nadeau
Abstract: Absorption and Release of Contaminants Onto Engineered Nanoparticles 84
Mason Tomson
Abstract: Fate and Transport of C60Nanoparticles in Unsaturated and Saturated Soils 86
Kurt D. Pennell
i
Abstract: Cross-Media Transport, Transformation, and Fate of Carbonaceous Nanomaterials 87
Linsey C. Marr
Sections. Toxicity
Abstract: Short-Term Chronic Toxicity of Photocatalytic Nanoparticles to Bacteria, Algae,
and Zooplankton .- 89
Chin-Pao Huang
Abstract: Physical and Chemical Determinants of Nanofiber/Nanotube Toxicity 90
Robert Hurt, Agnes Kane
Success Stories : 90
Abstract: The Fate, Transport, Transformation, and Toxicity of Manufactured Responses of Lung Cells
to Metals in Manufactured Nanoparticles 91
JohnM. Veranth, Christopher A. Reilly, GaroldS. Yost
Abstract: Nanomaterials in Drinking Water 93
Paul Westerhoff
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Abstract: Microbial Impacts of Engineered Nanoparticles.... 94
Pedro J.J. Alvarez, Mark R. Wiesner
Abstract: Semiconductor Nanowires and Applications to Human Health 95
Ray LaPierre
Abstract: Interactions Between Semiconductor Nanoparticles and Biomembranes and DNA , 96
Jay Nadeau
Environmental Implication/Application: Interactions Between Semiconductor Nanoparticles and
Biomembranes and DNA , .98
Jay Nadeau
Abstract: Understanding the Light-Induced Cytotoxicity of Quantum Dots: A Cellular, Photophysical,
and Mechanistic Approach 99
Francoise Winnik
Section 9. Exposure
Abstract: Nanomaterial Interactions With Skin 101
Nancy A. Monteiro-Riviere, Jim E. Riviere
Abstract: Repercussion of Carbon-Based Manufactured Nanoparticles on Microbial Processes in
Environmental Systems 104
Ronald F. Turco, Bruce M. Applegate, Timothy Filley
Abstract: Iron Oxide Nanoparticle-Induced Oxidative Stress and Inflammation 105
Alison C.P. Elder, Hong Yang, Jack Finkelstein, Gunter Oberddrster
Abstract: Effects of Nanomaterials on Human Blood Coagulation 109
Peter L, Perrotta, Pelagia-Irene Gouma
Abstract: Assessment Methods for Nanoparticles in the Workplace 110
Patrick T.O'Shaughnessy
Appendix
Agenda 112
Participants List 119
Index of Speakers, Authors, and Co-Authors 125
Cover Image: Copyright. Dr. V.H. Crespi, Penn State University. Distributed under the Open Content License
(http:^opencontent.org/opl/shtml).
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Introduction
Nanoscale science, engineering, and technology incorporate a variety of disciplines, including chemistry, ma-
terials science, biology, engineering, electronics, and physics. The term nanotechnologies refers to technolo-
gies in the range of 1-100 nanometers and to the ability to work at the molecular level, atom by atom, to create
large structures with fundamentally new molecular organization. There is a potential for truly revolutionary
transformative capabilities for an entire host of products and processes, including those that enhance environ-
mental quality and sustainability through pollution prevention, treatment, and remediation. The potential also
exists for adverse effects on human health and the environment. Understanding and preventing or mitigating
these effects is vital both for the responsible development of the technology and for the U.S. Environmental
Protection Agency (EPA) to carry out its mission.
EPA's Office of Research and Development (ORD), National Center for Environmental Research (NCER), as
part of its Science To Achieve Results (STAR) program, supports research leading to applications of nano-
technology. EPA is interested in advances in nanotechnology that can improve the protection of human health
and the environment, including significant improvements in cost or performance to assess and solve environ-
mental problems. In anticipation of the significant impacts resulting from the development of nanotechnology,
EPA is engaging in a variety of activities, including sponsoring research and development on the potential en-
vironmental applications and implications of nanotechnology, developing a White Paper outlining Agency pri-
orities and needs, coordinating extramural and intramural nanotechnology research, coordinating and partici-
pating in strategic research planning concerning the potential role(s) for emerging technologies with respect to
environmental protection, and providing information at a variety of conferences and workshops composed of
academic, industry, government, and non-governmental organization (NGO) representatives dealing with pos-
sible societal and environmental impacts of novel technologies.
Nanotechnology offers an opportunity to significantly impact environmental sensing research needs. For ex-
ample, nanotechnology makes it possible to develop parallel arrays of nanoscale sensor elements, which would
result in increased sensitivity, accuracy, and spatial resolution in the simultaneous detection of a large number
of compounds. Most sensors depend on interactions occurring at the molecular level; hence, nanotechnology-
enabled sensors can have a tremendous effect on our capacity to monitor and protect the environment.
Nanotechnology is certain to improve existing sensors and benefit the development of new ones. However,
there are many challenges such as reducing the cost of materials and devices, while improving accuracy and
sensitivity, and delivering the compound to the device when working with very dilute concentrations.
Treatment and remediation techniques also can be greatly improved through nanotechnology. The potential
exists to develop inexpensive remediation and treatment technologies that enable the rapid and effective
cleanup of recalcitrant compounds, especially those located in inaccessible areas. Currently, many of the meth-
ods that the Agency employs to remove toxic contaminants from the environment involve laborious, time-
consuming, and expensive techniques. Such techniques often require pretreatment processes and removal of
portions of the surrounding environment with the consequent disturbance of the ecosystem. The development
of technologies that can perform in situ-and that are able to reach into crevices, below aquifers, and other diffi-
cult areas, eliminating the necessity for costly pump-and-treat operations, would greatly facilitate the remedia-
tion of many contaminated sites, especially those contained on the Superfund list. Current challenges include
the need to increase the stability of nanoparticles utilized in remediation/treatment methodologies, the need to
develop manufacturing techniques for the mass production of these materials, and the need to develop im-
proved methods for monitoring the fate and transport of these materials once they enter the natural environ-
ment.
Environmentally benign manufacturing and processing methods enabled by nanotechnological advances will
result in the elimination of toxic wastes and by-products and facilitate bottom-up chemical and industrial
manufacturing that utilizes "green" processes. Such "green" or environmentally benign manufacturing proc-
esses will not only eliminate waste streams (via precise manufacturing) as a resultant product, but also will
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Nanatechnology and the Environment: Applications and Implications Progress Review Workshop HI
reduce the risks associated with the use of hazardous reactants and solvents through the use of nonhazardous
starting materials. These processes also have the potential to significantly reduce the consumption of energy
and to make many of the alternative clean energy sources (e.g., solar, fuel cells) commercially viable. Chal-
lenges to the development and adoption of these processes include the need to develop mass manufacturing
techniques and the need to educate industry concerning their potential applicability.
NCER also supports research through STAR grants in understanding the implications of nanotechnologics.
There is a serious lack of information about the human health and environmental implications of manufactured
nanomaterials (e.g., nanoparticles, nanotubes, nanowires, fullerene derivatives, quantum dots, dendrimers, and
other nanoscale materials). Potentially harmful effects of nanotechnology might arise as a result of the nature
of the nanoparticles themselves, the characteristics of the products made from them, aspects of the manufactur-
ing process involved, and the use of the products or the end-of-life disposal. The large surface area, crystalline
structure, type and degree of functionalization, and reactivity of some nanoparticles may facilitate transport in
the environment or lead to harm because of their interactions with cellular materials. Because size matters on
the nanoscale, harmful effects caused by the composition of the material itself could be increased.
EPA's research concerning environmental implications examines the potential persistence and possible syner-
gistic effects of nanomaterials with other contaminants or naturally occurring compounds in the environment.
Reactivity and the types of compounds that result are crucial degradation questions. There also is the issue of
the potential bioavailability, bioaccumulation, and biotransformation capacities of nanomaterials. The capacity
of these materials to accumulate in certain nanoparts of living systems in various species must be explored,
along with the metabolic and alteration of these materials and their subsequent effects on living systems.
Knowledge about the transport of nanomaterials that reach the environment is important and is currently un-
known. How these materials move from one media to another, from one organism or ecosystem to another, and
from organisms to the environment and vice versa will be critical for understanding and implementing proper
manufacture, use, and end-of-life options. To effectively assess these impacts, a full life-cycle analysis of the
materials and products must be undertaken—from starting materials to the manufacture, use, and eventual dis-
posal or reuse.
EPA-sponsored nanotechnology research outlined in this document addresses these challenges and concerns.
Researchers in the areas of environmental applications and implications of nanotechnology presented data and
results from their work, some of which began in 2002. This Progress Review Workshop brings together EPA's
extramural scientists as well as scientists and policymakers from government, academia, and NGOs, with rep-
resentatives from Canada and Europe to consider both the environmental applications and implications of
nanotechnology.
The research described in this report has not been subjected to the Agency's required peer review and policy
reviews, and does not necessarily reflect the views of the Agency. Therefore, no official endorsement should
be inferred. Any opinions, findings, conclusions, or recommendations expressed in this report are those of the
investigators who participated in the research or others participating in the Progress Review Workshop, and
not necessarily those of EPA or the other federal agencies supporting the research.
For more information on EPA's nanotechnology research, please contact Barbara Karn, Ph.D., at 202-343-
9704 (karn.barbara@epa.gov); or Nora Savage, Ph.D., at 202-343-9858 (savage.nora@epa.gov).
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
U.S. EPA 2005 Nanotechnology Science To Achieve Results (STAR)
Progress Review Workshop—Nanotechnology and the Environment III:
Applications and Implications
Holiday Inn Rosslyn at Key Bridge
1900 N. Fort Myer Drive
Arlington, VA 22209
October 26 - 28, 2005
Executive Summary
OVERVIEW
The U.S. Environmental Protection Agency's (EPA) 2005 Nanotechnology Science To Achieve Results
(STAR) Progress Review Workshop—Nanotechnology and the Environment III: Applications and Im-
plications was held on October 26-28, 2005, in Arlington, Virginia. The workshop brought together
approximately 150 researchers from academia and government to discuss ongoing research on nano-
technology and the environment. The focus for this year's meeting was applications and implications of
nanotechnology. The workshop served as a stimulus for increased collaborations among the various
researchers and included information to provide knowledge in the area of international nanotechnology
research support.
Welcome and Introductory Remarks
William Farland, U.S. EPA
Dr. Farland noted that this workshop provides an important opportunity for EPA staff to interact with
grantees and the academic community focusing on environmental applications and implications of nano-
technology. The workshop goals are to provide a stimulus for increased collaborations among the various
researchers, improve knowledge of the environmental aspects of nanotechnology, and identify future
research needs. EPA's role is to provide leadership on environmental applications and implications of
nanotechnology.
The challenge is to identify how nanoscience can be used for beneficial environmental applications as
well as to understand and predict the human health and ecological implications of nanoparticle releases to
the environment. Nanotechnology applications can address existing environmental problems .and prevent
future problems in the areas of air and water quality, reduction of toxic compounds, and improved home-
land security. Implications research is needed to assess nanomaterials in the environment and any possible
risks that may be posed by nanotechnology. EPA has funded STAR nanotechnology research grants since
2001, beginning with applications and now focusing on implications. The newest request for STAR
applications on nanomaterials is a joint release with the National Science Foundation (NSF), the National
Institute of Environmental Health Sciences (NIEHS), and the National Institute for Occupational Safety
and Health (NIOSH).
EPA faces regulatory challenges in the area of nanotechnology. The Agency is integrating its own science
needs with those of other regulatory agencies through the Nanoscale Science, Engineering and
Technology (NSET) Nanotechnology Environmental Health and Implications Workgroup. In EPA's first
action related to nanomaterials, the Office of Pollution Prevention and Toxics has "permitted limited
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
manufacture" under the Toxics Substances Control Act (TSCA) of a nanomaterial. More of these actions
are likely to occur in the next few years.
PLENARY TALKS
Towards a National Nanotechnology Strategy for Canada
Paul Dufour, Privy Council Office, Government of Canada
The Canadian government has been investing heavily in overall research spending and has the highest per
capita investment within the G-8 for support of the university research and research institutes. Investment
specifically targeted to nanotechnology research is growing. Provincial governments in Canada also are
supporting the development and commercialization of nanotechnology. NanoQue"bec, which provides
structuring and planning efforts in nanotechnology in Quebec, is one example of the provincial Canadian
focus on nanotechnology. Canada is working on a national nanotechnology strategy that will include
research and development, innovation and commercialization, regulatory considerations, and education
and engagement with the public. Regulations are an emerging issue, and a life cycle approach is needed
as a guideline for. assessing regulatory needs for the environmental management of nanotechnology.
Sustained investments are necessary but will not be effective without a strategy that is national in scope,
integrated, multidisciplinary, and internationally linked. Environmental, health, societal, and ethical
issues associated with nanotechnology will be a core element of the Canadian strategy.
The strengths of the Canadian effort include talent in areas such as quantum computing and quantum
devices, lab-on-a-chip and biodiagnostic devices, materials self-assembly, nanophotonics, and instrument
development. Canadian universities and the Canadian National Research Council conduct leading-edge
research, and the country has expertise in environment, agriculture, manufacturing, health, energy,
communications, and security industries, which are prime areas of nanotechnology opportunities. Oppor-
tunities exist to collaborate with EPA, and Canada is pleased to work with the United States in the area of
nanotechnology.
National Nanotechnology Initiative: The Long-Term View
Mihail Roco, NSF
The National Nanotechnology Initiative's (NNI) long-term vision is that the systematic control of matter
on the nanoscale level will lead to a revolution in technology and industry. The NNI definition of nano-
technology involves technology that meets three criteria: (1) research and technology development at the
atomic, molecular, or macromolecular levels, in the length scale of approximately 1 to 100 nanometer
range; (2) creation and use of structures, devices, and systems that have novel properties and functions
because of their small and/or intermediate size; and (3) the ability to control or manipulate matter on the
atomic scale. Four generations of nanostructures are predicted: passive nanostructures (already in exis-
tence), active nanostructures (active research and development presently in process), systems of nano-
systems (by 2010), and molecular nanosystems (by 2015). The NSET Subcommittee of the National
Science and Technology Council coordinates, plans, and implements the NNI, which has a current year
funding of approximately $1 billion.
From 2001-2005, the elements of NNI included: funding fundamental research activities, examining long-
term challenges, establishing centers and networks of excellence, developing a research infrastructure,
beginning to address societal implications, and workforce education and training needs. Accomplishments
include more than 3,000 active projects, more than 50 large nanotechnology research centers and
networks, and education and outreach that began at the graduate education level and is expanding to the
undergraduate and high school level, as well as K-12 informal science education.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Collaborations and partnering are important. International dialogue on responsible nanotechnology re-
search and development has begun through workshops and workgroups. In addition, for the immediate
and continuing societal implications issues, long-term concerns must be addressed. An anticipatory and
corrective approach in planning is needed that is both transforming and responsible in addressing societal
implications for each major nanotechnology research and development program or project from the
beginning. Risk governance of nanotechnology is becoming an increasing focus at the national and
international levels.
An Overview of Canadian Nanomedicine Research Funding: The Canadian Institute
of Health Research Vision
Eric Marcotte, Canadian Institute of Health Research
)
The Canadian Institute of Health Research (C1HR) is a virtual organization with networks of researchers
aligned along common interests and themes. CIHR scientific directors remain at their host universities
and collectively advise the Canadian Governing Council on research plans and budget allocations to
support'cross-disciplinary, internationally competitive health research in Canada. The Regenerative
Medicine and Nanomedicine Initiative is one of three major strategic initiatives of CIHR and is co-led by
the Institute of Neurosciences, Mental Health, and Addiction and the Institute of Genetics. Regenerative
medicine and nanomedicine were combined because of similar research interests and allows for more
funding options. Research topics include: nanotechnology gene therapy; stem cells; tissue engineering;
rehabilitation sciences; and social, ethical, economic, environmental, and legal issues.
Dr. Marcotte highlighted two examples of research funded through the Regenerative Medicine and
Nanomedicine Initiative. The first is a research project of Dr. Isabelle Brunette at Hopital .Maisonneuve-
Rosemont that focuses on improved outcomes of corneal transplantation using femtosecond laser-assisted
corneal posterior lameller transplantation with endolethelial enhancement. The second example is
research in Dr. Warren Chan's laboratory at the University of Toronto on the use of quantum dots in
tissue remodeling, early cancer diagnosis, and guidance during tumor detection with potential
applications in stem cell research. Sixty percent of new discoveries from grants have been for
nanomedicine projects. The nanomedicine grants and projects are in the following categories: drug
delivery, biomaterials, clinical imaging/tools, and molecular imaging/tools. Funding has been increasing
for nanomedicine projects. A new 2005 request for applications includes a call for projects that address
the health, safety, and environmental risks of nanomedicine. CHIR strengths include strong ongoing
funding support for nanomedicine, a commitment to multidisciplinary research, and close interagency
collaboration.
Nanotechnology at EPA—An Update
Barbara Karn, U.S. EPA, on detail at Woodrow Wilson Center
EPA's research framework for nanotechnology and the environment involves applications and impli-
cations. Applications address existing environmental problems or prevent future problems. Implications
address the interactions of nanomaterial with the environment and any possible risks that may be posed
by nanotechnology. EPA's nanotechnology research program has six thrusts: (1) build and sustain a com-
munity of researchers in nanotechnology and the environment, including both applications and impli-
cations; (2) institutionalize nanotechnology within EPA's mission; (3) assure consideration of the
environment and human health in governmental research programs related to nanotechnology; (4) work
with industry to assure environmentally responsible development of nanotechnology and products
containing nanomaterials; (5) provide leadership in international activities involving the environment,
human health, and nanotechnology; and (6) provide 'education and outreach to the public to promote
understanding of nanotechnology with respect to the environment and human health.
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Progress has been made in nanotoxicology research, the number of nanotechnology products available,
and the amount of research funding for nanotechnology and the environment issues. Improvement is still
needed in nanotechnology in sustainability research, life cycle studies, and public involvement. Dr. Kara
shared information on her work at the Woodrow Wilson Center on "green" nanotechnology to make
nanomaterials and nanoproducts "greenly" and to use nanotechnology to "green up" current processes.
The focus of "green" nanotechnology includes understanding of the full life cycle of nanomaterials and
nanoproducts, which is necessary for sustainabiiity. The challenge is to use nanotechnology to help clean
up past environmental damage, correct present environmental problems, prevent future environmental
impacts, and help sustain the planet for future generations.
Nanotech: Rolling to Market
David Rejeski, Woodrow Wilson Center
A survey by Small Times magazine identified more than 1,600 companies involved in nanotechnology,
with more than 700 products being produced, The question is how consumers will respond to nano-based
products. Companies do not always advertise their involvement in nanotechnology because industry is not
sure if nanotechnology is an asset or liability. Concerns exist over public reaction and governmental
regulations. Scientists focus on the health and environmental risks of nanotechnology, but investors focus
on consumer perception. Sixty to 70 percent of the public has never heard of nanotechnology. Once
informed, the public is excited about the benefits of nanotechnology, but trust in either industry or
government to manage nanotechnology risks is low, and gaps exist in the current regulatory system to
address nanotechnology risks.
The area of green nanotechnology (Green Nano) has large potential benefits with low perceptual risks.
Three areas include: "dark green"—nanotechnology applied directly to solve environmental problems;
"light green"—nanotechnology providing environmental benefits for other applications; and "right
green"—nano-based processes and products designed to have an environmentally low impact. Dr. Rejeski
proposed the following to support a U.S. green nano-based program: (1) create at least one dedicated
NSF/EPA-funded Center for Green Nano; (2) create a database of Green Nano research and researchers
and make it available for investors; (3) ensure technology verification for nano-based products; (4) utilize
a government procurement system to support Green Nano products on the market; and (5) focus Small
Business Innovation Research (SBIR) grants on Green Nano.
Nanotechnology and Human Health Impact
Andrew Maynard, Woodrow Wilson Center
Many societal and environmental benefits are anticipated from nanotechnology projects and products, but
there may be unanticipated roadblocks, including unexpected human health and environmental risks.
Sustainable nanotechnology will depend on societal acceptance, minimizing risk, and maximizing the
benefits of the technology. The foundation for a positive nanotechnology outcome is based on global
partnerships and moving beyond the hype and confusion of this technology. Global implications require
global cooperation and collaboration, including coordinated approaches to finding solutions.
Implications-focused research must be specific to materials, devices, and products. It is important .to
differentiate between nano-based materials and products presenting significant, marginal, or no potential
risk. Information is available using similarity, analogy, and principles from research in areas of aerosol
behavior, exposure control, general health effects, ultrafme hazards, and physicochemical significance of
specific products such as asbestos and crystalline silica. Extrapolation used wisely can provide strategic
direction. Integration of risk-based and applications-based research will be necessary to pre-empt and
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
proactively minimize adverse health impact. Characterization is important for risk assessment. The
complexity of many nanomaterials demands sophisticated characterization, frequently beyond what is
typically applied to "macro" materials. Understanding implications to human health will require multiple
disciplines working together.
Nanotechnology in the EU: Research Opportunities
Pilar Aguar, European Commission
This talk was focused on European health and safety nanotechnology research activities and noted that the
European Commission is interested in fostering international cooperation and collaborations. The goal of
the European approach is a European nanotechnology strategy that is integrated and responsible. The
Commission has supported research and development and increased support for collaborative research
and development into the potential impact of nanotechnology on human health and the environment.
NANOSAFE and NANOFORUM are two examples of previous European projects related to the safety of
nanoparticles. Current projects include NANOSAFE2, NANOTOX, and IMPART; these programs focus
on the interaction of engineered nanoparticles with the environment and the living world. The upcoming
program request includes a doubling of the overall budget with large increases proposed for nanosciences
and nanotechnologies, with an emphasis on collaborative research, frontier capacity, human potential, and
research capacity. The European Union's current Framework Programme for Research and Technological
Development (and presumably the upcoming one also) is open to the world, with funding granted to
participants from almost ail countries.
Natural Sciences and Engineering Research Council of Canada (NSERC) Nano Innovation Platform
Peter Grutter, National SERC Nano Innovation Platform
The NSERC Nano Innovation Platform (NanoIP) is a multidisciplinary, national network of university
researchers from many fields of science and engineering created to accelerate and intensify research and
education of high-quality personnel in nanoscience and nanotechnology in Canada. The objectives of
NanoIP are to: develop and implement a national strategy with stakeholders; facilitate and build local
nanotechnology communities; support a few high-risk projects at high funding levels; and increase the
budget for nanotechnology in Canada. NanoIP award selections are based on quality, innovation, and the
need for funds. An international refereeing and selection committee selects recipients. The overall goal is
for a better understanding of the basic physicochemical properties of nanomaterials and nanoparticles.
Fundamental understanding of nanomaterials is needed before toxicology and environmental studies can
be generalized. The NanoIP awards assist in providing the foundation to investigate nanomaterial and
nanoparticle toxicology and environmental and biological impact. A systematic coordinated approach is
necessary, as this task is complex, time consuming, and expensive.
Health Canada Overview: Foresight Activities
David Blakey, Health Canada
Health Canada is the federal department responsible for helping the people of Canada maintain and
improve their health. Its mission and activities are accomplished through partnerships. The existing tools
for managing the risks related to nanotechnology include legislation and regulation. There are policies
and guidelines that are under development and review. Life cycle management is needed to address the
various exposure potentials of nanotechnology. Research is needed on the toxicology of nanotechnology
as well as detection and monitoring tools. Gaps exist in the knowledge of toxicity and in vivo effects,
exposure routes, and bioaccumulation potential. EPA and Health Canada have a collaborative effort to
investigate the toxicological properties of metallic iron nanoparticles. Further discoveries and
understanding of fundamental properties of nanomatter hold promise for beneficial new materials and
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
applications; therefore, it is imperative to consider potential health effects to ensure that
commercialization of innovations occurs while minimizing risks and building public confidence and
acceptance. Risk research must be adequately funded, early in the process, and in balance with innovation
investments. International cooperation is important to address these needs.
International Aspects of Nanotechnology
Celia Merzbacher, Executive Office of the President
Nanotechnology research activities and funding amounts invested around the world are increasing.
Nanotechnology is advanced both through collaboration and healthy competition. Collaborations are in-
creasing through continued interaction, policies that support collaboration, educational programs, the
scientific need, and .ad vantages of collaboration.
The development of standards is an important international effort in nanotechnology. Standards can aid
research and development, support commerce and trade, and protect human health and the environment.
The United States sets standards differently than other countries. The National Technology Transfer and
Advancement Act of 1995 requires U.S. governmental agencies to use voluntary, consensus standards in
lieu of government-unique standards, except where it is inconsistent with law or impractical to
accomplish. The American National Standards Institute (ANSI) is the nonprofit organization that
administers and coordinates the U.S. voluntary standardization and conformity assessment system with a
mission to enhance the global competitiveness of U.S. business and improve the U.S. quality of life. The
ANSI Nanotechnology Standards Panel provides: a forum for interested parties to define needs; facilitates
development and adoption of standards responsive to identified needs; and acts as a liaison with other
national, regional, and international nanotechnology standards efforts to create identical, or harmonize
existing, standards.
International trade is an area that is now becoming a focus for nanotechnology. Preliminary discussions
on an international level relate to export control, the Wassenaar Agreement, and visas. The Organisation
of Economic Co-operation and Development (OECD) has nano-related activity, and these activities can
be influential in trade issues.
NIOSH Nanotechnology Research Program
Vladmir Murashov, NIOSH
The NIOSH Nanotechnology Initiative addresses the implications and applications of nanotechnology in
the workplace through a research program, a research center, and extramural program support. The
NIOSH Nanotechnology Safety and Health Research Program presently funds five nanotechnology
research projects. The NIOSH Nanotechnology Research Center is a virtual center that aims to identity
critical issues, develop a strategic plan to address issues, fund new nanotechnology projects, and
disseminate information gained. One focus for the center is the development of a Web-based nano-
information library (http://www.cdc.gov/niosh/topics/nanotech/NIL.html). In addition, NIOSH has
research supplement projects focusing on toxicity of nanoparticles as wel! as an extramural program that
funds nanotechnology research. NIOSH has partnered with EPA to fund projects related to occupational
health. Collaborative programs provide an opportunity to leverage resources, and NIOSH has established
a number of collaborative programs with a wide range of academic, industrial and government partners.
The outreach occurs through conferences, a Web site, current intelligence bulletins, and safety
recommendations. Dr. Murashov encouraged participants to sign up for Focus on Nanotechnology at
http.y/www.cdc.gov/niosh/topics/nanotech/focus.html, which highlights occupational and health
applications and implications research.
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NSF Perspective
Cynthia Ekstein, NSF
NSF is the principal source of federal funding for university-based fundamental engineering research,
providing more than 42 percent of the total federal support in this area. NSF supports fundamental
research on engineering systems, devices and materials, and their underpinning processes and
methodologies. Nanoscale engineering received the largest funding for NSF Engineering activities in
FY05. This funding supported four areas: Nanoscale Interdisciplinary Research Teams, Nanoscale
Science and Engineering Centers, nanoscale exploratory research, and nanotechnology undergraduate
education. Collaborative RFAs have been issued for nanotoxicology research with EPA, NIOSH, and
NIEHS. NSF recognizes the importance of an understanding of nanotechnology by the public and the
U.S. workforce. NSF has selected the University of California, Santa Barbara, and Arizona State
University to create two new Centers for Nanotechnology in Society. These centers will support research
and education on nanotechnology and social change, as well as educational and public outreach activities
and international collaborations.
REMARKS
Dr. Karn thanked participants for attending the workshop, particularly colleagues from Europe and
Canada. The workshop provided an opportunity to build the research community, allowing participants to
hear aspects of nanotechnology and the environment outside of their disciplines. EPA funds a broad range
of research projects in applications and implications, and meetings such as this workshop allow for
communication across a wide range of disciplines.
RESEARCH PROJECT PRESENTATIONS
AEROSOL
U.S. EPA STAR Grantees
Elemental Composition of Freshly Nucleated Particles
Murray Johnston, University of Delaware
The objective of this project is to develop a method for real-time sampling and analysis of individual
airborne nanoparticles in the 5 to 20 nm diameter range. Airborne particles are associated with societal
implications related to human health concerns and global climate change. Real-time single particle mass
spectrometry is used to measure ambient aerosol to determine the chemical composition of individual
particles as a function of particle size and to count particles as a function of size and composition. Laser-
induced plasma formation can determine the elemental composition of many particle types; the detection
efficiency is independent of particle size and composition. Fundamental limitations of nanoparticle trans-
mission contribute to sampling rate limitation because of aerodynamics and Brownian motion. Electro-
dynamic focusing, which requires particle charging as well as electrodynamic trapping to increase the
detection duty factor and overcome inefficient charging, may be used to help address these issues.
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LIFE-CYCLE ANALYSIS
U.S. EPA STAR Grantees
Evaluating the Impacts of Nanotechnology via Thermodynamic and Life-Cycle Analysis
Bhavik Bakshi, Ohio State University
New data, tools, and techniques are needed to evaluate the life cycle environmental and economic aspects
of nanomanufacturing to encourage sensible engineering decisions and policy. The objectives of this
research are to develop life cycle inventory data of nanomanufacturing, perform life-cycle analysis (LCA)
of nanotechnology and traditional processes and products, and then perform thermodynamic LCA and test
hypotheses for evaluating life cycle impact with limited information. This research will combine data
from the laboratory, LCA databases, and economic models through a multiscale LCA and test
thermodynamics-based hypotheses for evaluating life cycle impact of emerging technologies. This project
will develop techniques for gaining insight into the life cycle impact of emerging technologies and
provide a tool for LCA and economic analysis of polymer nanocomposites. The expected benefits of the
research include identifying and managing risk in research, development, and commercialization of
nanomanufacturing; minimizing irrational optimism or unfounded fear about nanotechnology; and
balancing harm to the environment and human health with economic feasibility.
GREEN MANUFACTURING
U.S. EPA STAR Grantees
Graft Polymerization as a Route To Control Nanofiltration Membrane Surface Properties
James Kilduff, Rensselaer Polytechnic Institute
This project will develop new nanofiltration membranes by modifying the surface structure of
commercial membranes at the molecular level via UV-assisted graft polymerization of hydrophilic
monomers using their patented method. The objective is to transfer major successful developments from
biotechnology applications to environmental protection. New materials will be developed that offer high
flux compared to commercial membranes (by improving membrane porosity), enhanced rejection of
inorganic anions and ionizable organic compounds (by controlling membrane pore size distribution and
surface charge), and enhanced ability to resist fouling by natural organic matter (NOM) by reducing
adhesion. Researchers seek to understand the characteristics of NOM accumulated on membrane surfaces
both in terms of resistance to flow (which can influence the cost of membrane processes) and its affects
on the transport and rejection of charged solutes. Results from this project will provide new approaches to
develop membrane materials that have superior performance characteristics in terms of both enhanced
rejection of charged contaminants and resistance to fouling by NOM. The research also will expand our
understanding of the role of membrane charge and NOM fouling layers on solute rejection by
nanofiltration processes. The proposed materials and processes will provide new options for controlling
risks from contaminants of water supplies to protect human health and improve the performance of
membrane treatment technologies, while reducing associated costs.
Development of Nanocrystalline Zeolite Materials as Environmental Catalysts
Sarah Larsen, University of Iowa
The objective of this research project is to develop nanometer-sized zeolites as environmental catalysts.
Nanocrystalline zeolites possess very large internal and external surface areas that can be exploited for
many different applications. This research project demonstrated that zeolite particle size can be system-
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atically tuned in the nanometer range by varying reaction conditions. The nanocrystalline zeolites can be
functionalized to control their properties and used as building blocks for hierarchical zeolite structures,
such as fibers, films, and hollow zeolites. The most recent work of the project has been to exploit these
materials for environmental applications. Environmental applications for nanocrytalline zeolites and
hierarchical structures include adsorption of volatile organic chemicals such as toluene from aqueous or
gaseous solutions and the potential for selective catalytic reduction of NOi with hydrocarbons on
nanocrystalline Y zeolites.
Sustainable Biodegradable Green Nanocomposites From Bacterial Bioplastic
for Automotive Applications
Manjusri Misra, Michigan State University (Lawrence Drzal, PI)
This research project seeks to replace existing petroleum-derived polypropylene (PP)/TPO (thermoplastic
olefin) based nanocomposites with environmentally friendly nanocomposites produced from bacterial-based
bioplastic (polyhydroxyalkanoate, PHA) reinforced with compatibilized nanoclay for automotive applications.
The goal of this research is to replace conventional petroleum-based clay-reinforced polymers with bio-
degradable plastics. The approach used was to toughen poly(hydroxybutyrate) (PHB) to improve impact
properties; however, the modulus and consequently the stiffness of the material was reduced. To
counteract this, nanoclay platelets were introduced to improve the stiffness to some extent. A new
research approach is being used to address the main drawbacks of PHB and explore the nucleating effect
of expanded graphite nanoplatelets on PHB. Expanded graphite nanoplatelets (xGnP) act as efficient
nucleating agents for PHB. PHB crystallizes faster in the presence of xGnP, a behavior desirable for
dynamic processing conditions. The effects of xGnP on the crystallization behavior and morphology of
PHB provide a foundation for further investigations of PHB/xGnP systems, with the objective of
obtaining advanced bionano-composites with controllable thermal and mechanical properties.
Ecocomposites Reinforced With Cellulose Nanoparticles: An Alternative
to Existing Petroleum-Based Polymer Composites
William Winter, Syracuse University
The objective of this project is to explore the preparation, characterization, and formulation of cellulose
nanoparticles into nanocomposites. The project also examined other substances, such as chitin nanocrystal
preparation and derivatives. Further work in characterizing the effects of cellulose-graft-PCL and PHA
composites is in progress. A challenge will be the scale up of the composite extrusion and compounding
processes. Scale-up batches as large as 400 grams have been prepared. Challenges include separation of
particles from acid, with experiments underway on acid recycling and minimization of reaggregation of
particles. Biodegradation studies are another component of the research. Biodegradable particulates to
replace glass fiber, and other nonbiodegradable inorganics in composites can provide environmental
benefits. Cellulose-based materials have the potential to be used to generate wholly biodegradable nano-
composites, and commercialization discussions are underway with several companies.
Nanostructured Microemulsions as Alternative Solvents to VOCs in Cleaning
Technologies and Vegetable Oil Extraction
Anuradee Witthayapanyanon and Linh Do, University of Oklahoma (David Sabatini, PI)
The objective of this project is to develop surfactant-based aqueous solvents to replace organic solvents in
cleaning processes and vegetable oil extraction. Linker-based formulation rivals the performance of
perchloroethylene, an organic solvent. For textile cleaning, linker-based and extended surfactant-based
micro-emulsion as a pretreatment system can remove at least 50 to 85 percent of hydrophobic stains from
fabric. In addition, the project has demonstrated low interfacial tension for vegetable oils with extended
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surfactants, and surfactant enhanced oil extraction achieves 86 to 92 percent recovery of peanut oil. The
results to date are encouraging for the possible use of surfactant-based microemulsions as organic solvent
replacements. Future work for the project includes studying the synergism of a combination of extended
surfactant and linkers and the detergency mechanisms. Extraction efficiency of olive oil and soybean oil
and the effect of pH on vegetable oils extraction also will be examined. Additional research is needed on
the quality of oil extracted by the surfactant-enhanced vegetable oi! extraction technique.
REMEDIATION
U.S. EPA STAR Grantees
Dendritic Nanoscale Chelating Agents: Synthesis, Characterization,
Modeling and Environmental Applications
Mamadou Diallo, California Institute of Technology
This project explores the fundamental science of metal ion uptake by poly(amidoamine) (PAMAM)
dendrimers in aqueous solutions and assesses the extent to which this fundamental knowledge can be used
to develop: (1) high capacity and reusable chelating agents for industrial and environmental separations;
and (2) FeS laden nanoparticles with enhanced reactivity, selectivity, and longevity for reductive
detoxification of tetrachloroethylene (PCE) in aqueous solutions and subsurface formations. The overall
results of this research suggest that dendritic nanoscale chelating agents provide unprecedented
opportunities for developing a new generation of efficient and cost-effective high capacity and recyclable
chelating agents and FeS dendrimer nanocomposites to treat water contaminated by toxic metal ions and
redox active solutes. The research has led to a patent for recovery of metal ions from aqueous solutions by
dendrimer-enhanced filtration. The system is modular, flexible, and scalable for nanofiltration, ultra-
filtration, and microfiltration. Comparatively lower operating pressure, energy consumption, and loss of
ligands can be achieved with dendrimer-enhanced ultrafiltration to recover metal ions from contaminated
water.
Developing Functional Fe(0)-Based Nanoparticles for In Situ Degradation
ofDNAPL Chlorinated Organic Solvents
Gregory Lowry, Carnegie Mellon University
The objective of this project is to develop and test reactive nanoscale particles for in situ delivery to, and
degradation of, chlorinated solvents that are present as DNAPLs in the subsurface. The hypothesis under
consideration is that the surfaces of reactive Fe°-based nanoparticles can be modified with amphiphilic
block copolymers to maintain a stable suspension of the particles in water for transport in a porous matrix,
as well as to create an affinity for the water-DNAPL interface. Delivering reactive particles directly to the
surface of the DNAPL-water interface will decompose the pollutant into benign materials, reduce the
migration of pollutant during treatment, and reduce the time needed to remove residual pollution by other
means, such as natural attenuation. Research in the first 2 years of the project has focused on: (1)
identifying suitable Fe° nanoparticles and understanding the properties that control their reactivity with
TCE; (2) synthesizing and characterizing amphiphilic block copolymer-modified nano-iron; and (3)
evaluating the DNAPL-targeting and transport properties of the resulting polymer-modified functional
nanoparticles.
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Nanostructured Catalytic Materials for NOX Reduction Using Combinatorial Methodologies
Selim Senkan, University of California, Los Angeles
The objective of this project is to integrate combinatorial catalysis methodologies with nanostructured
materials processing for the discovery, optimization, and better understanding of new, active, and stable
catalytic materials for the reduction of NOX under lean-burn conditions. These objectives will be accom-
plished by systematically exploring a large number of different combinations of metals and nano-
structured metal oxide supports. Libraries of catalytic materials were prepared by individually
impregnating five support materials of AI2O3, CeO2, SiO:, TiO2, and Y-ZrC>2 with salt solutions of 42
elements from the periodic table, resulting in five different metal loadings. These support materials were
chosen because of their durability in harsh engine exhaust conditions. Catalytic materials were then tested
for their NO reduction activities using array channel microreactors and mass spectrometry. The test
conditions realistically simulated the actual engine-out conditions, thereby rendering the findings
immediately relevant to automobile exhaust treatment catalysis. These systematic investigations led to the
discovery of Pt/TiO2 and Pt/SiO2 as the most significant materials, both of which exhibited superior
performances, reducing the levels of NO by 25 percent and 20 percent, respectively.
A Bioengineering Approach to Nanoparticle-Based Environmental Remediation
Daniel Strongin, Temple University
The objective of this project is to develop a bioengineering approach that can be used to create nano-size
catalytic materials as the basis for new remediation strategies. The project will assess the potential use of
ferritin, and ferritin-derived compounds, as catalysts in environmental degradation processes. The ferritin
system has the advantage of being environmentally benign and biodegradable. The research focuses on:
(1) the development of a bioengineered synthesis of a variety of homogeneous nano-sized metal and
metal oxide particles; (2) the determination of the electronic properties of the nanoparticles and their
reduced forms (i.e., the base metal) as a function of size; and (3) a determination of the reactivity of the
particles toward beneficial environmental chemistry, as a function of size and electronic structure. The
ultimate goal is to develop new nano-sized materials based on ferritin that may serve as catalysts in
(photo)chemical degradation processes of common contaminants. The research is expected to provide
significant insight into the dependence of electronic structure and reactivity on chemical composition of
nanoparticles.
Nanoscale Bimetallic Particle for In Situ Remediation
Wei-xian Zhang, Lehigh University
The primary goal of this research is to continue the research and development of the nanoscale bimetallic
particle technology for in situ remedial applications. The objectives of the project include: (1) optimiza-
tion and scale-up of the synthetic method(s) to facilitate the rapid and cost-effective production of
nanoparticles for large-scale field applications; (2) extension of the technology by expanding the scope of
amenable contaminants to include perchlorate and toxic metals (e.g., Cr(VI)); and (3) investigation of
transport, reactions, and long-term performance with various chlorinated organic compounds and heavy
metal ions.
Transformation of Halogenated PBTs With Nanoscale Bimetallic Particles
Wei-xian Zhang, Lehigh University
The objective of this research is to develop nanoscale bimetallic particles (e.g., Fe-Pd) with sizes in the
range of 1-100 nm for treatment of hydrophobic, persistent, bioaccumulative toxic compounds (PBTs).
Nanoparticles have higher contaminant availability and higher reactivity towards PBTs. State-of-the-art
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techniques of nanomaterial synthesis will be exploited to create novel materials for PBT treatment. The
synthesized nanoparticles will be systematically assessed for the rate and extent of PBT degradation. The
model compounds selected for this research include: polychlorinated biphenyls (PCBs), hexachlorocyclo-
hexanes (HCHs), chlorinated benzenes, and phenols. Transport and reactions of the iron nanoparticles 5n
porous media will be studied in laboratory soil columns. Fluorescent tagging methods will be used for
detailed microscopic analysis of particle transport and deposition in porous media.
Nanostructured Catalysts for Environmental Remediation of Chlorinated Compounds
Yunfeng Lu, Tulane University
The use of zero-valent iron for in situ remediation of chlorinated compounds may be used more
effectively by minimizing aggregation and improving mobility during in situ remediation. The objective
of this research project is to design mesoporous supports for nanoscale iron catalysts with controlled
functionalities to allow catalyst partitioning to the orgamc/aqueous/interfacial regions. The principles of
surfactant self-assembly can be used to create structured mesoporous supports. The goals for continuing
and future work include: (1) generating iron containing silica nanoparticles; (2) functionalizing silicas
with hydrophobic/hydrophilic ligands to control catalyst mobility and partitioning characteristics; (3)
evaluating catalytic activity towards TCE breakdown using static experiments; (4) developing a novel
microcapillary video-microscopy based technique to visualize contaminant droplet and catalyst particle
characteristics during in situ remediation; and (5) performing column experiments to measure the efficacy
of contaminant break-down during in situ remediation.
Synthesis and Application of a New Class of Stabilized Nanoscale Iron Particles
for Rapid Destruction of Chlorinated Hydrocarbons in Soil and Groundwater
Dongye Zhao, Auburn University
The goal of this research is to develop a cost-effective, in situ remediation technology that employs a new
class of dispersed iron-based nanoparticles for the rapid destruction of chlorinated hydrocarbons in soil
and groundwater. The specific objectives are to: (1) synthesize a new class of stabilized iron-based nano-
particles using low-cost and "green" stabilizers such as starches and celluloses; (2) test the effectiveness
of the stabilized nanoparticles for dechlorination of select contaminants (TCE and PCBs) in soil and
ground-water; and (3) test the feasibility of an in situ remediation process that is based on the
nanoparticles. The preliminary data showed that a water-soluble or sodium carboxymethyl cellulose
(CMC) can serve as the dispersant to stabilize palladized iron (Fe-Pd) nanoparticles. Compared to
nonstabilized Fe-Pd particles, the stabilized nanoparticles displayed markedly improved physical stability,
soil dispersibility, chemical reactivity, and reactive longevity. Column tests showed that the stabilized
nanoparticles can readily disperse in a loamy-sand soil and then be recovered completely. Batch
dechlorination tests demonstrated that the CMC-stabilized nanoparticles degraded TCE 29 times faster
than nonstabilized counterparts based on the pseudo first-order rate constant.
Nanostructured Membranes for Filtration, Disinfection, and Remediation
of Aqueous and Gaseous Systems ,
Svetlana Zivanoic, University of Tennessee (Kevin Kit, PI)
The objectives of this research project are to: (1) develop electrospun nanofiber chitosan membranes to
treat aqueous and gaseous solutions through filtration, disinfection, and metal binding; (2) understand the
electrospinning process for chitosan to control membrane structure; (3) investigate the effect of membrane
structure on filtration, disinfection, and metal binding; and (4) optimize performance/efficiency of
chitosan membranes. The central hypothesis for the research is that the degree to which these nanofiber
chitosan membranes effectively filter contaminants, kill microbes, and bind harmful metals will be
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optimized by minimizing the size of the electrospun fibers and maximizing the available chitosan surface
area. The results of this research could provide a new nanostructured system for the treatment and
remediation of aqueous and gaseous environments with improved efficiency over current filtration
technologies. The goal is that microorganisms are removed via filtration and killed on contact. The
multiple functions that these chitosan membranes will serve (removal, destruction, and immobilization of
toxic species) could make them cost-effective replacements for multiple treatment systems presently in
use. Environmental advantages include the fact that chitosan is biodegradable and no organic solvents are
required for processing.
SENSORS
U.S. EPA STAR Grantees
Metal Biosensors: Development and Environmental Testing
Anne Anderson, Utah State University
Cells of a soil-borne pseudomonad respond differentially to the toxic metals copper and cadmium. The
objective of this research project is to develop and test biosensors and DNA arrays that will detect copper
or cadmium and indicate the bioavailability of these metals to a bacterium. Constructs have been made
and responses are beginning to be determined; however, it will be important to identify specific metal
promoters. Bioinformatics and proteomics can be used to investigate genes as candidates for a biosensor
method. Project research has demonstrated that some metal complexes can be detected by pseudomonads.
Genomic studies demonstrated that a subset of the genome is sensitive to the presence of metals and that
some genes not predicted by bioinformatics show a change in gene expression as a result of the presence
of cadmium or copper. Future work will include testing new Lux fusions for specificity and sensitivity,
investigating the role of polyphosphate for understanding the phenomenon of stasis induced by cadmium
exposure, investigating the use of specific RNA/DNA hybridizations to determine altered gene
expression, and testing the effects of copper citrate, cadmium citrate, and other complexes with bioassays
and physical measurements.
Nanosensors for Detection of Aquatic Toxins J
Robert Gawley, University of Arkansas
This project involves the development of nanosensors for detection of saxitoxin, which causes paralytic
shellfish poisoning, and other marine toxins that are problematic to human health such as tetrodotoxin,
brevetoxin, ciguatoxin, and domoic acid. The objective of this project is to covalently attach fluorescent
dendrimers to a surface for sensing. Saxitoxin is a marine toxin that is difficult to detect. The standard
chemical assay method is a mouse bioassay with an analytical goal of 1 um This project's objective is to
utilize fluorescence sensing to detect saxitoxin and other marine toxins. Selecting the correct fluorophore
for use in detection is a challenge. The present work is focused on mimicking the natural action of
saxitoxin by placing a sensor inside a large dendrimer, allowing the saxitoxin to diffuse to the core, and
then measuring the fluorescence response. The first attempt was a coumarin sensor anchored in the den-
drimer nanoenvironment. Coumarin is not a good fluorophore in this case because the shellfish extract has
an absorbance at the same wavelength as the coumarin. A longer wavelength fluorophore is needed, and
research has begun on a visible chromophore, boron dipyrrin. Future work will examine incorporation of
a visible fluorophore into the dendrimer, testing of an improved peptide for binding, and evaluation of the
fluorescence response with shellfish extracts.
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Neuromorphic Approach to Molecular Sensing With Chemoreceptive
Neuron MOS (CoMOS) Transistors
Edwin Kan, Cornell University
An ideal microsensor for autonomously monitoring chemical and molecular environmental hazards in
both water and air should .simultaneously have high sensitivity, high selectivity, large dynamic range, low
manufacturing cost, simple .calibration/reset protocols, long lifetime, .field reconfigurability, and low
power consumption. The objective of this research project is to develop a silicon-based neuron MOS
transistor with a novel extended floating-gate structure that permits molecular and chemical sensing.
Project work has improved the fluidic integration for molecule-blocking pores to obtain more reliable
transient and small signal information and allow for better cleaning. Accomplishments include totally
CuMOS integrated FET devices with extended floating gates for chemical sensing. The floating-gate
structure for electron-tunneling operations provides more degrees of freedom for sensing, and CuMOS-
integration enables detailed control circuits. Project work has demonstrated that universal sensor arrays
can be constructed to have specificity that allows for pH sensing, pressure sensing, and photodetection
using different coatings on the sensor. Future work will focus on designing a nanoelectronic interface
using C60 or nanotubes as the floating gate.
Compound Specific Imprinted Nanospheres for Optical Sensing
Barry Lavine, Oklahoma State University
The objective of this research project is to investigate the use of molecularly imprinted polymer particles
as the basis of a sensitive and selective method for the detection of Pharmaceuticals and other emerging
organic contaminants. Such imprinted particles can be incorporated into hydrogel membranes. The project
presently is focusing on theophylline. Theophylline-imprinted particles are suspended in polyvinyl
alcohol hydrogel and exposed to varying concentrations of theophylline. In the absence of theophylline,
the hydrogel is turbid because the refractive index of the particles is greater than the refractive index of
the hydrogel. In the presence of aqueous theophylline, the polymer will swell. The increased water
content in the particles causes a decrease in particle refractive index, bringing them closer to the refractive
index of the hydrogel. This leads to a decrease in membrane turbidity, which is proportional to
theophylline concentration in the solution. Changes in the swelling of the theophylline-imprinted particles
are monitored using surface plasmon resonance spectroscopy.
Carbon Nanotube Self-Assembly in a VOCs Monitoring Platform
Somnath Mitra, New Jersey Institute of Technology
The objective of this project is to take different steps of a measurement process and integrate them onto
one platform. This integration is especially important for environmental monitoring, which involves com
plex metrics and low concentrations integrated into a single device. Specifically, a single device for
monitoring VOCs in air is being developed that exploits the self-assembly properties of carbon nanotubes
as they are grown on microstructures. Nanoparticles offer some distinct advantages, such as a very large
surface area and unique absorption characteristics. Fabrication requires self-assembly, and the process
needs to be fine tuned for each application. The project has used three different ways to make carbon
nanotubes, including catalytic arc, catalytic laser ablation, and catalytic chemical vapor deposition.
Catalysis for single-walled nanotubes is more difficult than for multi-walled nanotubes. GC columns
coated with carbon nanotubes are able to do the same type of separation as traditional GC columns, and
results exhibit classical chromatography features. Nanotube synthesis is a balancing act of catalyst,
residence time, and the precursor used. Thickness levels are not consistent along the length of the column,
and this phenomenon needs further investigation.
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Advanced Nanosensors for Continuous Monitoring of Heavy Metals
Omowunmi Sadik, State University of New York, Binghamton
The objective of this research project is to incorporate novel, colloidal-metal nanoparticles into a bed of
electrically conducting polymers, and then use these for the development of nanosensors. The highlight of
efforts during the second year of the project was the development of a Pd synthetic approach that was
tested as an environmental catalyst for the conversion of Cr(VI) to Cr(III). One of the synthetic nano-
structured materials developed under the project was tested as an environmental catalyst for the
conversion of higher valent to low valent Cr in soil and water samples. The real sample application of the
Pd nanoparticles-sulfur mixture tested using soil samples produced more than 92 percent conversion in
the presence of Pd-NPs/S within 1 hour. In contrast, only 33 percent of the same concentration was
converted to Cr{III) in the absence of Pd-NPs/S. This represents a greater than 500-fold improvement in
conversion rate compared to current microbial approaches. This work offers a new and safe application of
nanotechnology for the reduction of high oxidation state heavy metal pollutants.
Ultrasensitive Pathogen Quantification in Drinking Water Using High
Piezoelectric PMN-PT Microcantilevers
Wan Shih, Drexel University
The objective of this research project is to develop highly piezoelectric microcantilever arrays for in situ,
rapid, simultaneous multiple pathogen quantification in source water with the ability to detect pathogens
using electrical means with unprecedented sensitivity (10~15 g). The short-term goals for the second year
of the project were to: (1) examine in situ, direct detection of various waterborne pathogens, including
Escherichia coli 0157:H7 and Salmonella typhimurium using PZT cantilevers with antibodies
immobilized on various surfaces, such as gold and titanium; and (2) use the highly reactive PMN-PT
precursor powder developed by the researchers to fabricate PMN-PT freestanding films by tape casting
and use the freestanding PMN-PT films. Research results have shown sensitive Escherichia coli OJ57:H
and Salmonella detection. Smaller cantilevers lead to increased detection sensitivity. Another
advancement has been the development of a microcantilever array. Both the material and sensors are
patented. Real-time detection has been achieved through the use of the arrays with a flow cell. In this
system, no adjustment is needed because there are no background values to subtract. This method was
used for detection of Bacillus anthracis spores and proteins such as prostrate specific antigen. The
portable system includes an electrical unit, sensor, and flow cell. Future work involves development of
array piezoelectric microcantilever sensors to allow for protein detection at the unprecedented pg/mL
levels and single-cell bacteria detection.
Low-Cost Organic Gas Sensors on Plastic for Distributed Environmental Sensing
Vivek Subramanian, University of California, Berkeley
This project involves the development of arrayed organic field-effect transistors (FETs) that are easily
arrayed at low cost via printing, flexible for easy dispersal, and trainable via electronic nose architecture.
To ensure accuracy, measurements are performed with a calibrated precision semiconductor parameter
analyzer. The arrays are built from the bottom up with the channel material exposed. Because of the
ability to use ink jet printing, .the cost is relatively low. Sensitivity of the arrays is a challenge. Often a
tradeoff occurs between sensitivity and stability. Using functional groups to make parts of an array
specific can enhance sensitivity without the need for larger arrays. Nonlinearity as a result of sample drift
over time is a challenge. Progress has been made on sensor integration, including developing methods for
dealing with drift. The challenge continues to be the optimization of structure and process flow,
particularly in terms of stability, reliability, and fluid compatibility. Future project work will focus on the
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development of fluid-compatible derivatives and deployment for testing of environmentally relevant
analytes.
A Nanocontact Sensor for Heavy Metal Ion Detection
Nongjian Tao, Arizona State University
The objective of this research project is to develop a high-performance and low-cost sensor for the initial
onsite screening of surface and groundwater that w5H provide early warning and prevention of heavy
metal ion pollution. The highly integrated sensor will consist of arrays of different nanojunctions,
including nanocontacts, molecular junctions, and polymer nanojunctions, for simultaneous detection of a
range of different chemical species. Recent project work has focused on the use of peptides as molecular
probes. Protein molecules are good at recognizing other molecules, and combinatorial chemistry can
provide tools for construction of molecular probes. Results of aniline functionalized with peptides showed
that the peptides chosen had high affinity for the metal ion and provided sensor specificity.
Characterization by Fourier Transform Infrared Spectroscopy (FTIR) revealed that the peptide structure is
in polymer film. Results from tests of the nanojunction metal ion sensors found the ability to detect
copper as low as 4 ppt and nickel as low as 22.5 ppt. The sensors are reusable approximately nine times
for metal ion detection. Using the nanojunction sensors to analyze drinking water from Tempe, Arizona,
showed agreement with analysis by atomic absorption spectroscopy.
Nanomaterial-Based Microchip Assays for Continuous Environmental Monitoring
Joseph Wang, Arizona State University
The project goal is to create a novel microfluidic device for rapidly, continuously, and economically
monitoring different classes of priority pollutants. The laboratory-on-a-chip concept provides
opportunities to meet this goal, but integration of functional elements is required. A protocol for rapid
screening and fingerprint identification of phenols was developed that uses microchip flow-injection
analysis for fast screening and early detection of total phenolic compounds and then allows for switching
to the fingerprint mode. Screening is rapid, 5 to 10 seconds, and individual fingerprinting occurs within 2
to 3 minutes, with the ability to switch between total and individual protocols quickly. Progress was made
on the macro-to-micro interface through incorporation of a Sharp microchip inlet to facilitate
electrokinetic loading of samples directly into the separation microchannel. Integrating additional sample-
handling capabilities and incorporating various nanomaterials can further enhance such microsystems.
The electrocatalytic activity and resistance to surface fouling of carbon nanotube materials provides
improved sensitivity, stability, and resolution compared to common carbon-electrode detectors.
Conducting-Polymer Nanowire Immunosensors Array for Microbial Pathogens
Ashok Mulchandani, University of California, Riverside
Waterborne pathogens are responsible for 90 percent of waterborne disease outbreaks in the United
States, but 50 percent of outbreaks have no causative agents identified because of inadequacy of detection
methods. The objective of this project is to develop a novel technique for the fabrication of antibody-
functionalized nanowires that are individually addressable and scalable to high-density immunosensor
arrays for label-free, real-time, rapid, sensitive and cost-effective detection. Silicon nanowire and carbon
nanotube FETs have challenges, and conducting polymers may be useful to meet these challenges.
Aspects of conducting polymers that are favorable include conductivity that can be reversibly modulated
more than 15 orders of magnitude and the ability for electrochemical synthesis. Benign conditions enable
the direct deposition of conducting-polymer materials with embedded bioreceptors in one step. This
project's future work includes demonstrating the ability to grow biologically functionalized nanowires of
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controlled dimension and obtaining an understanding of sensor sensitivity and selectivity, with the goal of
fabricating and evaluating a nanowire immunosensor array for multiple viruses.
Canadian Grantees
Exploring the Impact of a Nanostructure's Size and Shape on Cellular
Uptake, Clearance, and Metabolism
Warren Chan, University of Toronto
Novel discoveries on molecular differences between diseased and healthy cells and tissues and
developments of nanotechnology probes and tools are transforming the way we treat and diagnose
disease. Biological molecules provide a means to direct nanostructures to a diseased site where the
nanostructure can be optically, electrically, or magnetically lit up or treat the diseased site. A key to this
hybrid research field is the ability to engineer nanostructures with defined properties. Essentially, a
nanostructure provides a system that has custom-tunable function based on its size and shape. Recently,
the use of such nanostructures for cell, tissue, and animal imaging and therapeutic applications for the
early detection and treatment of cancer has been demonstrated. The interface of these two fields has
prompted several important questions, such as: Are the nanostructure's toxic? How does a cell process
these nanostructures? What is the fate and clearance of these nanostructures? Are these processes related
to the dimensional or surface chemical characteristics of the nanostructures? These fundamental questions
must be answered before nanostructures become useful for clinical applications. Dr. Chan's presentation
included a discussion on the techniques and research results in elucidating these fundamental questions.
The size and shape-dependent uptake of the nanostructures in cell cultures and in animals using model
nanostructures also was discussed. The results from these studies provide guidance for the design of
nanostructures for biomedical applications.
TREATMENT
U,S. EPA STAR Grantees
Applications ofNanoscale Tunable Biopotymersfor Heavy Metal Remediation
Ashok Mulchandani, University of California, Riverside
Heavy metal accumulation in soil leads to water contamination and biomagnification. Conventional
approaches are often inadequate in reducing the concentrations to satisfy sub-ppb regulatory limits. The
advantages of nanoscale biopolymers derived from biological building blocks include: easy production by
engineered bacteria; they are environmentally friendly (i.e., they are biodegradable and contain no
hazardous compounds); they can be engineered for specific metal recognition and binding; and they can
be reversibly precipitated by change in temperature. The objective of this research was to design a new
generation of elastin-like protein (ELP) biopolymers with enhanced metal binding affinity and selectivity
for water and soil remediation. ELP biopolymer with enhanced metal binding affinity and selectivity was
designed successfully. The work of the project provided a novel, environmentally friendly, and green en-
gineering method for removal of heavy metal from water and soil.
Synthesis, Characterization, and Catalytic Studies of Transition Metal Carbide
Nanoparticles as Environmental Nanocatalysts
Ismat Shah, University of Delaware
Current regulations based on the 1990 Clean Air Act Amendments (CAAA) require vehicle NOX
emissions to be less than 0.6 g/mile with 100,000 hours duration. In 2007, further reduction in NO*
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emissions, below 0.2 g/mile, is mandated. Because of the limited availability of the platinum (Pt)-group
metals, an alternative catalyst is required. The objective of this research project is to explore the
possibility of using alternative catalytic materials, transition metal carbides, and oxycarbides (defined as
oxygen-modified carbides) to replace Pt-group metals for the reduction of NOX. Transition metal carbides
are known to have catalytic properties similar to Pt-group metals, and WC (Tungsten Carbide), in
particular, has been used in isomerization reactions as a replacement for Pt. The research project
demonstrated that WC nanoparticles effectively reduce NOX, and WC composition and structure
determine the conversion efficiency. In pure NOX, catalyst oxidation occurs at temperatures of 500 °C and
beyond. CO addition can add to the conversion efficiency and stability of the catalyst. Further
stabilization is needed through the addition of O or N.
A Novel Approach To Prevent Bioclde Leaching
Patricia Heiden, Michigan Technological University
Newer wood preservative formulations are formulated without chromium and arsenic to reduce negative
environmental impact; however, because of this, the preservatives are more likely to leach to the
environment. This research project is based on a hypothesis that increased biocide loss leads to decreased
longevity of wood products, leading to increased biocide use, which increases stress on sensitive
environments. The objectives of this research project are to "fix" biocides into nanoparticles to provide a
stable, controlled situation that could reduce or prevent leaching. The biocide release is controlled
through the nanoparticles' matrix hydrophobicity. The expected result of the research is to increase wood
product lifetime using less biocide. Wood treatment systems using nanoparticles and conventional
preservatives will be compared. The key tasks will be to: (1) verify equivalent loading in wood; (2)
perform leaching studies; and (3) examine the biological efficacy of the different treatments compared to
untreated wood.
FATE/TRANSPORT
U.S. EPA STAR Grantees
Chemical and Biological Behavior of Carbon Nanotubes in Estuarine Sedimentary Systems
P. Lee Ferguson, University of South Carolina
The objectives of this project are to: (1) determine factors controlling the fate of single-wall nanotubes
(SWNTs) in estuarine seawater, sediment, and sediment-ingesting organisms; (2) examine the impact of
SWNTs on the disposition of model organic contaminants in estuarine sediments; (3) determine whether
the presence of SWNTs in estuarine sediments affects the bioavailability of model organic contaminants
to suspension- and deposit-feeding estuarine invertebrates; and (4) assess the toxicity of SWNTs to a
model deposit-feeding estuarine invertebrate in seawater and/or in combination with estuarine sediments.
Fate tracking in estuarine sediments is expected to provide information about potential disposition of
SWNTs discharged to the aquatic environment. Sorption and bioavailability studies will reveal the
possible impact of SWNTs on the fate and effect of hydrophobic organic contaminants in estuarine
sediments. In addition, toxicity studies are expected to lead to an increased understanding of the potential
effects of SWNTs on trophically important estuarine invertebrates in sediments.
A Focus on Nanopartkulate Aerosol and Atmospherically Processed Nanoparticulate Aerosol
Vicki Grassian, University of Iowa
Manufactured nanoparticles may become suspended in air during production, distribution, use and
disposal, and become a component of the tropospheric aerosol and thus the air we breathe. The objectives
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of this research are to: (1) characterize a variety of manufactured nanomaterials in terms of their size,
shape, bulk and surface properties (metal, oxide and semiconductor nanoparticles); (2) determine if
engineered nanomaterials are particularly deleterious to health compared to particles from combustion
processes that have been more extensively studied; and (3) evaluate the relative health effects caused by
different surface coatings on the nanoparticle. This research focused on one of the smallest commercially
available nanoparticles, 5 nm TiO2. These particles are pure anatase, and their surfaces are truncated by
surface hydroxyl groups and adsorbed water under ambient conditions (i.e., there are no surface coatings
present from manufacturing). The particle surfaces can be modified by adsorption, and thus the impact of
coatings can be studied in future experiments. The particles form an aerosol using a nebulizer. The
particles aggregate and form an aggregate size of approximately 100 nm as determined from TEM and
SMPS. Sub-chronic inhalation exposure to TiC>2 nanoparticles caused an increase in the number of
activated macrophages; however, mice recovered after 3 weeks post exposure. No signs of pathological
changes in BAL fluid or in lung tissue were found in this study. /
Transformations of Biologically Conjugated CdSe Quantum Dot; Released Into Water and Biofilms
Patricia Holden, University of California, Santa Barbara
Regarding cadmium selenide (CdSe) quantum dots in soil and
occur, this project is addressing the following questions: (1) Wha
What are the effects of QDs on bacteria? (3) How do fates and
size, environmental factors (light, pH, reduction potential, oxygen^t
(biofilm or planktonic)? Thus far, the results have facilitated s
dependent quantum dot interactions with bacteria: external nons]
QDs cannot passively diffuse into cells; specific binding and non p,
recognized by receptors on the cell envelope and light-mediatec
radicals facilitates transmembrane transport, allowing conjugated
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Nanotechnology and the Environment: Applications and Implications Progress 'Review Workshop HI
both organic and inorganic contaminants to nanomaterials and the fate and transport of naphthalene (an
organic contaminant) and colloidal C«0 particles in soil column.
The Bioavailability, Toxicity, and Trophic Transfer of Manufactured
ZnO Nanoparticles: A View From the Bottom
Paul Bertsch, University of Georgia
The objectives of this project are to evaluate the bioavailability and toxicity of manufactured zinc oxide
nanoparticles to the model soil bacteria Burkholderia cepacia and the model detritivore Caenorhabditis
elegans, as well as the ability of nanoparticles to be transferred from one trophic level to the next in a
simple food chain consisting of pre-exposed B. cepacia and C. elegans. In addition, the project will
evaluate the synergistic or antagonistic effects of zinc oxide nanoparticles on the toxicity of copper to B.
cepacia and C. elegans. The project is based on the hypotheses that: (1) the bioavailability and toxicity of
manufactured zinc oxide nanoparticles increase with decreasing particle size; (2) the toxicity of such
nanoparticles is lower than an equivalent concentration of dissolved zinc ions; (3) the bioavailability and
toxicity of zinc oxide nanoparticles introduced via trophic transfer differs from the bioavailability and
toxicity of direct exposure; and (4) the nanoparticles alter the bioavailability and toxicity of dissolved
metals.
Hysteretic Accumulation and Release of Nanomaterials in the Vadose Zone
Tohren Kibbey, University of Oklahoma
Any nanomaterial that is widely used will ultimately enter the environment. The vadose zone may
provide either a sink for nanomaterials and prevent their spread throughout the environment, or it may act
as a long-term contaminant source. The project objectives are to: (1) study the vadose zone accumulation
and release of a wide range of manufactured nanomaterials, and (2) examine hysteretic interactions at air
and water interfaces and specific mineral surfaces. The expected outcomes from this research include: (1)
improved a priori assessment of manufactured nanomaterial mobility in the environment and associated
risk; (2) indications about nanomaterial classes likely to accumulate in the vadose zone and roles of
mineral surfaces, air/water interfacial areas, and wetting/drying history on accumulation; and (3) new
information necessary to assess the role of vadose zone interactions in decreasing or increasing ultimate
risk to human or environmental health.
Fate and Transformation of 'Cf0 Nanoparticles in Water Treatment Processes
Jaehong Kim, Georgia Institute of Technology
Carbon nanomaterials are hydrophobic and form water stable aggregates. Such aggregates impact nano-
materials entering water treatment processes. Treatment processes can include both oxidation and filtra-
tion. This research project will test three hypotheses. Hypothesis 1: When subjected to oxidation by com-
monly used oxidants and disinfectants such as ozone, ultraviolet (UV) light, free chlorine, and
monochtoramine, the unique electron-rich surface chemistry of nano-C60 will lead to various chemical
transformations. Hypothesis 2: A unique, weakly negatively charged surface of nano-C60 will lead to
unique electrostatic and hydrophobic interactions with metal hydroxide soluble complexes and
precipitates in coagulation processes employing divalent metals, with polymeric membrane surfaces in
membrane filtration processes, and with hydrophobic surfaces of activated carbon in adsorption
processes. Hypothesis 3: A unique size characteristic of nano-C60 will lead to unique filtration
characteristics when filtered through nanoporous membranes, and unique mass transfer and adsorption
kinetics/equilibrium characteristics when adsorbed by activated carbon with varying pore size
distributions.
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Fate and Transport of C60 Nanoparticles in Unsaturated and Saturated Soils
Kurt Pennell, Georgia Institute of Technology
The objectives of this research project are to: (1) investigate the fate and transport of C,;o nanomaterials in
water-saturated soils as a function of soil properties and systems parameters; (2) assess the effects of Ceo
nanomaterials on soil water retention, water flow, and transport in unsaturated soils; and (3) develop and
evaluate a numerical simulator to describe C60 nanomaterial transport, retention, and release in subsurface
systems. To understand the fate and transport of nanomaterials in water-saturated soils, experiments will
be conducted in water-saturated clean porous media, natural soils, and in heterogeneous aquifer cells. To
understand the fate and transport of nanomaterials in unsaturated soils requires investigation of solution
and interfacial properties as well as pressure-saturation relationships and unsaturated hydraulic con-
ductivity. A mathematical model of nanomaterial fate and transport in porous media will be developed. It
is hypothesized that classical particle filtration theory will not be sufficient to accurately describe C60
nanoparticle retention and release. The goal will be to incorporate short-range hydrophobic and hydrate
forces equations to improve the predictions of particle retention and release.
NSF Grantees
Cross-Media Transport, Transformation, and Fate of Carbonaceous Nanomaterials
Linsey Marr, Virginia Polytechnic Institute and State University
Nanoparticles released into the atmosphere undergo transformations that change the particles' size,
chemical composition, and surface properties. When these "aged" particles later deposit onto the earth's
surface, they may have very different fates in the aquatic and terrestrial environments compared to the
"fresh" compounds. The objective of this research is to characterize the behavior of "fresh-unaltered"
versus atmospherically "aged" nanomaterials in aquatic and terrestrial systems. The research approach is
to quantify the rate of reaction of airborne carbonaceous nanomaterials (CNMs) with ozone, evaluate
transport of "fresh" and atmospherically "aged" CNMs in porous media, and quantify adhesive and
repulsive forces between CNMs and environmental surfaces. The expected benefits include prediction of
the fate of CNMs in the environment and assessment of the potential for human exposure. Such
knowledge could assist in overcoming barriers to the use of nanomaterials for environmental applications.
TOXICITY
U.S. EPA STAR Grantees
Short-Term Chronic Toxicity of Photocatalytic Nanoparticles to Bacteria, Algae, andZooplankton
Chin-Pao Huang, University of Delaware
The objectives of this research project are to: (1) determine the short-term chronic toxicity of photo-
catalytic nanoparticles to aquatic organisms, including bacteria, algae, and daphniad; and (2) assess major
factors affecting the ecotoxicity of photocatalytic nanoparticles. Among the target organisms studied
were: bacteria (Escherichia coll), algae (Selenastrum capricornutum), and daphniad (Ceriodaphnia
dubia). The small size, surface charge, photocatalysis properties, and chemical composition of
nanoparticles are all factors that could lead to their toxicity. Results show that in the size range of 5 to 30
nm, there appeared to be no significant difference in toxic response to the photocataiytic nanoparticles,
but more data are needed. Cell damage was observed in terms of lipid oxidation and cellular respiration.
The dose-response information, exposure experiments, and toxicity studies of this research will provide
information on the evaluation of ecological risk associated with nanoparticles, including mechanistic
information on the effects of nanoparticles on trophically important aquatic organisms.
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Physical and Chemical Determinants of Nanofiber/Nanotube Toxicity
Robert Hurt and Agnes Kane, Brown University
The project approach is to develop and test a model nanomaterial system with well-characterized, acces-
sible, nanophase iron and to characterize and test complex, commercial multi-walled nanotubes in four
forms—as produced, vendor purified, vendor purified and mechanically damaged, and vendor purified
and oxidatively damaged. Toxicity assays include iron mobilization experiments, assessment of plasmid
DNA single strand breaks, and macrophage viability and morphology. Results of the research show that
carbon nanofibers containing surface nanophase iron exhibit key indicators of potential toxicity and that
unpurified multi-walled nanotubes contain mobilizable, redox-active iron. Purification greatly reduces
iron mobilization and DNA breaks, whereas mechanical grinding has no measurable effect though
oxidation may re-expose some encapsulated iron. Future work will include investigation of cellular
mechanisms of nanomaterial uptake, characterization of iron mobilization from a broad range of
nanomaterials (additional multi-walled nanotubes, single-walled nanotubes, magnetic nanoparticles, and
reference materials), assessment of Fe mobilization, and initiating work on nickel- and cobalt-containing
carbon nanotubes and nanofibers.
The Fate, Transport, Transformation, and Toxicity of Manufactured
Responses of Lung Cells to Metals in Manufactured Nanoparticles
John Veranth, University of Utah
It is assumed that because of their high surface area, nanoparticles are likely to induce larger responses in
cells than their micron-sized counterparts. In addition, it is hypothesized that the transition metals in
nanoparticles induce pro-inflammatory cytokine production via reactive oxygen species production. The
approach used in this research includes the physical characterization of commercially available metal
oxide nanoparticles, in vitro cell culture screening assays, and in vivo studies to establish health relevance.
Preliminary results of the in vitro assays used to date show that the metal oxide nanoparticles are not
highly potent compared to micron-sized particles of the same compound or compared to positive controls
that are representative of environmental particulate matter. More work is needed. Future work will
involve quantitative real-time polymerase chain reaction to measure many gene messages simultaneously.
Preliminary gene array studies can provide candidate genes to match to cell culture results.
Nanomaterials in Drinking Water
Paul Westerhoff, Arizona State University
The objectives of this project are to: (1) characterize the fundamental properties of nanomaterials in
aquatic environments; (2) examine the interactions between nanomaterials and toxic organic pollutants
and pathogens (viruses); (3) evaluate the removal efficiency of nanomaterials by drinking water unit
processes; and (4) test the toxicity of nanomaterials in drinking water using a cell culture model system of
the epithelium. This study considers the physical, chemical, and biological implications of nanomaterial
fate and toxicity in systems that will provide insight into the potential for nanomaterials to be present and
of health concern in finished drinking water. The first year of the project focused in part on
methodological advances. This included demonstrating that commercial nanoparticles do not behave as
discrete nanoparticles in aqueous systems, and aggregation of these materials results in particles less than
1 um. This research has focused on metal oxide nanoparticles, and understanding how surface change
(zeta potential) affects the removal of nanoparticles during simulated drinking water treatment.
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Microbial Impacts of Engineered Nanoparticles
Pedro Alvarez, William Marsh Rice University
Responsible usage of nanomaterials .in commercial products and environmental applications and prudent
management of the associated risks require an understanding of nanoparticle mobility, bioavailability, and
ecotoxicology. This project will elucidate processes governing the transport and microbial impacts of two
classes of catalytic nanomaterials in soil-water systems: fullerenes and metallic nanoparticles (e.g., TiO2,
ZnO, and Fe(0)). The specific tasks will be to: (1) characterize nanomaterials size, shape, functionality,
reactivity, aggregation, deposition potential, and bioavailability; (2) screen nanomaterials of varying sizes
and properties for bacterial activity; (3) discern bacterial physiologic characteristics that confer resistance
(or susceptibility) to catalytic nanomaterials; (4) evaluate the potential for fullerene biotransformation by
reference bacteria and fungi; and (5) assess the impact of simulated nanomaterial releases on microbial
diversity and community structure. At the conclusion of this project, there will be an improved under-
standing of the chemical and physical factors that control nanoparticle mobility and bioavailability, and
their impacts on microbial activities, diversity, and community structure. This will benefit risk assessment
and management efforts, and may contribute indirectly to the development of nanotechnology-based
disinfection and biofouling control strategies.
Role of Particle Agglomeration in Nanoparticle Toxicity
Lung-Chi Chen, New York University (Terry Gordon, PI)
This research project focuses on the hypothesized difference in the toxicity of fresh (predominantly
singlet) versus aged (predominantly agglomerated) carbon nanoparticles. The objectives are to: (1)
measure the agglomeration rate of several types of carbon nanoparticles; (2) identify whether
agglomeration is affected by differing exposure conditions, including humidity and particle charge; and
(3) compare the toxicity of singlet versus agglomerated particles in mice exposed via the inhalation route.
The research will establish the agglomeration of freshly generated carbon nanoparticles at various
distances (i.e., aging times) downstream from particle generation in a dynamic exposure system. In
addition, mice will be exposed to nanoparticles at various stages of particle agglomeration and the lungs
will be examined for injury and inflammation. Previous toxicological studies of nanoparticles will
provide the basis for the research. These studies demonstrated that freshly formed nanoparticles produce
lung injury and inflammation in mice, and the gene expression patterns were dramatically different than
those produced by endotoxin and ozone.
Structure-Function Relationships in Engineered Nanomaterial Toxicity
Vicki Colvin, William Marsh Rice University
The overarching objective of this project is to provide the first structure-function relationships for nano-
particle toxicology. The specific objectives of the research are to: (1) expand the characterization of nano-
particle structure in biological media; and (2) characterize the effects of nanoparticles on cell function.
This data will be used to test the hypothesis that nanoparticle structure (e.g., size and shape) controls
cytotoxicity directly. A secondary hypothesis is that of the four major materials parameters in engineered
nanoparticles (size, shape, composition, and surface), surface will be the most important in governing
cellular effects. These hypotheses will be tested in several major classes of nanoparticles. The
introduction of a new class of materials into consumer products will require information about the
potential behavior and risks that these systems pose to the environment and people. Risk management will
be improved with the information provided in this research, particularly in that structure-function
relationships for several major classes of nanomaterials will be established.
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Uptake and Toxicity of Metallic Nanoparticles in Freshwater Fish
Nancy Denslow, University of Florida (David Barber, PI)
The objectives of this project are to: (1) determine if fish exposed to metallic nanoparticles exhibit dif-
ferent responses than those exposed to dissolved metals; (2) determine if changing particle properties alter
biological responses to a given metal; and (3) evaluate an in vitro model of nanoparticle-induced gill
toxicity for its ability to predict in vivo responses. This project will characterize nanoparticles (Al, Ag, Ni,
and Ti) in terms of size distribution, surface area, agglomeration, and particle number. Zebrafish will be
exposed to metallic nanoparticles and dissolved metals for 96 hours. The general toxicity, tissue
histology, ATPase activity in gill, GSH, TBARS, and tissue metal count will be determined. Microarray
experiments will be performed to determine pathways that are affected by exposures. Finally, an in vitro
gill cell line will be developed to identify mechanisms of toxicity.
Cellular Uptake and Toxicity of Dendritic Nanomaterials: An Integrated
Physicochemical and Toxicogenomics Study
Mamadou Diallo, California Institute of Technology
This project seeks to advance the fundamental understanding of the relationships between the interactions
of ethylene diamine core poly(amidoamine) dendrimers with cell membranes and their vascular and
ingestion toxicity. Physical-chemical surrogates and atomic force microscopy will be used to characterize
the interactions of dendrimers with cell membranes. Molecular dynamics simulations will be used to
determine the three-dimensional structures and physical-chemical properties of the dendrimers in aqueous
solutions and to characterize their mechanisms of interactions with cell membrane bilayers. The research
also will characterize the vascular and ingestion toxicity of dendrimers through in vitro measurements of
cell viability and toxicogenomics studies of human endothelial and kidney cells.
Acute and Developmental Toxicity of Metal Oxide Nanoparticles in Fish and Frogs
Chris Theodorakis, Southern Illinois University
>
Nanoparticle exposure may be an ecological hazard that affects the survival, growth, development, egg
hatchability, and metamorphosis of larger aquatic organisms such as fish and frogs. The objective of this
project will be to determine the acute and chronic toxicity metal oxide nanoparticles (Fe2O3, ZnO, CuO,
and TiO2) in fathead minnows (Pimephase promelas) and African clawed frog (Xenopus laevis). The
approach will be flow-through exposure, with nanoparticle suspension in water. The expected benefits are
hazard identification of nanoparticles, which is necessary for ecological risk assessment of these particles
at an early stage in the development of this technology.
NanoIP-Canada Grantees
Interactions Between Semiconductor Nanoparticles and Biomembranes and DNA
Jay Nadeau, McGill University
This project will quantify the interactions of QDs with cell membranes, cellular proteins, DNA, and
whole cells with the goal of identifying the exact conditions under which the particles can damage cells.
This will result in the design of simple tests for researchers to use that will predict the cellular toxicity of
nano-sized materials based on physical properties such as size and fluorescence. Researchers also will
determine whether specific classes of molecules, including DNA molecules, make QDs more reactive and
hence more toxic, which will allow for recommendations for handling and disposing of these particles in
biological experiments. The photophysics of QDs, particularly their size, redox potential (which depends
not only on band gap, but on the presence of surface states) have a great influence on the interactions of
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these particles with biological cells and structures. Electron transfer processes should be sought as causes
of selective uptake of specific sizes of QDs. Common biomolecules also can sensitize QDs, making them
more photoreactive and able to damage cell membranes with or without Cd release. DMA damage,
however, has so far only been seen when Cd is released in significant quantities.
Understanding the Light-Induced Cytotoxicity of Quantum Dots: A Cellular,
Photophysical, and Mechanistic Approach
Francoise Winnik, University de Montreal
QDs, nanometer-sized light emitting semiconductors, are emerging as a new class of fluorescent probes
for in vivo and cellular imaging. Factors contributing to the safe use of QDs need to be established, as the
large-scale manufacture and handling of QD and the number of patients and attending staff that could be
exposed is considerable. The objectives of this research are to develop a methodology to monitor QD
cytotoxicity via chemical and photochemical studies coupled with in vitro assessment of key cellular
pathways, and confirm the relative importance of hypothesized mechanisms of QD cytotoxicity. Methods
such as solution photophysics, cell imaging, and quantitative analysis of released toxic ions will be used
to assess the effects of irradiation and QD composition on ions released and on cell death and to probe
how bioconjugation and surface modification affect ion release, QD photophysics, and cellular pathways
implicated in QD cytotoxicity. The overall goal is to explore if common properties of QD-cell interactions
can.be identified as useful predictors of QD-induced cytotoxicity.
Other Grantees
Assessment of the Environmental Impacts of Nanotechnology on Organisms and Ecosystems
Jean-Claude Bonzongo, University of Florida
The goal of this project is to develop an understanding of the potentially complex interplay between
manufactured nanomaterials (MM) and the health of organisms and ecosystems. The research hypothesis
is that chemical elements used in the production of MN could lead to environmental dysfunctions due to:
(1) the potential toxicity of these elements and their derivatives; (2) the nanometer-sizes that make MN
prone to biouptake/bioaccumulation; and (3) the large surface area that might lead MN to act as carriers/
deliverers of pollutants adsorbed onto them. To address this broad hypothesis, toxicological approaches at
the organism level in combination with experimental investigations at the system level will be used. In
addition, the bioaccumulation tendency of MN with contrasting chemical and physical properties will be
theoretically assessed by molecular modeling, which will assess possible damage to the cell membranes
caused by MN and test the ability of MN to cross cell membranes. The proposed combination of toxico-
logical, biogeochemical, and modeling expertise in the assessment of the potential impacts of MN on
biota and the environment is anticipated to advance discovery, as well as our understanding of the
behavior, fate, and impact of MN in the environment. At the very least, the anticipated findings could
provide arguments that would help avoid the dispersal of MN until more is known about their
environmental implications.
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Nanotechnology (aid the Environment: Applications and Implications Progress Review Workshop HI
EXPOSURE
U.S. EPA STAR Grantees
Health Effects of Inhaled Nanomaterials
Ting Guo, University of California, Davis (Kent Pinkerton, PI)
Epidemiological and lexicological studies on the effects of participate air pollution support the premise
that ultrafine or nanosize particles cause pulmonary inflammation as well as systemic effects. This project
will test the hypothesis that inhaled nanomaterials cause respiratory effects in the form of oxidative stress
and inflammation. Such events will lead to release of pro-inflammatory cytokines as well as other
mediators to induce cell proliferation and alterations in the normal cellular milieu of the airways and
alveoli of the lungs. Researchers will test whether these health impacts of nanomaterials on the respiratory
system are driven in large measure by: (1) particle size, (2) particle composition, and/or (3) trace con-
taminants associated with the manufacturing process of nanomaterials. The expected results from this
research include: (1) characterization of aerosolized nanotubes, ultrafine TiO2, and carbon black (CB)
under environmentally relevant conditions found in the workplace; (2) the influence of uniquely distinct
forms of nanotubes to produce health effects in the respiratory system; and (3) the impact of trace metals
associated with nanotubes to enhance/cause health effects due to inhalation.
Nanomaterial Interactions With Skin
Nancy Monteiro-Riviere, North Carolina State University
The objective of this research is to assess the nature of interactions between manufactured nanoparticles
and skin, focusing on dermal absorption and cutaneous toxicity issues. Multi-walled carbon nanotubes
without chemical modification or adjuvant treatments are capable of entering the cells and eliciting a
biological response. Project work demonstrated that FITC labeling allows for imaging of fullerene
penetration through the epidermal layer and the dermis. Surfactants play a major role in penetration of
fullerenes into the skin. Studies performed with quantum dots of two different sizes/shapes and with three
different types of coatings showed that these nanoparticles can penetrate through the epidermal and
dermal layers of the skin. Ongoing and future studies will assist in defining the structure-activity
relationships of various nanomaterials. The results of this research provide insight into the nature of the
potential hazard to nanomaterials and an initial estimate of dermal exposure parameters that can be used
to design more definitive studies.
Repercussion of Carbon-Based Manufactured Nanoparticles
on Microbial Processes in Environmental Systems
Ronald Turco, Purdue University
This project aims to answer the following questions: (1) How are environmental microorganisms
impacted by manufactured nanomaterials? and (2) What is the ultimate fate of manufactured nanomaterial
in the environment? Investigators will examine how aerobic microorganisms in soil react to and alter
themselves (or not) in the presence of carbon-based manufactured nanoparticles. Investigators also will
examine how aerobic microorganisms in soil react to and alter carbon-based manufactured nanoparticles
and how the change in their chemical structure during this process affects toxicity and impacts soil
processes. In addition, baseline information on the toxic effects of carbon-based manufactured
nanoparticles on aquatic bacteria will be determined.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Iron Oxide Nanoparticle-Induced Oxidative Stress and Inflammation
Hong Yang, University of Rochester (Alison Elder, PI)
Nanoparticles can evade normal clearance mechanisms in the lung, thus increasing the likelihood that
they will come into contact with several cell types where they will cause oxidative stress and
inflammation. The clearance evasion and, possibly, the interactions with cells can lead to translocation to
extrapulmonary tissues. The objectives of this project are to: (1) compare oxidative stress and toxicity of
nanoparticles; (2) measure pulmonary and cardiovascular effects following inhalation and intravenous
exposures in rats; and (3) measure translocation to extrapulmonary sites. This project will provide dose-,
size-, and composition-related toxicological information about nanoparticles and will explore their
translocation to extra-pulmonary tissues. The insight gained regarding mechanisms of response to
nanoparticles and their dis-position after exposure can be used to predict outcomes of human exposures in
environmental, occupational, and therapeutic settings.
Mechanistic Dosimetry Models of Nanomaterial Deposition in the Respiratory Tract
Bahman Asgharian, CUT Centers for Health Research
The goals of this project are to: (1) develop dosimetry models capable of calculating the retained dose in
the lungs of humans and animals; and (2) assess risk to people from exposure to nanoparticles by
interspecies data extrapolation. The objectives of this research are to: (1) study diffusive and convective
mixing of nanoparticles; (2) extend existing models of particle deposition in the lungs of rats and humans
to the size range of nanomaterial; and (3) validate the model by comparison with measurements. This
research effort will result in: (1) deposition measurements of nanosized particles in casts of human and rat
nasal upper respiratory tract (URT) airways; (2) semi-empirical relationships to predict nanomaterial
deposition in the URT airways; (3) respiratory tract deposition models of nanoparticles and nanotubes in
humans and rats; (4) measurements of regional and lobar deposition of nanomaterial in the heads and
lungs of rats; and (5) a user-friendly software package to implement models and provide rapid simulation
capability.
Chemical Fate, Biopersistence, and Toxicology of Inhaled Metal Oxide Nanoscale Materials
Jacob McDonald, Lovelace Respiratory Research Institute
This project will test the hypothesis that the biological disposition, persistence, and toxicity of metal
oxides change with size (comparisons between nanoscale and micron size) and composition (comparison
between SiC>2 and A12O3) of metal oxide powders. Researchers will test the hypothesis that metal oxide
particles that are manufactured in the nanoscale have: (1) longer biological persistence; and (2) increased
pul-monary and systemic toxicity relative to the same metal oxides of larger sizes. The two primary
research objectives are to: (1) determine biological disposition (translocation/elimination/persistence) by
measure-ment of residual metal oxide in plasma and six target organs (lung, brain, liver, kidney, spleen,
intestine); and (2) determine local (lung/respiratory tract) and systemic toxicity by measurements of
sensitive biochemical markers of inflammation and oxidative stress in addition to histopathological
analysis.
NIOSH Grantees
Assessment Methods for Nanoparticles in the Workplace
Patrick O'Shaughnessy, The University of Iowa
The primary objectives of this project are to: (1) provide the scientific community and practicing in-
dustrial hygienists with verified instruments and methods for accurately accessing airborne levels of
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
nanoparticles; and (2) assess the efficacy of respirator use for controlling nanoparticle exposures.
Researchers plan to satisfy these objectives through a combination of laboratory and field-based studies
centered on the following specific aims: (1) identify and evaluate methods to measure airborne nano-
particle concentrations; (2) characterize nanoparticles using a complementary suite of techniques to assess
their surface and bulk physical and chemical properties; and (3) determine the collection efficiency of
commonly used respirator filters when challenged with nanoparticles.
Monitoring and Characterizing Airborne Carbon Nanotube Particles
Judy Xiong, New York University School of Medicine
The objective of this project is to develop a comprehensive, yet practical, method for sampling,
quantifying, and characterizing carbon nanotubes (CNT) particles in air, which will be capable of: (1)
classifying sampled particles into three categories (tubes, ropes, and non-tubular particles); (2) measuring
the number concentrations and size distributions for each type; and (3) measuring the shape characters of
CNTs (diameter, length, aspect ratio, and curvatures). Successful completion of this project will produce a
validated method for sampling airborne CNTs in workplaces and a practical method using Atomic Force
Microscopy (AFM) image analysis to classify sampled CNT particles by type, and to separately quantify
and characterize each type. The expected benefits from this research are: (1) methods for determination of
potential health risks caused by worker exposure to the various types of nanoparticles; (2) a foundation
for development of field and personal sampling devices for CNTs; and (3) information that is essential for
studies on potential toxicity, source attribution, and control efficacy of this new type of material.
NSF Grantees
Gene Egression Profiling of Single-Walled Carbon Nanotubes: A Unique
Safety Assessment Approach
Mary Jane Cunningham, Houston Advanced Research Center.
There is increasing concern about potential adverse effects of engineered nanoparticles on the
environment and on human health. Engineered nanomaterials will be exposed to human cells in vitro, and
their toxicity will be assessed using the innovative technology of high throughput gene expression
microarrays. The four main objectives of this research project are to: (1) compile reproducible gene
expression profiles of primary human lung cells exposed to SWNTs; (2) apply different tiers of
computational analysis to determine if toxicity is present; (3) compare across biological tissues with
previous data from human skin cells; and (4) lay the foundation for a "systems biology" approach for
predictive toxicity by merging traditional risk assessment methods with new toxicogenomics
computational methods.
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Section 1. Aerosols
EPA is interested in furthering the scientific understanding of the microphysical phenomena of aerosol par-
ticles. Aerosols can be nanoscale, in the size range of 1-100 nm. Aerosol research will provide better data for
models used in atmospheric and stratospheric particle concentration predictions. Such understanding will lead
to protection of human health in terms of providing mechanisms for minimizing respiratory health effects, as
well as providing protection from stratospheric ozone depletion that results from particle deposition on cloud
condensation nuclei.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Elemental Composition of Freshly Nucleated Particles
Murray V. Johnston
University of Delaware, Newark, DE
Abstract
The main objective of this research project is to develop a method for real-time sampling and analysis of indi-
vidual airborne nanoparticles in the 5-20 nm diameter range. The size range covered by this method is much
smaller than existing single particle methods for chemical analysis. Because particles in this size range are
close to their origin, chemical composition measurements should provide greater insight into particle formation
mechanisms.
Nanoparticles will be classified by elemental composition using aerosol mass spectrometry. The aerosol will
be drawn directly into a mass spectrometer where individual particles are analyzed in real time by laser abla-
tion. To increase the sampling efficiency for particles in the 5-20 nm diameter range, a quadrupole ion guide
will be used to focus particles into the ablation laser beam path. Quantitative measurements of elemental com-
position will be achieved by complete atomization and ionization of individual particles using a high energy
laser pulse to create a nano-plasma. This method will be used to study a variety of particle formation proc-
esses. Although laboratory investigations are emphasized in this work, the instrumentation will be suitable for
field experiments.
Nanometer diameter aerosol particles are important precursors of larger particles in the accumulation mode.
There is growing evidence that ultrafine particles are toxic and that particle number can be an important indica-
tor of human health. Controlling ultrafine particle concentrations requires an understanding of the gas phase
condensation processes that lead to new particle formation. Measuring the elemental composition of individ-
ual, nanoparticles will help quantify the relative contributions of the various sources.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Ion-Induced Nucleation of Atmospheric Aerosols
Peter H. McMurry and FredEisele
University of Minnesota, Minneapolis, MN
Abstract
The objective of this research project is to study the role of ion-induced nucleation as a mechanism for produc-
ing new nano-sized particles in the atmosphere. The researchers hypothesize that: (1) nucleation processes in
different locations are driven by different gas phase species and can be homogeneous and/or ion-induced de-
pending on time and locale; and (2) ion-induced nucleation events can be due to the growth of either positive
or negative ions, and different gas phase species are responsible for bursts of intermediate and large positive
and negative ions. The ultimate goal of this project is to develop experimentally verified models for the forma-
tion of ultrafine atmospheric particles by nucleation.
This study will include both laboratory and field research and will involve the measurement of ion mobility
spectra (nominal ion sizes 0.4 to 15 nm) and ion composition. Ion composition will be measured by tandem
mass spectrometry and will include measurements of both positive and negative ion composition during nu-
cleation events, which has not been done before. A microphysical model will be developed to interpret the
data. This model will attempt to reconcile observed time-dependent trends in ion mobility distributions and
aerosol charge distributions.
Recent epidemiological research has suggested that, on a mass basis, ultrafine particles can be more harmful to
human health than larger particles. Furthermore, ultrafine particles formed by nucJeation can grow into cloud
condensation nuclei that can impact on the earth's radiation balance. This project complements other ongoing
research in the laboratories in which the homogeneous nucleation is being studied through reactions of neutral
molecules in the atmosphere. The results of this study will be useful to modelers, who require experimentally
verified models of microphysical processes to evaluate aerosol climatic effects, human exposure, and so on.
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Section 2. Life-Cycle Analysis
Life-cycle analysis (LCA) is an approach to evaluating the environmental consequences of a product from
"cradle to grave." The assessment considers all stages along the life cycle of a compound, including pro-
duction, use, recycling, and disposal. As new nanomaterials are discovered and commercial and environmental
opportunities and risks are observed, there is an important need for EPA to improve its ability to respond to
these emerging opportunities and risks as early as possible.
Information is needed to engage in efforts to encourage the early redesign of products and services and
effectively prevent the adverse impacts of these materials on human health and the environment. A multi-
disciplinary and coordinated policy approach, including an analysis of product life-cycle impacts, along with a
materials flow analysis, starting with the conversion of raw materials, manufacture, use, and disposal, is
necessary to encourage a culture of stewardship in relationship to the development and application of emerging
nanotechnologies and materials.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Evaluating the Impacts of Nanotechnology via
Therm odynamic and Life-Cycle Analysis
BhavikR. Bakshl
Ohio State University, Columbus, OH
Abstract
The proposed research will develop original life cycle inventory data for the manufacture of polymer nano-
composites, test two new hypotheses for thermodynamics-based Life Cycle Assessment (LCA) and impact
assessment with limited information, and develop a tool for exploring economic and environmental aspects of
alternate manufacturing combinations for selected nanoproducts and conventional processes. The following
hypotheses will be tested: (1) Among alternatives for making similar products, the one with a higher life cycle
thermodynamic efficiency has a smaller life cycle impact; and (2) Emissions with a smaller life cycle thermo-
dynamic efficiency have a larger ecotoxicological impact. The second law of thermodynamics and hierarchical
systems theory support these hypotheses. Validating them, however, has been challenging.
Through collaboration with leading academic groups, industry, and a national laboratory, life cycle inventory
data and modules will be developed for the synthesis and use of nanoclays and carbon nanofibers. These mod-
ules will be combined with life cycle information at different spatial scales, ranging from equipment to ecosys-
tems, and used to perform multiscale or hybrid LCA of several potential products. Different scenarios for the
manufacture, use, end of life, emissions and exposure of typical, consumable and durable products, such as
automotive body panels and food wrapping film, will be analyzed, along with estimates of uncertainty. Ther-
modynamic LCA will treat industrial and ecological systems as networks of energy flow and combine the fea-
tures of systems ecology, LCA, and systems engineering. The proposed hypotheses will be tested in a statisti-
cal sound manner via several case studies.
LCA of nanotechnology is essential for guiding and managing risk in research, development, and commer-
cialization, while preventing irrational optimism or unfounded fear of this emerging field. However, it presents
formidable obstacles because data and knowledge about resource consumption, and emissions and their impact
are either unknown or not readily available. This work will lay the foundation for LCA of polymer nanocom-
posites and other emerging technologies. Validation of the first hypothesis will provide useful insight about
nano versus traditional technologies, while the second hypothesis will provide a proxy for the ecotoxicological
impact of the emissions. These hypotheses will be useful for nano and other emerging technologies before de-
tailed emissions data and ecotoxicological studies are available. As more information about manufacturing,
emissions and their impact becomes available, it will be incorporated in the proposed studies and tool.
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Section 3. Green Manufacturing
Nanotechnology offers the possibility of changing the manufacturing process in two ways: (1) incorporating
nanotechnology for efficient, controlled manufacturing wouid drastically reduce waste products; and (2) the
use of nanomaterials as catalysts for greater efficiency in current manufacturing processes would minimize or
eliminate the use of toxic materials and the generation of undesirable by-products and effluents. Research may
involve nanotechnology related to improved industrial processes and starting material requirements, develop-
ment of new chemical and industrial procedures, and materials to replace current hazardous constituents and
processes, resulting in reductions in energy, materials, and waste. Potential examples of types of nano-
technology research that may lead to reduction or elimination of pollutants of concern include: atomic-level
synthesis of new and improved catalysts for industrial processes; adding information into molecules (analo-
gous to DNA) that build new molecules; self-assembling molecules as the foundation for new chemicals and
materials; and building molecules "just in time" in microscale reactors.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Development of Nanocrystalline Zeolite
Materials as Environmental Catalysts
Sarah Larsen
University of Iowa, Iowa City, IA
Abstract
This project involves the development of nanometer-sized zeolites and zeolite nanostructures as environmental
catalysts. Zeolites, which are widely used in applications in separations and catalysis, are aluminosilicate mo-
lecular sieves with pores of molecular dimensions. Recently, there has been a great deal of interest in the syn-
thesis of nanocrystalline zeolites (zeolites with crystal sizes of 100 nm or less) and their unique properties rela-
tive to conventional micron-sized zeolite crystals. Nanocrystalline zeolites possess very large internal and ex-
ternal surface areas that can be exploited for many different applications. For example, nanocrystalline sili-
calite with a crystal size of 20 nm has an external surface area of approximately 175 m2/g (approximately 30
percent of the total surface area on the external surface). For comparison, the external surface area of a 1 mi-
cron silicalite crystal is approximately 2 m2/g, which accounts for less than 1 percent of the total surface area.
A key feature of nanocrystalline zeolites is that the external surface can be utilized as a reactive or sorbtive
surface resulting in materials with a wide variety of physical and chemical characteristics. In principal, bifunc-
tional zeolite materials can be designed in which the external and internal surfaces have different functions.
Nanocrystalline ZSM-5, silicalite (purely siliceous form of ZSM-5), and Y zeolites have been synthesized in
the researcher's laboratory with discrete crystal sizes as small as 15 nm. Hollow zeolite structures also have
been prepared using zeolite nanocrystals as seeds and mesoporous silica as a template and silica source for
zeolite growth. First, mesoporous silica is coated with nanocrystalline zeolite seeds. Then, the coated meso-
porous silica is subjected to a hydrothermal treatment in an autoclave. During the hydrothermal treatment, the
zeolite crystals grow larger using the mesoporous silica as the silicon source for crystal growth. Hollow zeolite
structures with controlled porosity have many potential applications in diverse areas, including drug delivery,
chemical storage, chemical sensors, and catalysis.
Applications of nanocrystalline zeolites in environmental protection will be discussed. In particular, the in-
creased adsorption capacity of nanocrystalline zeolites for volatile organic compounds such as toluene has
been demonstrated. In addition, unique reactivity of nanocrystalline NaY for the selective catalytic reduction
of NO2 with reductants such as propylene or urea has been investigated with Fourier Transform Infrared
(FTIR) spectroscopy. In the absence of oxygen and water, selective catalytic reduction of NOz with propylene
at low temperatures (473 K) resulted in the complete reduction of NO2 to N2 and O2. Nanocrystalline NaY zeo-
lite exhibits enhanced deNOx at low temperature (T = 473 K) compared to commercial NaY zeolite, as shown
by an FTIR study on the selective catalytic reduction of NO2 with urea. Silanol groups and extraframework
aluminum species on the external surface of nanocrystalline NaY were found to be responsible for the higher
selective catalytic reduction (SCR) reaction rate and decreased formation of undesired products relative to
commercial NaY zeolite. Isotopic labeling coupled with infrared analysis indicates that N-N bond formation
involves both a N-atom originating from NO2 and a N-atom originating from urea. Nanocrystalline alkali zeo-
lites can be visualized as new catalytic materials that have NO, storage capacity in the internal pores and high
reactivity on the external surface. This is the first clear example in the literature demonstrating that the in-
creased external surface area (up to ~40 percent of the total surface area) of nanocrystalline zeolites can be
utilized as a reactive surface with unique active sites for catalysis.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Development of Nanocrystalline Zeolite
Materials as Environmental Catalysts
Sarah Larsen
University of Iowa, Iowa City, IA
Environmental Implication/Application
Environmental catalysis involves the use of catalysts to solve environmental problems in areas such as emis-
sion abatement and environmentally benign synthesis. Many new catalysts and catalytic processes have been
developed to meet the challenges posed by environmental concerns. Recently, zeolites have emerged as impor-
tant materials for applications in environmental catalysis. Zeolites are aluminosilicate molecular sieves with
pores of molecular dimensions. Zeolites can be synthesized with a wide range of pore sizes and topologies and
are used in applications such as catalysis and chemical separations. The crystal size of zeolites formed during
conventional synthesis range in size from 1,000 to 10,000 nm. However, for some applications it would be
advantageous to employ much smaller nanometer-sized zeolite crystals in the range of 10-100 nm. Specific
advantages to be gained by using zeolite nanostructures include facile adsorption and desorption, the ability to
form dense films to facilitate separations applications, and optical transparency. Several applications of nano-
meter-sized zeolites to environmental catalysis are described below.
Environmental Remediation: NO, Emissions Abatement
The emission of NOX and NjO from stationary and automotive sources, such as power plants and lean-burn
engines, is a major environmental pollution issue. NOX leads to the production of ground-level ozone and acid
rain, and N2O is a greenhouse gas. The catalytic reduction of nitrogen oxides to N2 is an important environ-
mental challenge for scientists and engineers. Recently, the selective catalytic reduction of NO* and N2O by
hydrocarbons (SCR-HC) over transition-metal exchanged zeolites, particularly in the presence of oxygen, has
attracted much interest for emission abatement applications in stationary sources, such as natural gas fueled
power plants. SCR-HC of NO* and N20 shows promise for applications to lean-burn gasoline and diesel en-
gines where noble-metal three-way catalysts are not effective at reducing NOX in the presence of excess oxy-
gen. The SCR activity of nanocrystalline zeolites, such as NaY, has been investigated.
Adsorption of Volatile Organic Compounds (VOCs)
Zeolites are extremely good adsorbents for many applications involving the adsorption of VOCs from polluted
water or air. In this last application, the advantages of nanocrystalline zeolites for the adsorption of VOCs from
water and air will be exploited. The nanocrystalline zeolites synthesized in the researcher's laboratory will be
evaluated for the adsorption of a representative VOC, such as toluene. The adsorption properties of commer-
cial and synthesized zeolites for toluene will be compared. In addition, the nanocrystalline zeolites will be
chemically modified to tailor the hydrophobic/hydrophilic properties for applications in particular chemical
environments. For example, nanocrystalline ZSM-5 has been fimctionalized with octamethylsilane such that
the hydrophobicity was dramatically increased. The functionalized zeolites wiH then be evaluated for the ad-
sorption of toluene in aqueous solution.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Ecocomposites Reinforced With Cellulose Nanoparticles: An
Alternative to Existing Petroleum-Based
Polymer Composites
William T. Winter
State University of New York, Syracuse, NY
Abstract
The broad objective of this research project is to produce wholly biobased and biodegradable nanocomposites
using cellulose nanocrystals and nanofibers dispersed in biodegradable matrices. These nanocomposites will be
compared in terms of thermal, mechanical, and biodegradation properties with existing glass-filled composites
made from petrochemicals. During the past 4 months, a 22 L reactor has been acquired, and the problems of
scaleup in nanocrystal batch size are being explored. In addition, our own composite objects will be extruded
for testing, and biodegradation tests will be developed that are based on ASTM and ISO protocols.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Nanostructured Microemulsions as Alternative Solvents to VOCs in
Cleaning Technologies and Vegetable Oil Extraction
David Sabatini, Anuradee Witthayapanyanon, and Unh Do
University of Oklahoma, Norman, OK
Abstract
Introduction
Volatile organic compounds (VOCs), such as percholoroethylene (perc), hexane, and chloroform, have been
widely used as conventional solvents in cleaning technologies and vegetable oil extraction. These organic sol-
vents are classified as hazardous and probable carcinogenic substances. Although environmental contamina-
tion and health risks occur when using organic solvents in numerous operations, these organic solvents are still
used due to their ready availability and a high cleaning efficiency. Therefore, the goal of this research is to find
aqueous-based surfactant microemulsions that can replace VOC solvents with environmentally friendly sys-
tems.
Microemulsions contain nano-sized aggregates that can be used as extracting entities at the nanoscale level.
This project uses nanoscale microemulsion environments as receptors for oily soils. Microemutsions play a
key role in solvent replacement because of the ultralow interfacial tension (IFT) and ultrahigh so I utilization
properties of these systems. This project is focused on textile cleaning process and vegetable oil extraction ap-
plications.
Aqueous-Based Microemulsion for Textile Cleaning Process
In the textile cleaning process, long chain alkanes and highly hydrophobic oils (e.g., hexadecane and motor oil)
were studied. Based on the hydrophobic nature of these oils, a special cleaning process, such as dry cleaning, is
required to remove hydrophobic oily soils from stained fabrics. However, the solvent emission and energy
consumption during dry cleaning operation create environmental concerns. An alternative to dry cleaning is
wet cleaning. Wet cleaning uses water and nonpolluting detergents instead of hazardous solvents that can be
used with computer-controlled washing and drying machines. Wet cleaning is more environmentally friendly
than dry cleaning while still maintaining the same cleaning efficiency. Therefore, in this project, the research-
ers have developed aqueous-based microemulsions for cleaning oily soils with more environmentally friendly
systems that can be applied to wet cleaning technology, thereby, replacing volatile organic solvents for textile
cleaning application.
First of all, microemulsion with target oils (hexadecane and motor oil) were forumlated. The researchers hy-
pothesized that the ultralow IFT and ultrahigh solubilization properties of middle phase microemulsion will
provide the best solvency for textile cleaning. In addition, the use of hydrophilic/lipophilic linkers improved
the formulations. The newly produced alkyl propoxylated sulfate surfactants, known as extended surfactants
(surfactants with "internal" linkers), have desirable properties for this application. The detergency of an or-
ganic solvent system (perc), conventional surfactant (sodium dioctyl sulfosuccinate, Aerosol-OT) with and
without linkers, extended surfactant, and commercial detergent were compared as shown in Figure 1.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
&$• '«
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
10.000
~ 1.000 -
1 0.100
t 0.010 -I
0.001
— *— AOT w/ Canola
-•— C12-14PO2EOSO4te w/ Canola
-*— C12-14PO-2BOSO4Na w/ Corn Oil
-e- C12-14PO-2EOSO4Na w/ Fteanut Oil
-*— C12-14PO-2BOSO4Na w/ Triotein
10
time (min)
15
20
Figure 2. IFT Measurement of conventional surfactant and extended-surfactant with vegetable oils.
Figure 3 shows the results of oil extracted by using the aqueous extended-surfactant-based formulation versus
aqueous enzymatic (1) and hexane methods. At low concentrations, ambient temperature and no additives, ex-
tended-surfactant systems show 90 percent of oil yield, which is very competitive with hexane-based and
aqueous enzymatic methods. In addition, extended-surfactants are able to produce ultralow IFT with a wide
range of edible oils; therefore, it is expected these techniques can be used as a universal method such like hex-
ane.
0.30wt%^ "0.35wt% " 2.5wt% ** Hexane.
# %• /•• ^tty"10-?? ^ -T tK v
^CI^IfiN^EQCCMla^ „ ^
Figure 3. Percentage of peanut oil extracted.
Reference:
i?
1. Sharma Khare SK, Gupta MN. Enzyme-assisted aqueous extraction of peanut oil. Journal of the Amercan
Oil Chemists'Society 2002;79(3):215-218.
Success Stories
Nanostructured microemulsions as alternative solvents to VOCs in cleaning technologies and vegetable oil
extraction. Recipient of JSD's Outstanding Paper Award for 2003.
Acosta EJ, Mai PD, Harwell JH, Sabatini, DA. Linker-modified microemulsions for a variety of oils and sur-
factants. Journal of Surfactants and Detergents 2003;6(4):353-363.
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Nanotecknology and the Environment: Applications and Implications Progress Review Workshop HI
Acosta EJ, Nguyen T, Witthayapanyanon A, Harwell JH, Sabatini DA. Linker-based bio-compatible micro-
emulsions. Environmental Science and Technology 2005;39(5):1275-1282.
Recipient of the Manuchehr (Manny) Eijadi Award and Honored Student Award, American Oil Chemist Soci-
ety Meeting, Salt Lake City, Utah, 2005.
Witthyapanyanon A, Do L, Acosta E, Harwell JH, Sabatini DA. Surfactant-based microemulsions for solvent
replacement. Presented at the 95th AOCS Annual Meeting and Expo, Cincinnati, OH, May 9-12, 2004 (oral
presentation).
Miscellaneous:
1. "Engineering student awarded for research." The Oklahoma Daily, February 12,2002;85(97).
2. "OU cleans up in cleaning up." Tulsa World, May 27, 2004.
3. "OU team finds solution to clean oil from water." The Oklahoman, May 25, 2004.
4. "Cleaning up with super soap." Sooner magazine, summer 2004.
5. "Collaborative clusters flourish: The Institute for Applied Surfactant Research." Evolve (the magazine of
the University of Oklahoma's College of Engineering), tall 2004;4(1).
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Section 4. Remediation
Cost-effective remediation techniques pose a major challenge for EPA in the development of adequate hazard
removal techniques that protect the public and safeguard the environment. EPA supports research that ad-
dresses new remediation approaches that are more effective in removing contamination in a more cost-
effective manner than currently available techniques. Substances of significant concern in remediation of soils,
sediment, and groundwater include heavy metals (e.g., mercury, lead, cadmium) and organic compounds (e.g.,
benzene, chlorinated solvents, creosote, toluene). Nanotechnology offers the possibility of more effective
remediation due to the higher surface to volume ratios of nanomaterials, and it offers the possibility of novel
collection and separation protocols due to the unique physical properties of nanomaterials. Specific control and
design of materials at the molecular level may impart increased affinity, capacity, and selectivity for pollutants.
Reducing releases of such hazardous materials to the air and water, providing safe drinking water, and mini-
mizing quantities and exposure to hazardous wastes are among EPA's goals.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Dendritic Nanoscale Chelating Agents: Synthesis, Characterization,
Modeling and Environmental Applications
Mamadou S. Diatto1'2, Lajos Balogh3, William A, Goddard HI1, and James H. Johnson, Jr.2
'California Institute of Technology, Pasadena, CA; 2Howard University, Washington, DC;
3 University of Michigan, Ann Arbor, MI
Abstract
Dendrimers are highly branched nanostructures with controlled composition and architecture. Poly(amido-
amine) (PAMAM) dendrimers that possess functional nitrogen and amide groups are arranged in regular
"branched upon branched" patterns. Their high density of nitrogen ligands, along with the possibility of attach-
ing functional groups such as primary amine, carboxylate, hydroxyl, etc., to PAMAM dendrimers, can result in
a substantial increase in binding capacity for transition metal ions [e.g., Cu(II), Ag(I), Fe(III), etc.]. The well-
defined molecular compositions, sizes, and shapes of PAMAM dendrimers have also made them particularly
attractive as: (1) scaffolds for paramagnetic metal ions in magnetic resonance imaging; and (2) templates for
the synthesis of metal-bearing nanoparticles with tunable electronic, optical, catalytic, and biologic activity.
This project explores the fundamental science of metal ion uptake by PAMAM dendrimers in aqueous solu-
tions and assesses the extent to which this fundamental knowledge can be used to develop: (1) high capacity
and reusable chelating agents for industrial and environmental separations; and (2) FeS laden nanoparticles
with enhanced reactivity, selectivity, and longevity for reductive detoxification of tetrachtoroethylene (PCE) in
aqueous solutions and subsurface formations.
The overall results of this research suggest that dendritic nanoscale chelating agents provide unprecedented
opportunities for developing a new generation of efficient and cost-effective high capacity/recyclable chelating
agents and FeS dendrimer nanocomposites for treatment of water contaminated by toxic metal ions and redox
active solutes.
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Developing Functional Fe (O)-Based Nanoparticles for In Situ
Degradation of DNAPL Chlorinated Organic Solvents
Gregory V. Lowry, Bruno Dufour, Yueqiang Liu, Sara A, Majetich, Kris Matyjaszewski,
Tanapon Phenrat, Navid Saleh, Kevin Sirk, and Robert D. Tilton
Carnegie Mellon University, Pittsburgh, PA
Abstract
Introduction
Dense non-aqueous phase liquids (DNAPLs) in the subsurface remain an important and costly environmental
liability. DNAPL serves as a continuous long-term source of groundwater contamination. This project inte-
grates several basic science fields to advance a particle-based strategy for in situ DNAPL degradation by pro-
viding targeted delivery of reactive particles directly to subsurface DNAPL.
Over the past decade, laboratory and field studies have demonstrated that zerovalent iron and bimetallic col-
loids (Fe/Pd) can rapidly transform dissolved chlorinated organic solvents into nontoxic compounds.1"3 This
emerging technology also has the potential to address DNAPL contamination. The objective of this research is
to develop and test reactive nanoscale particles for in situ delivery to, and degradation of, chlorinated solvents
that are present as DNAPLs in the subsurface. The hypothesis under consideration is that the surfaces of reac-
tive Fe°-based nanoparticies can be modified with amphiphilic block copolymers to maintain a stable suspen-
sion of the particles in water for transport in a porous matrix, as well as create an affinity for the water-DNAPL
interface. Delivering reactive particles directly to the surface of the DNAPL-water interface will decompose
the pollutant into benign materials, reduce the migration of pollutant during treatment, and reduce the time
needed to remove residual pollution by other means, such as natural attenuation.
Research in the first 2 years of the project has focused on: (1) identifying suitable Fe° nanoparticies and un-
derstanding the properties that control their reactivity with trichloroethylene (TCE); (2) synthesizing and char-
acterizing amphiphilic block copolymer-modified nanoiron; and (3) evaluating the DNAPL-targeting and
transport properties of the resulting polymer-modified functional nanoparticies.
Results and Discussion
Identifying suitable Fe9 nanoparticies and understanding the properties that control their reactivity with
TCE. The TCE reaction rates, pathways, and efficiency of two types of nanoscale Fe° particles were measured
in batch reactors. The two types of nanoscale Fe° particles were synthesized from sodium borohydride reduc-
tion of ferrous iron Fe(B) and commercially available particles (RNIP) synthesized from the gas phase reduc-
tion of Fe-oxides in H2. Particle characterization indicated many similarities between the particles, but several
distinct differences between the particle types were found. TEM micrographs of the particles evaluated are
provided in Figure l(a,b). Both particle types showed a core-shell morphology. RNIP particles were crystalline
and had an Fe core and a magnetite (FesO^ shell. No other Fe-oxides were detected. Fe(B) (borohydride re-
duced particles) were amorphous ct-Fe°, and contained 4-5 wt percent boron (18 mol percent). Boron precipi-
tated on the outer shell of the particles (as borate) accounts for approximately 0.2-1 wt percent, so the remain-
ing boron is most likely present as a FeBx alloy.2'
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
b)
Figure 1. (a) Fe(B); (b) RNIP.
Reactivity was determined under iron limited (high [TCE]) and excess iron (low [TCE]) conditions, and with
and without added H2. The reactivity and efficiency of the two particle types were very different and strongly
influenced by the oxide shell properties and the presence of boron. For example, the main reaction products
using Fe(B) were primarily saturated (e.g., ethane, butane), while the reaction products using RNIP were pri-
marily unsaturated (e.g., acetylene, ethane).2 A concentration dependence on the TCE reaction rate and product
distribution was observed. Few chlorinated intermediated products were observed for either particle. The addi-
tion of H2 to the reactor headspace increased the reactivity of Fe(B), and these particles were able to use exter-
nally supplied H2 to reduce TCE, indicating that these particles are catalytic. RNIP particles did not display
this behavior. The ability of Fe(B) to catalyze the hydrodehalogenation of TCE is attributed to their amorphous
structure rather than the presence of boron in the structure.3 All of the boron in Fe(B) is released during reac-
tion with water and TCE, which may be problematic if boron degrades water quality or has human or ecotoxic-
ity.
Synthesis and TCE/tvater partitioning of amphiphilic block copolymer-modified nanoiron. Atom Transfer
Radical Polymerization (ATRP) was used to synthesize tailored block copolymers for hybrid nanoparticles.
Concerning the synthesis of Fe° nanomaterials, a technique was developed for building hydrophobic-
hydrophilic hybrids that consist of a short anchoring poly(methacrylic acid) block, a hydrophobic poly(methyl-
methacrylate) protective shell, and a hydrophilic poly(styrene sulfonate) outer block (Figure 2). This PMAAX-
b-PMMAy-b-PSSz architecture provides the desired characteristics (i.e., water solubility, strong electrosteric
repulsions, and an affinity for DNAPL). Using an emulsion procedure developed in the researcher's labora-
tory7, TCE-water emulsions were formed using nanoiron modified with these triblock copolymers (Figure 3).
Figure 3 shows that a distinct shell of aggregated iron nanoparticles surrounds the TCE droplets. The floccu-
lated particles surrounding the emulsion droplets appear to form dendritic structures, and the emulsion droplets
are held apart by these aggregates of particles. The width of the aggregated nanoiron shells around the droplets
is approximately 1 urn, indicating that they are approximately 5-10 particles thick. Nanoiron was not found
inside the emulsion droplets, which is consistent with the facts that the emulsion was of the oil-in-water type
and that the polymer-coated nanoparticles are not dispersible in pure TCE. The ability of these particles to
form a highly stable emulsion phase demonstrates the ability of amphiphilic triblock copolymer modified iron
nanoparticles to preferentially localize at the TCE/water interface.6
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
HO
S03H
Figure 2. Hydrophobic-hydrophilic triblock copolymer containing a short anchoring group (PMAA),
short hydrophobic section (PMMA), and an extended hydrophilic block (PSS).
Figure 3. Micrograph of emulsified TCE droplets in water stabilized by "raw" PMAA42-PMMA26-
triblock copolymer-modified iron nanoparticles (Saleh, et al., 2005b).
Dispersion stability and transport of modified nanoiron in water-saturated porous media. Without surface
modification, RNIP particles rapidly flocculate and sediment from solution (Figure 4). Modification by each
polymer increased the stability of the suspensions relative to bare RNIP. The suspension stability increases as
the PSS block degree of polymerization increased from 462 to 650. Thus, the larger PSS block of PMAA^-
PMMAi7-PSS6so provided stronger electrosteric repulsions and better stability improvement than PMAA42-
PMMA26-PSS462, as would be expected for these polymers that are otherwise quite similar to each other. Parti-
cles modified with PSS homopolymer (PSS4S4) were more stable than bare RNIP, but less stable than the
triblock copolymers. It indicates that PSS homopolymer adsorbs to RNIP to some degree, but less effectively
than the triblock copolymers containing the PMAA anchor block. Polymer-modified nanoiron is significantly
more transportable than unmodified nanoiron, particularly at the high (3 g/L) concentrations needed for deliv-
ery into the subsurface (Figure 5). A systematic evaluation of the hydrogeochemical properties affecting trans-
port and targeting, including pH, I, and flow velocity, will be conducted.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
iJ'•*£"' *,ifvi>; _
dnTopptymer
•:y:'•"'"'••' ^f---f•••••-'••"-<•'•'"Ltrimodified
•0 Y. •.-• Y '.:•' 2000:;.Y " Y
'^Y-f:YYV
Figure 4. Sedimentation curves for bare and polymer-modified iron nanoparticle
dispersions (0.08 wt%) in water.
i-.
so
.40,
I Modified RNIP- ^
;" ^*»«>^.ji-^i
100
'•'•.".'•"^••:iiooo6
Figure 5. Effect of triblock copolymer modification on nanoiron transport in a 10 cm
sand-packed column.
References:
1. Zhang W. Nanoscale iron particles for environmental remediation: an overview. Journal of Nanoparticle
Research 2003;5:323-332.
2. Liu Y, Majetich SA, Tilton RD, Sholl DS, Lowry GV. TCE dechlorination rates, pathways, and efficiency
of nanoscale iron particles with different properties. Environmental Science and Technology 2005;39:
1338-1345.
3. Liu Y, Choi H, Dionysiou D, Lowry GV. TCE hydrodechlorination by amorphous monometallic nanoiron.
Chemistry of Materials 2005; 17:5315-5322.
4. Matyjaszewski K, Miller PJ, Shukla N, Immaraporn B, Gelman A, Luokala BB, Siclovan TM, Kickelbick
G, Valiant T, Hoffmann H, Pakula T. Polymers at interfaces: using atom transfer radical polymerization
in the controlled growth of homopolymers and block copolymers from silicon surfaces in the absence of
untethered sacrificial initiator. Macromolecules 1999;32:8716-8724.
5. Matyjaszewski K, Xia J. Atom transfer radical polymerization. Chemical Reviews 2001 ;101:2921-2990.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
6. Saleh N, Phenrat T, Sirk K, Dufour B, Ok J, Sarbu T, Matyjaszewski K, Tilton RD, Lowry 0V. Adsorbed
triblock copolymcrs deliver reactive iron nanoparticles to the oil/water interface. Nano Letters 2005;5(I2):
2489-2494.
7. Saleh N, Sarbu T, Sirk K, Lowry GV, Matyjaszewski K, Tilton RD. Oil-in-water emulsions stabilized by
polyelectrolyte-grafted nanoparticles. Langmuir 2005;21:9873-9878.
Success Stories
This research has been featured in the science news sections of several newpapers and technology Web sites.
"Tiny engineered particles could one day remove common pollutant," by Byron Spice, science and
technology writer for the Pittsburgh Post Gazette, in a feature article in the science and technology
section of the Gazette, April 1,2004 (http://www.post-gazette.com/pg/04092/294409.stm).
"Nanoparticles seek out solvents in groundwater," by Liz Kalaugher, editor ofNanotechWeb.org,
in a feature article in Nanotechweb.org on .April 13, 2004 (http://nanotechweb.org/articles/
news/3/4/8/1).
"Small science may clean a big problem," appeared in The Christian Science Monitor, Boston,
Thursday, February 10, 2005.
Special Treatment: Tiny technology tackles mega messes. Science News, April 23, 2005;67.
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Nanotechnology and the Environment; Applications and Implications Progress Review Workshop HI
Nanostructured Catalytic Materials for NOX Reduction
Using Combinatorial Methodologies
Selim Senkan
University of California-Los Angeles, Los Angeles, CA
Abstract
New advances in combinatorial methodologies are exploited for the discovery and optimization of nanostruc-
tured catalytic materials for the reduction of NOX under fuel lean combustion conditions. Recent developments
in automotive engineering have made possible the production of more fuel efficient—up to 25 percent—lean-
burning gasoline engines. The lack of appropriate catalytic technology to reduce NOX emissions under lean
burn conditions, however, impedes the commercialization of such engines. Although the existing three-way
catalysts allow for the effective control of CO, hydrocarbon (HC), and NOX emissions in current gasoline en-
gines that operate under stoichiometric conditions, they are ineffective in the presence of excess oxygen en-
countered in lean-burn engine exhausts. Therefore, the development of a new generation of catalysts that will
allow NOX control in oxygen-rich environments is urgently needed.
In the current program, libraries of catalytic materials were prepared by individually impregnating five support
materials of A12O3> CeO2, SiO2, Ti02, and Y-ZrO2 by salt solutions of 42 elements from the periodic table into
the resulting five different metal loadings. These support materials were used because of their durability in
harsh engine exhaust conditions. Catalytic materials were then tested for their NO reduction activities using
array channel microreactors and mass spectrometry. Overall, several thousand catalytic materials were pre-
pared and then tested at 1 atm pressure and in the temperature range 100 to 500 °C, and at a GSHV of 60,000
h"1. The feed gas used was 500 ppmv NO, 500 ppmv C3H6, 1,400 ppmv CO, 8 percent O2, 10 percent H2O, and
the balance helium. These test conditions realistically simulate the actual engine-out conditions, thereby ren-
dering the findings immediately relevant to automobile exhaust treatment catalysis. These systematic investi-
gations led to the discovery of Pt/TiO2 and Pt/SiO2 as the most significant leads, both of which exhibited supe-
rior performances, reducing the levels of NO by 25 percent and 20 percent, respectively.
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Nanotechnology and the Environment; Applications and Implications Progress Review Workshop III
A Bioengineering Approach to Nanoparticle-Based
Environmental Remediation
Daniel Strongin
Temple University, Philadelphia, PA
Abstract
Ferritin and ferritin-like protein can be used to assemble nanosized catalytic metal oxyhydroxide particles in
the size range of 1 to 8 nm. Horse spleen ferritin and Listeria innocua ferritin-like protein were used to assem-
ble Fe(O)OH particles ranging from 4 to 8 nm and 1 to 4 nm in diameter, respectively. Probe molecules were
used to investigate the surface reactivity of the nanoparticles assembled within ferritin, with and without the
surrounding protein, as a function of size. With regard to the latter circumstance, ferritin was deposited on an
Si support, dried, and exposed to oxidizing conditions to remove the protein shell. The reactivity of the sup-
ported nanoparticles toward environmentally relevant reactant showed a strong dependence with the particle
size and structure.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Nanoscale Bimetallic Particle for In Situ Remediation
Wei-xian Zhang
Lehigh University, Bethlehem, PA
Abstract
\
Hollow iron spheres with micro- and nano-scale pores were prepared using template-directed synthesis. Iron
nanoparticles were deposited on the surfaces of polymeric resin by reductive precipitation. The resin was sub-
sequently removed by heat treatment. Pores ranging in size from nanometers (-80 percent, <100 nm) to several
micrometers were observed on the shell. Specific surface area of the resulting iron spheres (0.4 mm dia.) was
2,100 m2/kg, that is 1,250 times bigger than the theoretical specific surface area of solid iron particles at the
same size. Tests further suggested that the iron spheres are effective for the reduction of several common envi-
ronmental pollutants, including azo dyes and chlorinated aliphatic compounds. Surface area normalized rate
for the reduction of trichloroethene was 17 percent higher than that of conventional microscale iron particles.
The reaction rate per unit of iron mass was approximately 1,461 times higher than that of solid iron particles at
the same size. The nanoporous iron has broad potential in groundwater remediation and industrial waste treat-
ment.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Nanostructured Catalysts for Environmental
Remediation of Chlorinated Compounds
Yunfeng Lu and Vijay T. John
Tulane University, New Orleans, LA
Abstract
This research is directed towards the development of novel mesoporous materials that act as supports for zero-
valent iron nanoparticles used in the breakdown of chlorinated compounds. Haiogenated organic compounds,
such as chlorinated aromatics, chlorinated aliphatics, and polychlorinated biphenyls, are typical of dense non-
aqueous phase liquids (DNAPLs) that are prevalent at contaminant sites. In recent years, the use of zerovalent
iron has represented a promising and innovative approach to the destruction of these compounds.1'2 Of particu-
lar interest is the number of publications recently that describe the use of nanoparticles of Fe in remediation
through hydrodechlorination. The enormous surface area of nanoparticles leads to enhanced efficiencies. Ad-
ditionally, the colloidal nature of Fe nanoparticles indicates that these materials may be pumped to contami-
nated sites. Alternatively, "runnel and gate" treatment systems may be devised where porous barriers of iron
particles are constructed in the path contaminated groundwater plumes.4
As a result of the high surface energy of nanoparticles, the particles tend to aggregate leading to larger units
that do not maintain colloidal stability. Although Fe nanoparticles may be superparamagnetic, if the particle
dimensions exceed 10-15 nm, they exhibit ferromagnetism and this also leads to aggregation and dropout of
solution. Finally, iron is hard to functionalize with organic compounds to attempt to maintain stability in aque-
ous or in organic systems.
The project's technical approach combines the simplicity and affordability of the sol-gel processing techniques
for ceramic synthesis with the efficiency and spontaneity of surfactant/silica cooperative assembly to manufac-
ture nanostructured decontamination materials using a simple aerosol processing technique.
Figure 1 schematically depicts the formation of nanostructured particles by the aerosol-assisted self-assembly
process.5 Starting with a solution of soluble silica and surfactant in ethanol/water solvent, the aerosol apparatus
atomizes the solution into droplets that undergo a drying and solidification step generating nanoparticles that
are collected in a filter. During this process, solvent evaporation enriches the surfactant and silicate from the
air-liquid interface of the droplet towards its interior, resulting in their co-assembly and in the formation of
nanostructures growing from the interface towards the interior. Subsequent condensation reactions of silica
during the drying and heating steps freezes the mesophases and results in nanostructured particles that exhibit
hexagonal, cubic, lamellar, or other nanostructures.
A wide variety of additives (e.g., metal ions, organic functional ligands, monomers, polymers, metal colloidal
particles, and catalyst particles) can be readily introduced to the surfactant/silicate solutions and incorporated
into the nanostructured particles. This method provides an extremely simple and efficient approach to synthe-
size various nanostructured composite particles. Figure 2 shows the representative transmission electron mi-
croscopy (TEM) images of nanostructured particles containing highly ordered hexagonal, cubic, or lamellar
pore channels, suggesting that porous nanostructured silica particles can be readily prepared using this ap-
proach.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
PARTICLE
COLLECTION
Self-assembly
from air/liquid Interface
Continuous self-numbly
Figure 1. Schematic of the formation of nanostructured particles
using the aerosol-assisted surfactant self-assembly.
Figure 2. Representative TEM images of hexagonal (Left), cubic (Center), and lamellar (Right)
nanostructured silica particles prepared using aerosol-assisted surfactant self-assembly.
Recent Results
The aerosolization technique employing surfactants as structure directing agents leads to the generation of
mesoporous ceramics. The idea was to incorporate iron precursors into the solution to be aerosolized with the
expectation that iron species would become entrapped in the silica particles. The hypothesis was that if zerova-
ient iron can be entrapped in porous silica nanoparticles, they would not aggregate. Furthermore, silica can be
surface functionalized quite easily to prepare particles that are hydrophobic or hydrophilic and stay sustained
in an aqueous or in an organic phase. Because silica is essentially inert, the composite would be expected to be
safe.
The results are extremely interesting. Shells of silica with zerovalent nanoparticles of iron were obtained. The
transmission micrographs of Figure 3 illustrate the results.
The continuing work seeks to test the efficiency of these materials in the breakdown of trichloroethylene. The
researchers are tremendously interested in studying the transport of these particles in pump-and-treat technolo-
gies. Research is underway to functionalize these materials so that they partition to the organic-water interface
or to the organic bulk phase for maximum efficiency.
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Nanotecknology and the Environment: Applications and Implications Progress Review Workshop III
Figure 3. TEMs of aerosolized silica particles containing zerovalent iron nanoparticles.
References: '
1. Gillham RW. In: Aral MM, eds. Advances in Groundwater Pollution Control and Remediation. Dordrecht,
The Netherlands: Kluwer Press, 1996.
2. Tratnyek PG. Putting corrosion to use: remediation of contaminated groundwater with zero-vaJent metals.
Chemistry and Industry (London) 1996;13:499-503.
3. Wang C-B, Zhang W-X. Nanoscale metal particles for dechlorination of PCE and PCB. Environmental
Science and Technology 1997;31:2154.
Ponder SM, Darah JG, Mallouk TE. Remediation of Cr(VI) and Pb(II) aqueous solutions using supported,
nanoscale zero-valent iron. Environmental Science and Technology 2000;34(l2):2564-2569.
Ponder SM, Darab JG, Bucher J, Caulder D, Craig I, Davis L, Edelstein N, Lukens W, Nitsche H, Rao L,
Shuh DK, Mallouk TE. Surface chemistry and electrochemistry of supported zerovalent iron nanoparticles
in the remediation of aqueous metal contaminants. Chemistry and Materials 2001 ;13:479-486.
Schrick B, Blough JL, Jones D, Mallouk TE. Hydrodechlorination of trichloroethylene to hydrocarbons
using bimetallic nickel-iron nanoparticles. Chemistry and Materials 2002;14:5140-5147.
4. Starr RC, Cherry JA. In situ remediation of contaminated groundwater. Ground Water 1994;32:465.
5- Lu Y, Fan H, Stump A, Ward TL, Reiker T, Brinker CJ. Aerosol-assisted self-assembly of mesostructured
spherical nanoparticles. Nature 1999;398:223-226.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Nanostructured Materials for Environmental
Decontamination of Chlorinated Compounds
Yunfeng Lu and Vijay T. John
Tulane University, New Orleans, LA
Environmental Implication/Application
Non-aqueous phase liquids (NAPLs) are substances such as oils, solvents, gasoline, and any organic substance
that is sparingly soluble in water. NAPLs can be divided into two types: ones that are lighter than water (light
non-aqueous phase liquids, or LNAPLs) and ones that are denser than water (dense non-aqueous phase liquids,
or DNAPLs). DNAPLs are of particular concern because they are denser than water, have very low solubility,
and can persist in groundwater sources for long periods of time, eventually making their way into drinking
water sources.1 When DNAPLs enter groundwater, they are hard to remove and may be pushed deeper into
aquifers by removal attempts. The ability of treatment methods to break down the aquifer-trapped NAPL in a
safe and effective manner becomes of utmost importance.
Halogenated organic compounds such as chlorinated aromatics, chlorinated aliphatics, and polychlorinated
biphenyls are typical of DNAPLs that are prevalent at contaminant sites. In recent years, the use of zerovalent
iron has represented a promising and innovative approach to the destruction of these compounds.2'3 Of particu-
lar interest is the number of publications recently that describe the use of nanoparticles of Fe in remediation
through hydrodechlorination. The enormous surface area of nanoparticles leads to enhanced breakdown effi-
ciencies. Additionally, the colloidal nature of Fe nanoparticles indicates that these materials may be pumped to
contaminated sites. Alternatively "funnel and gate" treatment systems may be devised where porous barriers of
iron particles are constructed in the path of contaminated groundwater plumes.5
However, there are difficulties with the use of iron nanoparticles. Due to the high surface energy of nanoparti-
cles, the particles tend to aggregate leading to larger units that do not maintain colloidal stability. Although Fe
nanoparticles may be superparamagnetic, if the particle dimensions exceed 10-15 nm, they exhibit ferromag-
netism and this also leads to aggregation and dropout of solution. Finally, iron is hard to functionalize with
organic compounds to attempt to maintain stability in aqueous or in organic systems.
This project directly addresses these issues through the development of a novel carrier for iron nanoparticles.
Mesoporous silica nanoparticles are being developed into which zerovalent iron can be trapped. The following
are specific advantages of the technology with environmental implications:
• Silica is innocuous in the environment, and the composite with zerovalent iron also is expected to be to-
tally innocuous.
• This research should result in the design of zerovalent iron carriers that can be positioned at the organic-
water interface or in the bulk organic phase. The researchers are able to prepare holiow silica nanoparticles
where the low density will prevent settling out of the carriers during in situ soil treatments.
• The easy functionalization of these carriers should allow greater flexibility in the transport and partitioning
of the zerovalent iron.
This research will result in the development of inexpensive and effective nanparticles for the in situ degrada-
tion of chlorinated organics.
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Nanotechnology and the Environment: Applications anil Implications Progress Review Workshop III
References:
1. Cowell M, Kibbey T, Zimmerman J, Hayes K. Partitioning of ethoxylated nonionic surfactants in wa-
ter/NAPL systems: effects of surfactant and NAPL properties. Environmental Science and Technology
2000;34(8): 1583-1588.
2. Gillham RW. In: Aral MM, Ed. Advances in Grottundwater Pollution Control and Remediation. Dor-
drecht, The Netherlands: Kluwer Press, 1996.
3. Tratnyek PG. Putting corrosion to use: remediation of contaminated groundwater with zero-valent metals.
Chemistry and Industry (London) 1996;13:499-503.
4. Wang C-B, Zhang W-X. Nanoscale metal particles for dechlorination of PCE and PCB. Environmental
Science and Technology \ 997;31:2154.
Ponder SM, Darah JG, Mallouk TE. Remediation of Cr(VI) and Pb(II) aqueous solutions using supported,
nanoscale zero-valent iron. Environmental Science and Technology 2000;34(12):2564-2569.
Ponder SM, Darab JG, Bucher J, Caulder D, Craig I, Davis L, Edelstein N, Lukens W, Nitsche H, Rao L,
Shuh DK, Mallouk TE. Surface chemistry and electrochemistry of supported zerovalent iron nanoparticles
in the remediation of aqueous metal contaminants. Chemistry and Materials 2001;13:479-486.
Schrick B, Blough JL, Jones D, Mallouk TE. Hydrodechlorination of trichloroethylene to hydrocarbons
using bimetallic nickel-iron nanoparticles. Chemistry and Materials 2002; 14:5140-5147.
5. Starr RC, Cherry JA. In situ remediation of contaminated groundwater. Ground Water 1994;32:465.
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A
Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Synthesis and Application of a New Class of Stabilized
Nanoscale Iron Particles for Rapid Destruction of
Chlorinated Hydrocarbons in Soil and Groundwater
Dongye (Don) Zhao
Auburn University, Auburn, AL
Abstract
The overall goal of this research project is to develop a cost-effective, in situ remediation technology that em-
ploys a new class of highly dispersible iron-based nanoparticles for the rapid destruction of chlorinated hydro-
carbons in soil and ground-water. The specific objectives are to: (1) synthesize a new class of stabilized iron-
based nanoparticles using low-cost and "green" stabilizers such as starches and celluloses; (2) test the effec-
tiveness of the stabilized nanoparticles for dechlorination of select contaminants (tetrachloroethylenes and
polychlorinated biphenyls) in soil and groundwater; and (3) test the feasibility of an in situ remediation process
that is based on the nanoparticles.
The preliminary data showed that a water-soluble or sodium carboxymethyl cellulose can serve as the dispers-
ant to effectively stabilize palladized iron (Fe-Pd) nanoparticles. Compared to non-stabilized Fe-Pd particles,
the stabilized nanoparticles displayed markedly improved physical stability, soil dispersibility, chemical reac-
tivity, and reactive longevity. Column tests showed that the stabilized nanoparticles can be readily dispersed in
a loamy-sand soil and then be recovered completely. Batch dechlorination tests demonstrated that the starch-
stabilized nanoparticles degraded TCE 37 times faster than non-stabilized counterparts based on the pseudo
first-order rate constant.
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Nanosensors for Detection of Aquatic Toxins
Robert E, Gawley ,
University of Miami, Coral Gables, FL
Abstract
The objectives of this research project are to design and prepare nanoscale sensors for the detection of marine
toxins domoic acid, brevetoxin, ciguatoxin, cylindrospermopsin, and tetrodotoxin. Most of these marine toxins
bind specifically to protein receptor sites with a high affinity (Kd typically in the nm range). The protein recep-
tor sites for several of these toxins have been'characterized, and include two characteristic features. One is an
array of amino acid side chains that complement structural features of the toxin, which facilitates and strength-
ens binding of the toxin into the receptor site. A second feature is a solvent-excluded pocket in. which the
amino acid side chains are arrayed. This preorganized feature of toxin receptor sites will be mimicked by de-
sign of synthetic receptors at the nanoscale (nanosensors). To optimize the sensitivity and the selectivity of the
nanosensor, combinatorial synthesis techniques will be employed to optimize binding in libraries of peptidic
host molecules immobilized on solid support (polystyrene beads). Unlike side chain arrays in the native (pro-
tein) receptors, this 'study will not be limited to L-amino acids, or even to natural amino acids. In this way,
short peptide sequences will be produced that wrap around toxins and bind them by providing an array of side
chains similar to the native receptor. To mimic the solvent-excluded pocket of protein receptor sites, the com-
binatorially designed peptide will be incorporated at the core of a dendritic polymer, still on a solid support.
The marriage of combinatorial design and dendrimer synthesis on solid support will provide large libraries (up
to 100,000 members) of polypeptide hosts inside dendritic polymers, with each individual host molecule at-
tached uniquely to a polystyrene bead. This is a novel approach in nanosensor design. To our knowledge, this
is the first time combinatorially designed peptidic hosts have been incorporated into a dendrimer. Qualitative
evaluation of toxin binding can be done simply with a fluorescence microscope. Quantitative analysis will be
done with a specific host after it has been synthesized in bulk.
At present, environmental monitoring for aquatic toxins is most commonly done by mouse bioassay. Alterna-
tive methods, such as liquid chromatography coupled with mass spectroscopy (LC-MS), are extraordinarily
expensive and not suitable for high-throughput analysis. To move away from mouse bioassay, an inexpensive,
fast method is needed. This project will identify nanoscale sensors attached to polystyrene beads that can de-
tect toxins using only a hand-held UV lamp and a magnifying glass. The science behind the design of toxin
sensors will lead to further developments as well. These synthetic receptors also could be used to immobilize
the toxins. Although beyond the scope of the present work, the same design features to be used for mimicking
toxin receptor sites also can be used to mimic enzyme receptor sites. Thus, by using models of enzyme active
sites, we anticipate being able to use this methodology to mimic enzyme reactions to produce solid-phase cata-
lysts.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Neuromorphic Approach to Molecular Sensing With
Chemoreceptive Neuron MOS Transistors (CvMOS)
Edwin C. Kan and Bradley A. Minch
Cornell University, Ithaca, NY
Abstract
An ideal microsensor for autonomously monitoring chemical and molecular environmental hazards in both
water and air should simultaneously have a high sensitivity, a high selectivity, a large dynamic range, a low
manufacturing cost, simple calibration/reset protocols, a long lifetime, field reconfigurability, and low power
consumption. These requirements arise from considering the rapid deployment and autonomous operation of a
microsensor network monitoring a large area. The researchers have developed a Si-based neuron MOS transis-
tor with a novel extended floating-gate structure that permits molecular/chemical sensing. The sensor, called a
chemoreceptive neuron MOS (CvMOS) transistor, is expected to simultaneously meet all of these require-
ments, and can be fabricated by minor modification or simple postprocessing of conventional CMOS inte-
grated circuits. The modular structure and fabrication of this new device permits us to use CMOS devices op-
timized for high sensitivity and large dynamic range and affords us complete flexibility in the design and com-
position of the molecular/chemoreceptive sites. The performance of this new sensor has proved to be vastly
superior to that of existing chemical microsensors, such as the ion-sensitive FET (ISFET) and the CHEMFET,
in nearly every important respect resulting from the internal transistor gain, no need for a liquid reference po-
tential, and much better isolation between the electronics and microfluidics. During the first half of the project
period, selectivity between species like Na+ and K+ has been demonstrated with various nonfunctionalized
polymer finger coatings. Modification of contact angles in the microfluidic channel interface, sensitive to the
ionic strength and species, also has been demonstrated.
The preliminary process flow and testing of CvMOS transistors with generic molecular receptive areas for va-
por and liquid sensing (e.g., water, acetone, etc.) already have been established. The preliminary measure-
ments have validated most of our assumptions on the performance of these devices. In the 3-year proposed
effort, prototype arrays will be fabricated of these novel microsensors with various molecular/chemoreceptive
surface coatings, and their sensitivities will be characterized. Surface adsorption kinetics will be studied to fa-
cilitate fast and reliable coating selection. This study will start with polymer coatings that have been used in
vapor and liquid sensors through volume expansion monitoring. A new table of target agents and coatings will
be gathered from CvMOS reading to achieve selectivity. Also, a micropower neuromorphic electronic inter-
face will be developed for such sensor arrays whose structure and function is based on what is known about the
olfactory and gustatory sensory systems of animals. This interface, called the silicon olfactory bulb, will pro-
vide a distilled set of informative features that can be used by a recognition system to perform analysis and risk
assessment. During the first half of the project period, integrated sensing analog circuits have been demon-
strated to distinguish species and concentration without the use of the fluid potential. The required analog cir-
cuit can be implemented on the same foundry chip with CvMOS.
A complete system, including both a sensor array and the silicon olfactory bulb, will be developed that can be
fully integrated, perhaps on a single chip, and that will dissipate only a few hundred microwatts of power in
total. Such devices could be manufactured in large numbers very inexpensively and deployed rapidly as envi-
ronmental sensors, running autonomously for long periods of time on either solar power or miniature chemical
batteries. During the first half of the project period, the characteristics of CvMOS have been demonstrated in
the proof-of-concept manner for sensitivity, selectivity, power consumption, and system integrability with
CMOS technology and circuits. The developed CvMOS sensor with its all-around sensor specification for an
autonomous microsystem deployment can bring great benefit to the environmental sensing in a wide deploy-
ment mode. The new sensor is inexpensive to be integrated with other necessary electronics for data processing
and communication (on the same chip), and can achieve a wide range of selectivity and sensitivity. It is ready
for product development to target at specific chemicals or molecules in ocean or in air.
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Compound Specific Imprinted Nanospheres for Optical Sensing
Barry K. Lavine
Oklahoma State University, Stillwater, OK
Abstract
The use of molecularly imprinted polymers is being investigated as the basis of a sensitive and selective sens-
ing method for the detection of pharmaceutical and other emerging organic contaminants, which are at parts
per billion levels, in aquatic environments. Moderately crosslinked molecularly imprinted polymeric micro-
spheres (ca. 1 micron in diameter), which are designed to swell and shrink as a function of analyte concentra-
tion in aqueous media, have been prepared. These microspheres are incorporated into hydrogel membranes.
Chemical sensing is based on changes in the refractive index of the membrane that accompanies swelling of
the molecularly imprinted microspheres. These changes are measured by surface plasmon resonance (SPR)
spectroscopy. For SPR, the polymer microspheres are directly applied to a gold surface where they are held in
place by electrostatic attraction. Encapsulation of the polymeric microspheres is achieved by micropipetting
the membrane formulation onto the surface of the SPR substrate, where it is distributed across the gold surface
by spatula prior to polymerization.
The prototype SPR sensor is both sensitive and specific. The addition of as little as 1.0 x 10"7 M theophylline is
sufficient to cause a change in the refractive index of the membrane, which was detected by SPR. Higher con-
centrations of theophylline produced a larger change in refractive index. In contrast, the same membrane
showed no response to 1.0 x 10"* M caffeine. (Caffeine and theophylline differ by only a single methyl group.)
This result, we believe, is significant for two reasons. First, selectivity has been introduced into SPR analyses
using these membranes. Studies where biological receptors have been used to functionalize gold (Au) or silver
(Ag) surfaces with analyte specific receptors for pollutant monitoring have often been unsuccessful due to
problems associated with antigen stability and crossreactivity. Second, the likelihood is high that parts per bil-
lion detection limits for theophylline and other so-called emerging organic contaminants can be achieved with
this approach to chemical sensing once the polymeric formulation used to develop the imprinted polymer and
hydrogel membrane are optimized. Currently, a polymer formulation is being used, which was developed from
N-isopropylacrylamide or N-N-propylacrylamide (transduction monomer), methacrylic acid (recognition
monomer), and moderate concentrations of methylenebisacrylamide (crosslinker), and a template to prepare
molecularly imprinted polymers that swell in the presence of the targeted analyte. However, the concentration
of the recognition monomer is probably too high. Furthermore, the thickness of the membrane is approxi-
mately 75 mm, and the size of the microspheres is approximately 800 nm. The membrane needs to be thinner
to minimize diffusion distances, ensuring facile mass transfer. Smaller microspheres (approximately 200 nm)
will mean that a larger number of polymer particles can be immobilized on the Au surface, and the entire parti-
cle will lie within the region of the evanescent wave.
The proposed technology has several important advantages for chemical sensing. The hydrogel membrane can
serve as a "filter" to block out larger molecules (e.g., humic acid that might otherwise foul the microspheres).
Another advantage of this approach to sensing is that it can be implemented at any wavelength. The micro-
spheres are stable. They are not subject to photodegradation and can undergo multiple swelling and shrinking
cycles without degrading. Furthermore, swelling and shrinking of the microspheres has a minimal effect on the
size of the hydrogel, and does not generate enough force to affect adhesion of the hydrogei to a substrate. By
comparison, previously reported approaches to chemical sensing that involve polymer swelling share the
common feature that swelling introduces stress, causing the polymer to crack and tear as well as delaminate.
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Advanced Nanosensors for Continuous
Monitoring of Heavy Metals
OmowunmiA. Sadik, Joseph Wang, Ashok Mulchandani, Isaac Kowino,
Jason Karasinki, Marcells Omole, and Daniel Andreescu
State University of New York at Binghamton, Binghamton, NY
Abstract
The overall objective of this research project is to incorporate novel, colloidal-metal nanoparticles into a bed of
electrically conducting polymers, and then use these for the development of nanosensors. During the first year
of the project, the feasibility of designing advanced conducting polymeric materials for sensing and remedia-
tion applications was explored. These include the synthesis of: (1) polyamic acid-silver nanoparticle compos-
ite membranes, (2) polyoxy-dianiline films, and (3) electrochemical deposition of gold nanoparticle films onto
functionalized conducting polymer substrates. These were characterized using electrochemical and surface
morphology techniques, including TEM, AFM, CV, and FTIR. The summary of the synthetic efforts has been
published in Langmuir and the Journal of Electrochemical Society.
The highlight of second year of this project is the development of a palladium (Pd) synthetic approach that was
tested as an environmental catalyst for the conversion of hexavalent chromium [Cr(VI)J to trivalent chromium
[Cr(IH)}. One of the synthetic nanostructured materials developed in the first year of the project was selected
and tested as an environmental catalyst for the conversion of higher valent to low valent Cr in soil and water
samples. Chromium exists in the environment mainly in two different oxidation states: Cr(III) and Cr(VI).
Although Cr(III) is considered a nutrition supplement for regulating normal bodily functions, Cr(VI) is a po-
tential carcinogen with remarkable harmful effects on both plants and animals. Currently, Cr(VI) is converted
to Cr(III) using chemical assay formats such as wet acid digestion, which are usually labor intensive and re-
quire the use of hazardous chemicals. Therefore, there is a need to design novel Cr(VI) remediation approaches
that are safe, fast, and can efficiently convert Cr{VI) to Cr(IH).
The application of nanoparticles could be used to address such needs due to their relatively large surface areas
that allow for high reactivity rates. There is, however, little or no information regarding the application of pal-
ladium-nanoparticles (Pd-NPs) in the conversion-of Cr(VI) to Cr(IlI) in soils and aqueous media. The real
sample application of the Pd nanoparticles-sulfur mixture tested using soil samples produced more than 92
percent conversion in the presence of Pd-NPs/S within 1 hour. In contrast, only 33 percent of the same concen-
tration was converted to Cr(III) in the absence of Pd-NPs/S. This represents more than a 500-fold improvement
in conversion rate as compared to current microbial approaches. This work offers a new and safe application of
nanotechnology for the reduction of high oxidation state heavy metal pollutants. In addition, the researchers
have reported the use of Bismuth electrodes for sensing.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Ultrasensitive Pathogen Quantification in Drinking Water Using
High Piezoelectric PMN-PT Microcantilevers
Wan Y. Shih and Wei-Heng Shift
Drexel University, Philadelphia, PA
Abstract
Highly piezoelectric cantilevers offer the advantages of simple electrical detection and better capabilities to
withstand damping in water. It is especially suitable for in situ aqueous detection of bioagents or microbes.
Binding of antigens to the antibody immobilized on the cantilever surface increases the cantilever's mass and
reduces its resonance frequency, which is detected by monitoring the resonance frequency shift. Detection of
cells, proteins, and specific antigen-antibody binding has been demonstrated with a lead zirconate titanate
(PZT)/stainless steel cantilever. In addition, we have shown that detection sensitivity increased with a de-
creasing cantilever size, L, as L"4. In this project, we have pursued both: (1) developing highly piezoelectric
lead magnesium niobate-lead titanate (PMN-PT) microcantilevers for better detection sensitivity; and (2) in-
vestigating in situ detection of water-born pathogens such as Salmonella typhimurium.
With PZT/glass cantilevers of less than 0.5 millimeter in length, we have: (1) achieved better than 3x10""
g/Hz mass detection sensitivity; (2) obtained resonance frequency shifts 3-7 times higher than those of a 10
MHz quartz crystal microbalance (QCM) in the same test conditions; and (3) demonstrated better than 104
cells/mL concentration detection sensitivity exceeding the infectious dosage of S. typhimurium (105 cells/mL)
and the concentration detection limit of commercial ELISA assays (10 cells/mL). Detection selectivity was
illustrated between Salmonella and yeast.
For PMN-PT microcantilever fabrication, an innovative low-temperature approach was developed to synthe-
size freestanding lead magnesium niobate-lead titanate (PMN-PT) films as thin as 20 um thick with piezo-
electric properties better than those of specially-cut single crystals. After electroplating 4-um thick Cu, PMN-
PT/Cu microcantilevers were made by wire-saw cutting. With a 600 um length, PMN-PT/Cu microcantilevers
were shown to exhibit better than 10"2 g/Hz (less than the mass of a single cell) mass detection sensitivity. It is
expected that further reducing the cantilever length to less than 100 um will achieve better femtogram sen-
sitivity.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Low-Cost Organic Gas Sensors on Plastic for Distributed
Environmental Monitoring
Yivek Subramanian
University of California, Berkeley, CA
Abstract
The ability to monitor various chemical species in large expanses of currently unmonitored land resources will
enable proactive response to environmental problems and also will assist in the development of more accurate
models of environmental phenomena. Unfortunately, the widespread deployment of chemical sensors is gener-
ally economically unfeasible using currently available sensor technology, primarily because individual sensors
are too expensive to be deployed on such large scales.
In recent years, there has been tremendous interest in organic transistors as a means of realizing ultralow-cost
electronics, particularly because they may potentially be printed at extremely low cost on cheap substrates such
as plastic and paper. More recently, several groups have demonstrated that organic transistor channels show
tremendous environmental sensitivity, though they usually lack specificity. Specificity may be achieved using
arrays of organic transistors with different channel materials, thus generating unique, highly specific signatures
on chemical exposure. Because such devices may be formed entirely by solution-based processing techniques,
including inkjet printing, these are an attractive means of realizing low-cost gas sensors for environmental
monitoring.
Our success in realizing such a sensor technology will be reported, and our development of arrayed sensors
based on organic transistors will be described. The repeatability and robustness of the same are being studied
as well as their usability in the detection of environmental contaminants, with the initial focus aimed at organic
solvents often used in industrial applications. Initial results indicate that robust, albeit slow, cycling of organic
sensors for reliable detection of several solvents is highly possible. This is promising, as most environmental
monitoring applications will not require high-speed responses. Also, simultaneous differential sensing of vari-
ous chemicals will be demonstrated, thus establishing the potential of these sensors in electronic noses.
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NanotechnoloKy and the Environment: Applications and Implications Progress Review Workshop III
A Nanocontact Sensor for Heavy Metal Ion Detection
Nongjian Too
Arizona State University, Tempe, AZ
Abstract
Because of the toxicity of heavy metal ions to a broad range of living organisms, including humans, and the
fact that these pollutants are nonbiodegradable, there is an urgent demand for an in situ sensor that is sensitive
enough to monitor heavy metal ions before the concentration reaches a dangerous level. The researchers have
been developing an integrated sensor chip to meet such demand. The sensor chip consists of an array of nano-
scale sensing elements. Three different sensing elements (nanocontacts, molecular junctions, and polymer
nanojunctions) were fabricated. Metal ion detections using these sensing elements were demonstrated. In addi-
tion to metal ions, these sensing elements also are capable of detecting a variety of other chemical and biologi-
cal species. This research project's goal is to develop a highly integrated sensor for simultaneous detection of a
range of different chemical species.
Nanocontacts. This sensor starts with an array of electrode pairs fabricated on a silicon chip. The separation
between the two electrodes in each pair is as small as a few nm (Figure 1). When the electrodes are exposed to
a solution containing heavy metal ions, the ions can be deposited into the gap by controlling the electrode po-
tentials. Once the deposited metal bridges the gap, a sudden jump in the conductance between the electrodes
occurs, which can be easily detected. Because the gap can be made as narrow as a few nm or less, the deposi-
tion of even a few ions into the gap is enough to trigger a large change in the conductance, thus providing a
sensitive detection of metal tons. Previous experiments have shown that the conductance of such a small bridge
is quantized and given by NGO, where N is an integer and GO is conductance quantum (=2e2/h, e is the elec-
tron charge and h is the Planck constant). For this reason, the bridge is often called quantum point contact. The
metal bridge also can be stripped off (or dissolved) by sweeping the potential anodically. The potentials at
which deposition and dissolution take place provide identity of the metal ions, a principle similar to that of
anodic stripping analysis. This nanocontact sensor is simple and can sensitively and selectively detect heavy
metai ions, but it is limited to metal ions. To detect other environmentally important species with the same sen-
sor chip, two other sensing elements, molecular junctions and conducting polymer junctions on the sensor chip
(described below), have been added.
Molecular Junction. Molecular junctions have been fabricated by bridging the narrow gaps of the electrodes
described above with molecules, which allows us to directly measure the conductance of the molecules (Figure
2). To demonstrate metal ion detections, peptides with different sequences were chosen to bridge the gap.
When a metal ion binds onto the peptides, a change in the conductance is detected. The metal ion-induced
conductance change is sensitive to the sequence of the peptides. By selecting appropriate sequences, different
metal ions on the peptides can be detected. Metal ion binding was studied on short peptides, and a conductance
increase was observed in each case. The conductance increase is highly sensitive to the sequence of the pep-
tide. For example, the binding of a Cu2+ onto cysteamine-Cys causes only a 10 percent conductance increase,
but the binding onto cysteamine-Gly-Gly-Cys increases the conductance approximately 300 times. Therefore,
the peptide sequence can be tuned to maximize the metal-ion binding-induced conductance change for sensor
applications. The conductance change also is dependent on the type of metal ions. For example, the binding of
Ni onto cysteamine-Gly-Gly-Cys increases the conductance approximately 100 times, which is several times
smaller than the case of Cu2+ binding. This metal ion dependence shows that different metal ions can be identi-
fied from the conductance measurement, even if they all bind to the peptide.
Conducting Polymer Junctions. Because most molecules are not good conductors, the molecular junction ap-
proach is limited to relative small molecules (Figure 2). To detect large biologically relevant molecules, the
gap between the nanoelectrodes was bridged with conducting polymers to form a metal-polymer-metal junc-
tion. For selective detection of a particular target species, appropriate probe molecules were attached onto the
polymers such that a specific binding of the target species onto the probe molecules is detected as a change in
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
the conductance of the polymer junction. For metal ion sensor applications, oligopeptides were attached to the
polymer junctions via peptide bonds. One example is to attach Gly-Gly-His to a polyaniline junction. The
tripeptide was chosen because of its large binding constant for copper ions. When exposing the sensor to other
metal ions, little response was detected, which shows the high degree of selectivity. The experiment demon-
strates the feasibility of detecting metal ions using the polymer junctions.
metal ions ,
;SIN
" "- V *tf-
Figure 1. (A) A drop of sample solution is placed onto a pair of nanoelectrodes
separated with an atomic scale gap on a silicon chip. (B) Holding the nanoelec-
trodes at a negative potential, electrochemical deposition of a single or a few
metal atoms into the gap can form a nanocontact between the two nanoelectrodes
and result in a quantum jump in the conductance.
Figure 2. (A) A molecular junction is formed by bridging a pair of nanoelectrodes with
molecules terminated with linker groups that can bond to the nanoelectrodes co-
valently, (B) Bridging the nanoelectrodes with conducting polymers results in
polymer junctions. By attaching different molecular probes onto the polymers,
specific interactions between a target species and the molecule probes are de-
tected as a change in the conductance of the polymer junction.
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Nanotechnologyand the Environment: Applications and Implications Progress Review Workshop 11 J
Nanomaterial-Based Microchip Assays for Continuous
Environmental Monitoring
Joseph Wang
Arizona State University, Tempe, AZ
Abstract
This research project will address the needs for innovative nanotechnological tools for continuous environ-
mental monitoring of priority pollutants. The objective of this project is to create a novel nanomaterial-based
submersible microfluidic device for rapidly, continuously, and economically monitoring different classes of
priority pollutants. The unique properties of metal nanoparticles and carbon nanotubes will be exploited for
enhancing the separation and detection processes, respectively, in microchip environmental assays, and to un-
derstand the relationship between the physical and chemical properties of these nanomaterials and the observed
behavior. The miniaturized "Laboratory-on-a-Cable" will incorporate all of the steps of the analytical protocol
into the submersible remotely deployed device.
This project will address the challenge of transforming the "Lab-on-a-Chip" concept to an effective environ-
mental monitoring system and will exploit the unique properties of nanomaterials for enhancing such chip-
based environmental assays. "Lab-on-a-Chip" technologies can dramatically change the speed and scale at
which environmental analyses are performed. The ultimate goal of this project is to develop a submersible mi-
crofluidic device, based on the integration of all the necessary sample handling/preparatory steps and nano-
material-based assays on a cable platform. The new "Laboratory-on-a-Cable" concept relies on the integration
of continuous sampling, sample pretreatment, particle-based separations, and a nanotube-based detection step
into a single-sealed miniaturized submersible package. Nanoparticle and nanotube materials will be examined
toward the enhancement of the separation and detection processes, respectively. Factors governing the im-
provements imparted by these nanomaterials will be identified, and structural-performance correlations will be
established. New "world-to-chip" interfaces will be examined toward the goal of effective online sample intro-
duction, and will assess the challenges of transforming the new microchip to a continuous monitoring system.
The parameters governing the microchip behavior will be optimized, and the analytical performance will be
characterized and validated.
This research project will enhance the understanding of the use of nanoparticles and carbon-nanotubes as sepa-
ration carriers and detectors, respectively, in chip-based environmental assays. The resulting submersible mi-
crofluidic device will enable transporting the entire laboratory to the sample source, and will offer significant
advantages in terms of speed, cost, efficiency, sample/reagent consumption, and automation. Performing in
situ all of the necessary steps of the analytical protocol should have an enormous impact on the way contami-
nated sites are monitored. Such development of a miniaturized system, with negligible waste production, holds
great promise for meeting the requirements of field "Green Analytical Chemistry."
Understanding the correlation between the properties of nanomaterials and the measurement processes will
have broader implications on the use of nanomaterials in analytical chemistry, on the fields of microfluidic
devices, and on nanotechnology, in general.
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Conducting-Polymer Nanowire Immunosensors
Array for Microbial Pathogens
Ashok Mulchandani
University of California-Riverside, Riverside, CA
Abstract
A promising approach for the direct (label-free) electrical detection of biological macromolecules uses one-
dimensional (1-D) nanostructures such as nanowires and nanotubes, configured as field-effect transistors that
change conductance upon binding of charged macromolecules to receptors linked to the device surfaces. Com-
bined with simple, rapid, and label-free detection, potentially to a single molecule, these nanosensors are also
attractive due to the small size, low power requirement and, most of all, the possibility of developing high*
density arrays for simultaneous analyses of multiple species. Although current nanosensors based on carbon
nanotubes and silicon nanowires have elucidated the power of 1-D nanostructures as biosensors, they have low
throughput and limited controllability and are unattractive for fabrication of high-density sensor arrays. More
importantly, surface modifications, typically required to incorporate specific antibodies, have to be performed
postsynthesis and postassembly, limiting the ability to individually address each nanostructured sensing ele-
ment with the desired specificity.
The overall objective of this research project is to develop a novel technique for the facile fabrication of biore-
ceptor (antibody)-functionalized nanowires that are individually addressable and scalable to high-density bio-
sensor arrays and to demonstrate its application for label-free, real-time, rapid, sensitive and cost-effective de-
tection of multiple pathogens in water. Electropolymerization of conducting polymers between two contact
electrodes is a versatile method for fabricating nanowire biosensor arrays with the required controllability. The
benign conditions of electropolymerization enable the sequential deposition of conducting-polymer nanowires
with embedded antibodies onto a patterned electrode platform, providing a revolutionary route to create "truly"
high-density and individually addressable nanowire biosensor arrays. The nanowire immunosensor array's
utility will be used to simultaneously quantify three important model pathogens: poliovirus, hepatitis A virus
(HAV) and rotarvirus.
The researchers recently reported (Ramanathan et al., 2004) simple, yet powerful, facile technique of electro-
chemical polymerization of biomolecule-friendly conducting polymers, such as polypyrrole, will be conducted
in prefabricated channels of tailor-made aspect ratio between two contact electrodes at a site-specific position
to synthesize nanowires of tailor-made properties for fabricating individually addressable high-density
nanowire biosensor arrays. Detection of pathogens will be achieved by the extremely sensitive modulation of
the electrical conductance of the nanowires brought about by the change in the electrostatic charges from bind-
ing of the pathogens to the antibodies.
The effects of monomer concentration, dopant type and concentration, aspect ratio, and electrochemical po-
lymerization mode on the sensitivity, selectivity, and durability of poliovirus, HAV, and rotavirus antibodies-
functionalized polypyrrole nanowires as label-free bioaffinity sensors of these important model viral pathogens
in water will be investigated to establish optimum synthesis conditions of biomolecules-functionalized
nanowires to successfully realize this innovation to practice.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Exploring the Impact of a Nanostructure's Size and Shape
on Cellular Uptake, Clearance, and Metabolism
Warren Chan
University of Toronto, Toronto, Ontario, Canada
Abstract
Novel discoveries on molecular differences between diseased and healthy cells and tissues, and the develop-
ments of nanotechnology probes and tools are transforming the way we treat and diagnose disease. Biological
molecules provide a means to direct nanostructures to a diseased site where the nanostructure can be optically,
electrically, or magnetically lit up or treat the diseased site. A key to this hybrid research field is the ability to
engineer nanostructures with defined properties. Essentially, a nanostructure provides a system that has cus-
tom-tunable function based on its size and shape. Recently, these researchers and others have demonstrated the
use of such nanostructures for cell, tissue, and animal imaging and therapeutic applications for the early detec-
tion and treatment of cancer. The interface of these two fields has prompted the need to address several impor-
tant questions. These questions include: Are the nanostructures toxic? How does a cell process these nano-
structures? What is the fate and clearance of these nanostructures? Are these processes related to the dimen-
sional or surface chemical characteristics of the nanostructures? These fundamental questions must be an-
swered before nanostructures become useful for clinical applications. The results from this research project
provide guidance for the design of nanostructures for biomedical applications.
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Section 6. Treatment
Cost-effective treatment of pollutants poses a challenge for EPA and others in the development of effective
risk management strategies. EPA supports research that addresses new treatment approaches that are more
effective in reducing contaminant levels and more cost effective than currently available techniques. A variety
of pollutants at different concentrations requiring removal may exist at contaminated sites, in groundwater, or
in process fluids. Nanotechnology offers the possibility of more effective treatment of gases, soil, and water
due to the higher surface to volume ratios of nanomaterials. In addition, collection and separation mechanisms
may be more effective due to unique physical properties at the nanoscale. Specific control and design of ma-
terials at the molecular level may impart increased affinity, capacity, and selectivity for pollutants.
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Nanotechnology and the Environment: Applications and implications Progress Review Workshop III
Applications of Nanoscale Tunable Biopolymers
for Heavy Metal Remediation
Ashok Mulchandani
University of California-Riverside, Riverside, CA
Abstract
/
Soil contamination by heavy metals is prevalent at hazardous waste sites in the United States. To remediate
these sites, there is a strong interest in developing novel polymeric materials that have superior affinity and
selectivity because of their unique physical, chemical, and biological properties. Genetic and protein engineer-
ing have emerged as the latest tools for the construction of novel materials that can be controlled precisely at
the molecular level. Previously, an elastin-like polypeptide (ELP) composed of a polyhistidine tail (ELPH12)
has been shown to have promising cadmium removal capability. ELP undergoes a reversible thermal precipita-
tion within a wide range of temperatures, enabling easy recovery of the sequestered cadmium. The goal of this
research project is to further investigate the feasibility of utilizing ELP biopolymers for both ex situ and in situ
soil cadmium remediation application. Different metal-binding domains will be incorporated to investigate the
efficiency of cadmium removal from contaminated soil.
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Synthesis, Characterization, and Catalytic Studies of Transition Metal
Carbide Nanoparticles as Environmental Nanocatalysts
S.IsmatShah
University of Delaware, Newark, DE
Abstract
This research project deals with exploring the possibility of using alternative catalytic materials, transition
metal carbides (TMC) and oxycarbides (defined as oxygen-modified carbides), to replace platinum (Pt)-group
metals for the reduction of NOX. The carbides and oxycarbides of Groups 4-6 early transition metals are char-
acterized by many unique and intriguing catalytic properties. The catalytic properties of TMC and transition
metal oxycarbides (TMOC) have been the subject of many investigations in the fields of catalysis and surface
science. From the catalysis literature, it is now well established that the catalytic properties of TMC and
TMOC often show strong similarities to those of the more expensive Pt-group metals (Ru, Rh, Ir, Pd, and Pt).
In the past few years, several surface science groups have performed fundamental investigations of the cata-
lytic properties of TMC and TMOC. For example, the researchers have performed extensive studies aimed at
directly comparing the chemical reactivity of carbide surfaces with that of Pt-group metals. The results pro-
vided conclusive evidence that the decomposition of a variety of hydrocarbon molecules on TMC occurs via
reaction mechanisms that are characteristic of Pt, Rh, and Pd. Furthermore, comparative studies have been per-
formed on the decomposition of NO on the bulk surfaces of molybdenum (Mo) and tungsten (W) carbides and
oxycarbides. Preliminary results clearly demonstrate that carbides and oxycarbides of Mo and W are very effi-
cient in the conversion of the toxic NO pollutants into the harmless N2 molecules, with catalytic activity and
selectivity being similar or better than those of the expensive Pt-group metals.
Decomposition of NO on Carbide Modified W(lll) Surface. It is relatively easier to study the decomposition
pathways of NO on carbide modified single crystal W surfaces. This study will be extended to include the WC
and WOC nanoparticles. The decomposition pathways are investigated using a combination of temperature
programmed desorption, auger electron spectroscopy, high-resolution electron energy loss spectroscopy, and
soft x-ray photoelectron spectroscopy. All of these surfaces exhibit high activity toward the decomposition of
NO, and the only N-containing products are N2 and N2O. Furthermore, all three surfaces preferentially produce
Na overN2O from the decomposition of NO. Oxygen atoms, produced from the decomposition of NO, react
with carbide surfaces to produce gas-phase CO at high temperatures. In addition, the results demonstrate that
cycles of alternate NO/hydrocarbon treatments can regenerate the carbide overlayer on W(l 11), and the regen-
erated C/W(111) surface remains active in the decomposition of NO.
EXAFS Study of the Nanoparticles. Extended X-ray Absorption Fine Structure (EXAFS) analysis shows the
nearest neighbor coordination in materials. These studies are important because WC surfaces have catalytic
behavior for NO decomposition similar to that of Pt. If the same electronic structure and local chemistry in the
WC nanoparticles are observed as in the bulk surfaces, their catalytic properties can be correlated. Previously,
it was reported that the synthesis process can be modified to obtain desired surfaces. EXAFS is used to com-
pare the local chemistry of the nanoparticles with that of bulk surfaces. Figure la shows the comparison of the
W K-edge oscillation for the nanoparticle film, with spectra from the bulk and theory (FEFF). Figure Ib shows
the edge oscillations of the nanoparticles and the bulk only. The similarity on the structure is readily observ-
able, indicating that the local chemistry of the nanoparticles is similar to that of the bulk; therefore, catalytic
properties of the nanoparticles should be similar to that of the bulk.
NOf Decomposition With WCX Nanoparticles. Preliminary experiments to study NOX decomposition with WCX
nanoparticles were conducted in an in-line reactor. The reactor setup is shown in Figure 2. The temperature of
the reactor can be controlled from RT to 1,000 °C. Currently, only the nitrogen column in the gas chromato-
graph (GC) is being used. This will be expanded to include the NO column very shortly. A mixture of 1 per-
cent NO with He is used as the test gas. Flow rates are adjusted by using mass flow controllers. A base line for
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the experiment is obtained by passing the gas mixture through the reactor, without any catalyst. The base line
is shown in Figure 2. With the addition of the catalyst, the direct decomposition of NOX occurs according to
the reaction: NOX -> N2
The N2 signal is detected by GC. Figure 2 shows the increase in the N2 signal intensity as a function of the re-
actor temperature. The decomposition reaction starts to occur at temperatures above 200 °C, increases rapidly
up to about 500 °C, and becomes constant beyond 500 °C. We think that the leveling off is a result of the loss
of some carbon form of the nanocatalyst. The next set of experiments includes the addition of hydrocarbon to
the feed gas. This will not only imitate the automobile exhaust better, it also will stabilize the carbon concen-
tration in the nanoparticles and enhance the activity further with the temperature.
Figure 1. EXAF results comparing the nanoparticles, bulk and
theoretical spectra.
, With WC, NinoplrtklM
Ba»e Line_No Cat
490 300 BOO TOO
T«ftlp>rltur« ^ Cfltobt)
Figure 2. NOX decomposition with and without the catalyst.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
A Novel Approach To Prevent Biocide Leaching
Patricia Heiden', Laurent Matuana2, and Ben Dawson-Andoh3
'Michigan Technological University, Houghton, MI; ^Michigan State University,
East Lansing, MI; 3West Virginia University, Morgantown, WV
Abstract
Newer wood preservatives are formulated without chromium and arsenic so that negative environmental im-
pact is reduced. However, the removal of chromium from biocide formulations also leaves them more suscep-
tible to leach, which can negatively affect ecosystems, particularly wetlands. Loss of biocide also can reduce
the useful lifetime of preserved wood products. Therefore, from both an economic and environmental stand-
point, it is highly desirable to prevent biocide leach. The objective of this research project is to use nanotech-
nology as a means to deliver and "fix" copper and organic biocides into wood to eliminate or reduce biocide
leaching. Nanotechnology, which is routinely applied to deliver and control the release of Pharmaceuticals, has
been too costly to use in many other areas, but new technologies and new commercial uses for nanotechnology
are making this technology more efficient and less expensive. Given that the awareness of ecological and eco-
nomic consequences of biocide leach has increased and nanotechnology is becoming more economical to use,
this project is investigating the ability of nanotechnology to reduce biocide loss. Specifically, the researchers
are seeking to develop a practical approach to incorporate wood preservatives into polymeric nanoparticles that
can be introduced into wood with the effect of controlling the biocide release rate to reduce or eliminate loss to
leach.
The U.S. Environmental Protection Agency determined that in 2000, the U.S. wood preservatives market was
809,000,000 pounds.1 In 2003, the wood preservatives industry stopped using chromated copper arsenate
(CCA), which has resulted in significant changes in the U.S. wood preservatives market. Although in 2005 this
market was $500 to $600 million2, the nature of these wood preservatives is changing. Although use of some
types of wood products is declining, the total demand and market value for treated wood products is increas-
ing. Discontinuing the use of CCA may have removed one ecological issue associated with wood preservative
use, but at the same time it may have aggravated another, biocide leach. Newer wood preservative formula-
tions do not "fix" to wood. Although low solubility biocides are often favored because of leaching, this is an
inadequate response. Even low solubility biocides will leach, resulting in negative economic and environ-
mental consequences.
Loss of wood preservatives to leaching not only leaves the wood product vulnerable to biological attack, which
reduces its useful lifetime, but also the leached biocide has negative consequences to sensitive environments,
especially wetlands and other moist environments where leaching is more rapid. If leaching can be reduced or
eliminated, wetlands will be less at risk and demands need not be made on forest ecosystems to replace wood
products that degraded prematurely because biocide was lost to leach.
This research project will prepare biocide-containing core-shell nanoparticles using a hydrophilic shell to allow
the particle to be stable in water, and a hydrophobic core containing the biocides, as shown in Figure 1.
Figure 1. Core-shell nanoparticle having a biocide reservoir surrounded by a polymer shell
to facilitate conventional pressure-treatment of wood.
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The key synthetic targets of the project are identifying the best methods to prepare core-shell nanoparticles
with high biocide loading, good particle stability in water, and high delivery efficiency into wood. The major
hypotheses to be tested are: (1) a core-shell nanoparticle structure can be used to produce a stable aqueous
suspension of biocide-containing nanoparticles; (2) a suitable release rate of organic and inorganic biocides
can be attained using a core-shell nanoparticle structure that can control the biocide release rate to increase the
biological efficacy of the biocide and therefore increase the protected lifetime of treated wood; (3) wood pres-
ervation can be achieved using less biocide than currently required using today's technology; and (4) encapsu-
lation of biocides within diffusion-controlled nanoparticles can reduce or eliminate biocide leaching.
Incorporating biocides into polymeric nanoparticles allows the bulk of the biocide to be safely stored within
the nanoparticle's interior, where it is protected from leach and random degradative processes. The polymeric
nanoparticle therefore functions initially as a biocide delivery medium, then as a protective reservoir, and fi-
nally as a controlled release device. The release mechanism is predominantly diffusion controlled, with the
rate of diffusion depending on the moisture around the nanoparticle and the hydrophobicity of the polymer.3'4
By using a solid polymer as a biocide carrier, even water-insoluble biocides can be delivered into wood with-
out a surfactant, which by itself reduces leaching. By controlling the hydrophobicity of the polymer, the release
rate of the biocide can be kept low, ideally sufficiently low so that only the minimum amount of biocide
needed to preserve the wood is ever outside the nanoparticle at a given time. By avoiding the use of surfactants
and maintaining a diffusion rate of biocide out of the nanoparticle that is sufficient only to maintain biological
efficacy, the risk of biocide leach is significantly reduced, thereby gives the effect of biocide fixation.
The expected benefits to be gained by incorporating biocides within a polymeric nanoparticle reservoir include.
all of the beneficial effects of preventing contamination of ecosystems through leaching, extending the service
life of wood and wood products, and effective protection of wood products using lower levels of biocide.
References:
1. U.S. EPA. 2000-2001 Pesticide market estimates: usage, http://www.epa.gov/oppbeadl/pestsales/
Olpestsales/usage2001 .html.
2. The outlook for the U.S. treated wood and wood preservatives market, 2006-2016. Little Falls, NJ: Kline
and Company Inc. (http://www.klinegroup.com/brochures/Y603/brochure.pdf).
3, Liu Y, Laks P, Heiden P. Controlled release of biocides in solid wood. Part 3. Preparation and Characteri-
zation of Surfactant-Free Nanoparticles. Journal of Applied Polymer Science 2002;86:615-621.
4. Liu Y, Laks P, Heiden P. Wood preservation using nanoparticles for the controlled release of fungicides:
soil jar studies using G. Trabeum and T. Versicolorviood decay fungi. Holzforschung 2003;57:135-139.
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A Novel Approach To Prevent Biocide Leaching
Patricia Heiden1, Laurent Matuana2, and Ben Dawson-Andoh3
Michigan Technological University, Houghton, MI;2Michigan State University,
East Lansing, MI; 3West Virginia University, Morgantown, WV
Environmental Applications/Implications
The EPA has determined that in 2000 the U.S. wood preservatives market was 809,000,000 pounds.1 Although
use of some types of wood products is declining, the total demand and market value for treated wood products
is increasing. In 2003, the wood preservatives industry stopped using chromated copper arsenate (CCA), which
has resulted in significant changes in the U.S. wood preservatives market. Although in 2005 this market was
$500-600 million, Kline and Company, Inc. (Little Falls, New Jersey) observed that the nature of these wood
preservatives is changing.2 Discontinuing use of CCA may have removed one ecological issue associated with
wood preservative use, but it may have aggravated another, biocide leach. Newer wood preservative formula-
tions do not "fix" to wood, which can facilitate leach. Although low solubility biocides are often favored for
the purpose of reducing leach, this is an inadequate response. Even low solubility biocides will leach, espe-
cially in moist environments, resulting in negative economic and environmental consequences.
Loss of wood preservatives to leaching has detrimental consequences to the preserved wood and to the envi-
ronment in which the wood is used. Loss of biocide leaves the wood product vulnerable to biological attack,
reducing its useful lifetime, and requiring premature replacement of wood products. This places additional de-
mands on forests and is costly. The leached biocide has negative consequences to the local environments, es-
pecially wetlands and other moist environments, where leaching is more rapid. If leaching can be reduced or
eliminated, wetlands will be less at risk, and the extended longevity of wood products will benefit forest eco-
systems. Economic benefits are expected to include a longer useful lifetime for wood products even though
less biocide might be required. Incorporating biocides into polymeric nanoparticles allows the bulk of the bio-
cide to be safely stored within the nanoparticle's interior, where it is protected from loss to leach and random
degradative processes. The polymeric nanoparticle functions first as a protective reservoir but also serves as a
controlled release device, where the biocide is released by a predominantly diffusion controlled process. The
rate of diffusion is controlled by controlling the hydrophobicity of the polymer carrier.3'4
Using a solid polymer as a biocide carrier allows even water-insoluble biocides to be delivered into wood
without a surfactant, which by itself reduces leaching. By controlling the hydrophobicity of the polymer, the
release rate of the biocide can be kept low, and ideally reduced to the rate needed so that the biocide concentra-
tion outside the nanoparticle is maintained at the minimum level needed to preserve the wood, while the unre-
leased biocide is maintained within the nanoparticle reservoir. By avoiding the use of surfactants and maintain-
ing a low diffusion rate of biocide to a level to maintain biological efficacy, the loss of biocide to leach can be
minimized, and the effect of fixation can be mimicked.
The expected benefits to be gained by incorporating biocides within a polymeric nanoparticle reservoir include
all the beneficial effects of preventing contamination of ecosystems through leaching, extending the service
life of wood and wood products, and the ability to effectively protect wood products at lower levels of biocide
use.
References:
1. U.S. EPA. 2000-2001 Pesticide market estimates: usage, http://www.epa.gov/oppbeadl/pestsales/01pest-
sales/usage2001.html.
2. The outlook for the U.S. treated wood and wood preservatives market, 2006-2016. Little Falls, NJ: Kline
and Company, Inc. Available online at http://www.klinegroup.com/brochures/Y603/brochure.pdf.
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3. Liu Y, Laks P, Heiden P. Controlled release of biocides in solid wood. Part 3. Preparation and Charac-
terization of Surfactant-Free Nanoparticles. Journal of Applied Polymeric Sciences 2002;86:615-621.
4. Liu Y, Laks P, Heiden P. Wood preservation using nanoparticles for the controlled release of fungicides:
soil jar studies using G. Trabeum and T. Versicolor wood decay fungi. Holzforschung 2003;57:135-139.
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Section?. Fate/Transport
As nanotechnology progresses from research and development to commercialization and use, manufactured
nanomaterials may be released into the environment. EPA is interested in determining the routes through
which manufactured nanomaterials enter the environment and their modes of dispersion, interaction, and
degradation within the environment: soil, water, atmosphere, and biosphere. Persistence and bioaccumulation/
• biomagnification are factors that offer guidance for determining whether substances are classified as hazar-
dous. Although the short-term effects of a toxic nanomaterial may result from a single exposure, the long-term
effects due to bioaccumulation and persistency may be more severe, ranging from lasting health problems to
organ damage. Biomagnification, a side effect of bioaccumulation, is the amplification of the concentrations of
nanomaterials in each successive step in the food chain. Keeping in mind the novel properties of nano-
materials, new or modified test methods, basic datasets for environmental fate/transport endpoints, and
applications of new or existing air dispersion, soil transport, groundwater models may be needed.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Chemical and Biological Behavior of Carbon Nanotubes
in Estuarine Sedimentary Systems
7*. Lee Ferguson
University of South Carolina, Columbia, SC
Abstract
The general objectives of the proposed research are to: (1) determine factors controlling the fate of single-
walled carbon nanotubes (SWNTs) and their synthetic by-products in estuarine seawater, sediment, and sedi-
ment-ingesting organisms; (2) examine the impact of SWNTs and by-products on the disposition of model or-
ganic contaminants in estuarine sediments; (3) determine whether the presence of SWNTs and by-products in
estuarine sediments affects the bioavailability of model organic contaminants to estuarine invertebrates; and
(4) assess the toxicity of SWNTs and by-products to suspension- and deposit-feeding estuarine invertebrate
models in seawater suspension alone, and/or in combination with estuarine sediments.
This research project will address these objectives through a series of experiments designed to provide a holis-
tic picture of the behavior of SWNTs and their synthetic by-products on entry into the estuarine environment.
These experiments will include tracing the fate and phase-association of 14C-SWNTs and by-products under
simulated estuarine conditions and through ingestion by deposit-feeding organisms, batch sorption studies to
examine the affinity of SWNTs for model hydrophobic organic contaminants (HOC) in the estuarine environ-
ment, laboratory-scale bioaccumulation experiments designed to test modulation of HOC bioavailability by co-
occurring SWNTs in estuarine sediments, and dose-response experiments designed to test the potential for
SWNTs and by-products to directly cause adverse effects on a sensitive estuarine infaunal invertebrate (the
harpacticoid copepod, Amphisascus tenuiremus).
The proposed work will, for the first time, address the physical, chemical, and biological behavior of novel and
emerging carbon nanotube materials under environmental conditions typical of estuaries. In total, this study
will address not only the potential for SWNTs to be transported, accumulate, and cause direct deleterious ef-
fects within estuarine environments, but also the potential for linked effects on the biological and chemical
behaviors of known priority pollutants common in estuarine sediments. This combined approach represents a
nove! way of addressing the environmental impact of an emerging synthetic nanomateriai and will thus provide
the U.S. Environmental Protection Agency and the scientific community with an entirely new and highly rele-
vant dataset for risk assessment of SWNT-derived contaminant discharge. Further, the work will generate new
scientific knowledge related to the behavior of these highly novel nanomaterials under conditions not normally
tested in the course of nanoscience research (e.g., nonmammalian biological systems, highly saline aqueous
solutions, and complex sediment media). This knowledge may become useful in designing new nanoscale
technologies in, for example, environmental engineering or "green" manufacturing techniques.
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A Focus on Nanoparticulate Aerosol and Atmospherically
Processed Nanoparticulate Aerosol
Vicki H. Grassian
University of Iowa, Iowa City, IA
Abstract
The goal of the current research is to determine the potential effects of manufactured nanoparticles on human
health if they were to become entrained in the atmosphere. Because a number of physical and chemical proper-
ties are size-dependent on nanometer length scales, it is important to fully characterize nanomaterials in any
studies related to the environmental and health impacts of these materials. The approach to this study is to
characterize a variety of manufactured nanomaterials using a wide range of techniques and methods, including
surface spectroscopy and surface reactivity so that both bulk and surfaces properties are well understood on a
molecular level. These well-characterized particles are then used in inhalation exposure studies. Additional
characterization of the particles are done once the aerosol has been generated to determine if the particles ag-
gregate or retain the size distribution determined prior to aerosol generation. Toxicology assessments of the
animals exposed to these well-characterized nanoparticulate aerosols include murine acute pulmonary inflam-
mation assay, murine sub-acute pulmonary toxicology evaluation, and murine microbial challenge host resis-
tance evaluation to screen for acute and sub-chronic pulmonary effects. The studies thus far have focused on
some of the smallest available commercial nanoparticles, 5 nm TiOa. A series of acute and sub-chronic expo-
sures have been completed.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Transformations of Biologically Conjugated CdSe
Quantum Dots Released Into Water and Biofilms
Patricia A. Holden1 and Jay L, Nadeau2
'University of California-Santa Barbara, Santa Barbara, CA;
2McGill University, Montreal, Quebec, Canada
Abstract
Regarding CdSe quantum dots (QDs) in soil and water, where bacterial interactions will occur, this project is
addressing the following questions:
• What are the biotic fates of CdSe QDs?
• What are the effects of QDs on bacteria?
• How do fates and effects depend on: QD conjugation? QD size? Environmental factors (e.g., light, pH,
reduction potential, oxygenation)? Bacterial strain? Growth habit (biofilm or planktonic)?
Thus tar, the results have facilitated a working conceptual model of strain-dependent QD interactions with bac-
teria:
• External nonspecific labeling where unconjugated QDs cannot passively diffuse into cells.1"2
• Specific binding and nonspecific uptake2 where conjugates are recognized by receptors on the cell enve-
lope, and light-mediated membrane damage from oxygen free radicals facilitates transmembrane transport;
thus allowing conjugated QDs less than 5 nm diameter to enter cells.
• External breakdown and transmembrane diffusion of constituent metals, where Cd2+ may be expelled; Se2'
may be expelled or oxidized to Se° and then retained or expelled; or Cd2+ and Se2" may combine into
nanoparticles and be expelled or retained.
Specific results in support of this working model were generated from studies involving several bacterial
strains. In Bacillus sub tills, conjugated QDs produced in the dark but incubated in visible light with bacteria
results in the brightest bacterial labeling and the least amount of blue shift. This result supports the concept
that CdSe QDs, when exposed to light in water, produce oxygen free radicals that impart membrane damage,
allowing conjugated QDs to enter cells.2 However, tight-induced membrane damage, as shown by transmission
electron microscopy (TEM), appears to be transient because after a short time most cells are indicated in epif-
luorescence microscopy by a stain specific for viability. In Escherichia colt, conjugated QDs are taken in by
similar mechanisms, but are then expelled after 1 hour.
Genotoxicity apparently occurs in B. subtilis, as evidenced by cellular elongation or the absence of cell divi-
sion. Elongated cells are observed to contain CdSe rich occlusions, and several nuclear regions.
Toxicity of constituent metals is observed in Pseudomonas spp. liquid culture, whereby rapid growth occurs
with selenite and slower growth occurs with Cd2+, whether alone or with selenite. In that growth with CdSe,
QDs are somewhere between growth without Cd2* and with Cd2+; it is likely that some QDs are breaking down
and causing toxicity, while some are intact outside the cells. Under aerobic conditions, reduction of selenite to
selenide and elemental selenium is occurring, and this may occur intracellularly as well.
Toxicity of Cd2+ to planktonic Pseudomonas is exacerbated by 200 mg/L selenite, and the production of fluo-
rescence for this condition suggests that nanoparticles might be forming intracellularly, or at least very near the
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
cells. In any case, whether QDs are entering the cell whole or breaking down and then entering, the co-
occurrence of Cd2* and large amounts of Se2", which is facilitated by the presence of QDs, appears to be more
toxic than either metal alone.
When cultivated as unsaturated biofilms, the total yield of DNA in Pseudomonas is not affected by equimolar
amounts of metals either in the form of QDs or as constituent metals. Cadmium uptake is greater for the con-
stituent metal than for QDs. Lastly, cadmium appears to enhance intracellular accumulation of selenium, which
may imply intracellular reduction of selenite followed by Cd2+ binding inside the cell.
In conclusion, work to date includes: (1) a putative, conceptual model for how QDs interact with bacteria; (2)
evidence to support several interaction mechanisms, including light-activated QD production of membrane-
damaging free radicals, free radical-assisted transmembrane transport of conjugated QDs, and conjugated QD-
mediated DNA damage, arresting cellular division; and (3) early evidence for intracellular QD assembly in
biofilms (Cd-enhanced intracellular sequestration of Se) and in planktonic culture (fluorescence and exacerba-
tion of Cd2+ toxicity when high amounts of selenite are present).
References:
1. Kloepfer JA, Mielke RE, Wong MS, Nealson KH, Stucky G, Nadeau JL. Quantum dots as strain- and me-
tabolism-specific microbiological labels. Applied and Environmental Microbiology 2003;69:4205-4213.
2. Kloepfer JA, Mielke RE, Nadeau JL. Uptake of CdSe and CdSe/ZnS quantum dots into bacteria via purine
dependent mechanisms. Applied and Environmental Microbiology 2005;71:2548-2557.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Absorption and Release of Contaminants
Onto Engineered Nanoparticles
Mason Tomson
Rice University, Houston, TX
Abstract
Little is known about the environmental fate of manufactured nanomaterials. Sorption is often the most impor-
tant fate mechanism for environmental contaminants. This research project will test four hypotheses: (1) car-
bon nanostructu'res have a high capacity for sorption/desorption hysteresis with polynuclear aromatic hydro-
carbons and other common organic contaminants; (2) the sorption capacity of inorganic nanomaterials for
heavy metals is the same as the corresponding bulk crystals, when corrected for surface area; (3) sorption of
naturally occurring humic materials and surfactants to metal oxide and carbon nanomaterials will diminish the
sorption capacity of heavy metals on oxides and increase the sorption of hydrocarbons on carbon nanomateri-
als; and (4) the transport of nanoparticles in soils, sediments, and porous media will be vastly greater than the
corresponding colloids or bulk materials. In the first year of this project, the sorption/desorption behavior of
both organic and inorganic contaminants to nanomaterials and the fate and transport of naphthalene (an organic
contaminant) and colloidal C60 particles in soil column have been successfully characterized. The researchers
have attended several national conferences and published 12 peer-reviewed papers (or accepted for publica-
tion) in the last year and submitted one U.S. patent application.
Environmental Fate of Carbon Nanomaterials
Many soils or sediments contain various forms of carbonaceous materials such as coals, kerogens, and black
carbons, which have been reported to have high affinity for hydrophobic organic contaminants. C60 might
have similarly important environmental impact as to other forms of carbon (e.g., black carbons). Although C60
is virtually insoluble in water, nano-C60 particles (a term used to refer to underivatized C60 crystalline
nanoparticles, stable in water for months, mean diameter -100 nm in this study) can be formed in water simply
by stirring, or by dissolving C60 in nonpolar solvents, mixing into water, followed by the removal of the sol-
vents. In this study, the adsorption and desorption of naphthalene and 1,2-dichlorobenzene with aqueous nano-
C60 particles prepared by both methods was investigated. To compare the adsorptive property of C60 with
other carbons (e.g., naturally occurring organic carbon in soils) and activated carbon, adsorption and desorp-
tion of naphthalene with Anocostia River sediment (foe - 3.7%) and activated carbon particles (commercial,
and nano-activated carbon particles prepared in the laboratory) were conducted and compared with that of
C60.
Results show that adsorption to nano-C60 particles is similar to that of nano-activated carbon particles, and is
stronger that that of soil organic carbon. Desorption hysteresis was observed for naphthalene desorption from
all three forms of carbon tested: C60, activated carbon, and soil organic carbon. A two-compartment sorption
model was used to describe naphthalene adsorption and desorption with these three forms of carbon, where
there are solid-water distribution coefficients for the first and the second compartment; (/Yg/g) is defined as a
maximum sorption capacity for the second compartment; and the factor f (0 ,,T f ,,T 1) denotes the fraction of
the second compartment that is filled at the time of exposure. Data of naphthalene adsorption and desorption
with C60, activated carbon, and soil organic carbon were fitted with this two-compartment model very well,
indicating that there may be a common pattern for the adsorption and desorption of naphthalene with these
three forms of carbon. Therefore, it may be possible to predict the properties of nano-carbons, such as C60,
from that of other carbon forms. This finding may have important environmental significance.
It has been reported that nano-C60 particles are toxic to fish cells and cultured human cells; thus, people may
be more concerned about the potential exposure to C60 if it is mobile in water. One might expect that C60
would not enter groundwater in great quantities due to the insolubility of C60 in water. Water-stable nano-C60
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
particles, however, can be formed in water by several simple methods, as discussed above, indicating that C60
might be mobile in groundwater. Dissolved organic matter in groundwater has been reported to significantly
enhance the partition of neutral organic contaminants into water and thus enhance the transport of those con-
taminants. It is unknown whether the release of C60 and other nano-sized carbonaceous nanomaterials into
aqueous environments will have the similar effect. Therefore, it is of central importance to investigate the C60
transport in water/sediment, and its effect on contaminant transport.
In this work, the transport of nano-C60 particles through a sandy soil column (foe = 0.0027%) was investi-
gated for the first time. Nano-C60 particles showed limited mobility at typical groundwater Darcy velocity. At
the Darcy velocity of 3 ft/d, the maximum nano-C60 particles breakthrough was only 47 percent, and an unex-
pectedly high deposition of nano-C60 to the soil column was observed shortly after the peak value, probably
indicating an irreversible sorption of nano-C60 particles on the soil column. It might be because the accumula-
tion of nano-C60 on the collector surface served as favorable sites for subsequent nano-C60 deposition. Nano-
C60 particles were more mobile in the soil column at higher flow velocities (e.g., 30 and 90 ft/d). A model
developed for the transport of colloids in porous media by K.M. Yao, et al., and C.R. O'Melia, et al., was used
to describe nano-C60 particles transport in the soil column. The theoretical single collector efficiency, the par-
ticle attachment efficiency, and the maximum particle travel distance were calculated for nano-C60 particles
transport at different flow velocities. Experimental results showed that at the flow velocity of 30 ft/d, nano-
C60 particles could travel 68 cm through the soil column before 99.9 percent of the particles were immobi-
lized; while at the flow velocity of 90 ft/d, nano-C60 particles could travel 1.32 m through the soil column be-
fore 99.9 percent of the particles were immobilized. Spiked release of nano-C60 particles was observed repeat-
edly on flow resumption following a few days of flow shut-in. Spiked release of nano-C60 particles also was
observed during the change of flow velocities. This observed phenomenon may have broad environmental sig-
nificance.
The transport of naphthalene through the same soil column with 0.18 percent of nano-C60 particles deposited
was measured. The observed retardation factor for the naphthalene breakthrough curve with the Lula/0.18 per-
cent-nano-C60 column was about 13, indicating that nano-C60 particles deposited in the soil column adsorbed
naphthalene similarly to soil organic carbon.
Adsorption and Desorption of Heavy Metal and Arsenic to Metal Oxide Nanoparticles
The objectives of the current study were to investigate the effect of particle size on adsorption and desorption
of typical environmental pollutants (i.e., arsenic and cadmium) onto metal oxide bulk crystals versus nanopar-
ticles (anatase and magnetite), and to examine the competitive sorption between naturally occurring humic
materials and heavy metals. In collaboration with Dr. Colvin's group through the support of the Center for
Biological and Environmental Nanotechnology (CBEN) at Rice University, several laboratory-synthesized
magnetites were studied. On a surface-area basis, cadmium adsorptions to different sized anatase nanocrystals
are similar. The maximum adsorption densities for arsenic to magnetite are also simitar for commercially pre-
pared large magnetite crystals (300 nm) and magnetite nanoparticles (20 nm). Surprisingly, the adsorption ca-
pacity for arsenic to laboratory-synthesized magnetite (11.72 nm) is significantly higher than the commercially
available bulk and nanocrystals. Laboratory-synthesized magnetite nanoparticles can remove approximately
100 times more arsenic than larger commercial materials. With respect to desorption, the cadmium desorption
from both particle sizes appeared to be completely reversible; however, arsenic was not readily released from
magnetite nanoparticles, presumably because the binding of the adsorbed arsenic results in the formation of
highly stable iron-arsenic complexes. The presence of natural organic matter (NOM) decreased adsorption of
both arsenic species to magnetite nanoparticles. NOM in the solution probably competes with arsenite and ar-
senate for surface sites on magnetite nanoparticles. With joint support from CBEN, these results are currently
applied to test the efficiency of magnetite nanoparticles in removing arsenic from drinking water. A U.S. pat-
ent application has been submitted.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Fate and Transport of C60 Nanoparticles
in Unsaturated and Saturated Soils
Kurt D. Pennell
Georgia Institute of Technology, Atlanta, CA
Abstract
Widespread production and application of manufactured nanomaterials is expected to increase dramatically
over the next decade, which will inevitably lead to the release of carbon-based nanoparticles into the environ-
ment. Our current understanding of nanomaterial fate and transport in subsurface systems is extremely limited.
For example, it is not known how nanomaterials will interact with soil matrices, whether or not nanoparticle
transport can be accurately modeled using classical filtration theory, and how unsaturated soil conditions will
impact nanomaterial transport and retention. The overall goal of this research project is to expand our knowl-
edge of carbon (C-60) nanomaterial fate and transport in natural soils. The three specific objectives of this pro-
ject are to: (1) investigate the fate and transport of C-60 nanomaterials in water-saturated soils as a function of
soil properties and systems parameters; (2) assess the effects of C-60 nanomaterials on soil water retention,
water flow, and transport in unsaturated soils; and (3) develop and evaluate a numerical simulator to describe
C-60 nanomaterial transport, retention, and release in subsurface systems.
This research project will focus on two relative welt-characterized, commercially available carbon nano-
materials: C-60 fullerene, which is very insoluble in water but forms nanoscale aggregates (20-150 nm diame-
ter) that are stable in solution, and fullerol, a relatively water-soluble fullerene derivative that exists as
nanoparticles (1-2 nm diameter) in solution. Detailed laboratory experiments will be conducted to explore the
fate and transport of these nanomaterials in natural soils. Experimental variables to be considered include soil
organic carbon content, grain size, and water content. Fate and transport experiments will be performed in one-
and two-dimensional flow systems, under both water-saturated and unsaturated conditions. Experimental re-
sults will be used to evaluate conceptual models of nanomateria! retention and release in porous media, and
will be directly coupled to the development and validation of a numerical simulator for prediction of nanoma-
terial fate and transport in subsurface systems.
The research is expected to greatly improve the fundamental knowledge of engineered nanomaterial transport,
retention, and release in natural porous media. The coupling of detailed experimental research and mathemati-
cal modeling will provide for rigorous testing of conceptual models of nanomaterial behavior in subsurface
systems, and will culminate in the development of a numerical simulator capable of predicting nanomaterial
fate and transport over a range of conditions that might be encountered in natural systems. It is further antici-
pated that the experimental methods, mathematical models, and numerical simulator can be adapted or directly
used to predict the fate and transport of other nanomaterials, such as ferroxane and single-wall carbon nano-
tubes, in subsurface systems.
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Cross-Media Transport, Transformation, and Fate
of Carbonaceous Nanomaterials
Linsey C. Man
Virginia Tech, Blacksburg, VA
Abstract
Research that accounts for cross-media effects is needed to understand the environmental fate of manufactured
nanomaterials. All known studies of manufactured nanomaterials in aquatic systems have used the pure, or
"fresh," form of the compounds. However, nanoparticles that are released into the atmosphere undergo trans-
formations (coagulation, coating, and reactions) that will change the particles' size, chemical composition, and
surface properties. When these "aged" particles later deposit onto the earth's surface, they may have very dif-
ferent fates in the aquatic and terrestrial environments compared to the "fresh" compounds.
The overall objective of this research is to conduct a cross-media assessment of the transport, transformation,
and fate of manufactured nanomaterials in atmospheric, aquatic, and terrestrial environments. A key com-
ponent of the project is to examine how "fresh" versus atmosphericaliy "aged" nanomaterials behave in aquatic
and terrestrial systems. The experiments focus on carbonaceous nanomaterials (CNMs, including fullerenes
and endohedral metallofullerenes).
In the first set of experiments, the rates at which airborne CNMs transform under naturally occurring condi-
tions will be determined. In the second set of experiments, the interactions of both "fresh" and atmospherically
"aged" CNMs with water and soil will be examined to evaluate their environmental transport and reactivity.
Specific tasks are to: (1) quantify the rate of reaction of airborne CNMs with ozone; (2) age CNMs in a smog
chamber and characterize the processed aerosol; (3) evaluate transport of "fresh" and atmospherically "aged"
CNMs in porous media; (4) develop CNM-functionaJized atomic force microscope tips; and (5) characterize
CNM interactions with soil surfaces in aquatic systems.
The cross-media approach will lead to significant gains in the understanding of how manufactured CNMs are
transported and transformed in the environment. The research will determine how CNMs transform in the at-
mosphere under naturally occurring conditions and to what extent such transformations affect their transport in
aqueous systems. This study will be the first to utilize atomic force microscopy to quantify the adhesive and
repulsive forces that exist between CNMs (both "fresh" and "aged") and relevant environmental surfaces. An
improved understanding of the environmental effects of manufactured CNMs will help address barriers to
adoption of nanotechnology.
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Section 8. Toxicity
As nanotechnology progresses from research and development to commercialization and use, it is likely that
manufactured nanomaterials and nanoproducts will be released into the environment. EPA is charged with
protecting human health and the environment, as well as ensuring that the application of engineered nano-
technology products occur without unreasonable harm to human health or the environment. The unique
features of manufactured nanomaterials and a lack of experience with these materials hinder the risk evaluation
that is needed to inform decisions about pollution prevention, environmental clean-up and other control
measures, including regulation. Beyond the usual concerns for most toxic materials, such as physical and
chemical properties, uptake, distribution, absorption, and interactions with organs, the immune system and the
environment, the adequacy of current toxicity tests for chemicals needs to be assessed to develop an effective
approach for evaluating the toxicity of nanomaterials. To the extent that nanoparticles are redox active or elicit
novel biological responses, these concerns need to be accounted for in toxicity testing to provide relevant
information needed for risk assessment to inform decision making.
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Short-Term Chronic Toxicity of Photocatalytic Nanoparticles
to Bacteria, Algae, and Zooplankton
Chin-Pao Huang
University of Delaware, Newark, DE
Abstract
The overall objective of this project was to assess the effect of photocatalytic nanoparticles on the toxicity of
three organisms, including bacteria, algae, and daphniad. The target organisms studied were: bacteria (Es-
chericbia coli; TK2), algae (Selenastrum capricormttum), and daphniad (Ceriodaphnia dubia). A series of
TiOj nanoparticles in different particle size fractions were manufactured using the sol gel or CMVD technique.
The TiOa particles were characterized for the particle size using both the SEM and the DLS methods before
use. Experimentally, a 28-h E, coli culture or 2-day neonates or log-phase algae culture were exposed to
photocatalytic nano-TiO2 at various concentrations (e.g., 0 to 1 g/L) and particle size (e.g., 3 to 100 nm) both
in darkness and the presence of a simulated solar light. The growth or survival rate was used to determine the
LCso value of all tested organisms. EC5o values of daphniad were determined from the reproduction rate. Re-
sults show that in the size range of 5 to 30 nm, there appeared to be no significant difference in toxic response
to the photocatalytic TiO2 particles. The presence of light irradiation significantly decreased the survival and
the reproduction (in the case of daphniad) of tested organisms due to additional photocatalytic activity. Photo-
catalytic reactions generated hydroxyl radical, which is a strong oxidation agent that can cause great stress and
damage to the cells. Cell damage was observed in terms of lipid peroxidation (e.g., production of malondialde-
hyde, MDA), cellular respiration (e.g., reduction of 2,3,5-triphenyltetrazolium chloride, TTC), and antioxidant
enzyme (e.g., glutathione-S-transferase, GST). Results indicated an increase in the generation of MDA, TTC,
and GST upon exposure of tested organisms to nano-TiOi; photocatalytic activity markedly increased the pro-
duction of MDA, TTC, and GST.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Physical and Chemical Determinants of Nanofiber/Nanotube Toxicity
Robert Hurt and Agnes Kane
Brown University, Providence, RI
Abstract
Carbon nanotubes (CNTs) and nanofibers (CNFs) are now being synthesized and processed in large quantities,
but their potential health risks have yet to be fully assessed. CNTs and CNFs are long, thin, and bio-persistent
and have properties in common with asbestos, a group of crystalline, iron-containing mineral fibers that are
known human carcinogens. One hypothesis for asbestos-related disease is that redox catalyzed generation of
reactive oxygen species causes DNA damage and cytotoxicity. The redox-active species in asbestos is iron,
which can be mobilized from the crystal lattice by natural dictators, and then redox cycles to generate free
radicals, such as superoxide anion and hydroxyl, in the presence of physiologic reductants such as ascorbate.
Hydroxyl radical is particularly aggressive, reacting at diffusion-limited rates with DNA and most other bio-
logical molecules. Iron is the single most common element used in CNT/CNF catalyst formulations and, de-
spite purification procedures, most CNT/CNF samples contain significant quantities of residual catalyst.
This study examines the potential cytotoxicity of iron-containing carbon nanomaterials using a variety of mo-
lecular and cellular endpoints, including iron mobilization, induction of plasmid DNA single-strand breaks,
and the viability and morphology of murine macrophages. The iron in catalytically grown nanotubes varies in
chemical composition (metal, oxide, carbide) and can be partially or wholly encapsulated by carbon, hindering
its interaction with species in surrounding fluid media and possibly suppressing redox activity. To manage this
complexity, experiments were first carried out on a model nanomaterial system in which the amount, form, and
accessibility of iron were carefully controlled. The mode! system chosen was non-catalytic, template-
fabricated carbon nanofibers in two forms: (1) high-purity as synthesized, and (2) surface doped with accessi-
ble iron nanoparticles. A second set of experiments were conducted on commercial multi-wall nanotubes in
four forms: (1) raw; (2) vendor purified with reduced iron content; (3) purified, then partially oxidized; and (4)
purified, then ground. The last two samples are included to test if post-synthesis handling/processing can fur-
ther expose encapsulated iron and accelerate the free radical generation process.
The doped model nanofibers showed significant Fe mobilization by ferrozine in the presence of ascorbate, a
higher frequency of DNA single-strand breaks, accompanied by macrophage activation and increased cell
death. The raw commercial nanotubes showed similar results to the Fe-doped model nanofibers indicating that
at least some of the iron is indeed redox active and not fully passivated by carbon shells. The purified nano-
tubes had much lower Fe mobilization and DNA single-strand break frequency. Partial oxidation of the puri-
fied sample restored some of the iron mobilization, suggesting that additional iron was made accessible by
oxidative tube damage. Mechanical grinding had little effect. Overall, these results suggest practical guidelines
for fabricating, purifying, and handling iron-containing carbon nanomaterials to minimize toxicity.
Success Stories
Principal Investigators (Pis) Agnes Kane and Robert Hurt gave a joint invited talk on their EPA-sponsored
research at NanoDays 2005 in October 2005, which was hosted by Rice University's Center for Biological and
Environmental Nanotechnology. Roger Hurt received an invitation to give a plenary lecture at the International
Symposium on Eco-Materials Processing and Design in Kyushu, Japan, in January 2007. Agnes Kane gave a
keynote lecture at Carbon2004 on fiber and nanofiber toxicity. Agnes Kane and Robert Hurt are serving as
editors of an upcoming special edition of the scientific journal, Carbon, devoted to the Toxicology of Carbon
Nanomaterials.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
The Fate, Transport, Transformation, and Toxicity of Manufactured
Responses of Lung Cells to Metals
in Manufactured Nanoparticles
John M. Veranth, Christopher A. Reilly, andGaroldS. Yost
University of Utah, Salt Lake City, UT
Abstract
This research project is based on the hypothesis that transition metals in particles induce pro-inflammatory
signaling and cell damage through the production of reactive oxygen species. Established cell culture models
and toxicology assays are being applied to the analysis of manufactured nanomaterials. Based on the literature
and the researcher's data, the researchers expect that the small physical size and high surface area of nanopar-
ticles (d < 30 nm) will increase cellular uptake and increase induction of pro-inflammatory signaling as com-
pared to larger particles with the same elemental composition. In vitro studies with human and rat lung cells
are being used to evaluate the effects of manufactured nanoparticles. The emphasis is on lower-cost nanomate-
rials that are sold in powder or liquid suspension form because these materials are expected to be produced and
ultimately released in the largest amount.
Currently, this study is in its first phase, using low-cost assays to screen a wide range of samples with suffi-
cient replicates for statistical power. This phase (Figure 1) emphasizes measurement of cytotoxicity, induction
of the proinflammatory cytokine IL-6, and dissolution rate in simulated lung fluid. Materials selected in the
screening phase will be used for more detailed, mechanistic studies. The second phase will test selected mate-
rials for particle uptake by the cells, for the induction of additional cytokines, and for the effect of antioxidants.
Phase two physical characterization will include electron microscopy, BET surface area, zeta potential, and
trace element analysis. In the third phase, the most inflammatory and most benign nanomaterials will be used
in hypothesis-based toxicology experiments to evaluate plausible mechanisms by which the particles induce
specific responses in cells. Cell culture toxicology studies with BEAS-2B cells, an immortalized human lung
epithelial cell line, are emphasized and are consistent with the goal of refining, reducing, and replacing animal
use. To establish the relevance of cell culture data to whole animals and to human health, experiments using
normal macrophages and normal epithelial cells that are freshly harvested from rats will be conducted to test
the ability of the cell culture assays to predict the induction of inflammation by specific nanomaterials.
The vendors' nominal size of selected powders sold as nanomaterials has been verified (Figure 2). Some su-
permicron size particles appear to have internal porosity. The tentative result of the in vitro assays used in the
screening phase is that the nano-size particles of metal oxides are not highly potent as compared to micron-
sized particles of the same compound or compared to positive controls that are representative of environmental
particulate matter. This may be good news for those concerned about the potential health effects from nanopar-
ticles in consumer products, but much more work is needed to confirm these results before publication.
This is the first year of a 3-year study. Verification of the relatively low potency of nano-sized particles will be
added to the cell culture and physical characterization studies already planned.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop 111
Suspended by yort eiing *
imrrwdateiy befoJO use
LHC-9 Madia
B£AS;2B cells
Apply particles or
- eiherneitmcntiA:
.culture media:
> Harvest Media
for ELBA Assay; '
Replace media
"'for Cell Viability As*»y. '
Figure 1. Using in vitro cell culture to measure cytotoxicity of and 1L-6 induction by a range of nario-
and micro-sized particles.
Nominal Mterpn and NanoPartJcki*
Surface area lr»mA2/g
1000.% ' ' ' *
^diaitMter.
- S rim .
Ce-i A!
Figure 2. BET surface area for nominal micron and nanoparticles. Bars are marked with the elemental
symbol of the metal, but particles were in the oxide form.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Nanomaterials in Drinking Water
Paul Westerhoff
Arizona State University, Tempe, AZ
Abstract
Although the current market for nanomaterials is small and their concentration may not be high enough in the
environment to cause human health or environmental problems, this market is increasing rapidly. Also, the
discharge of nanomaterials to the environment in the near future could be significant as manufacturing costs
decrease and new applications are discovered. The accumulation of nanomaterials in cells may have significant
environmental and human impacts. At present, very little is known about the fate, transport, transformation,
and toxicity of these man-made nanomaterials in the environment. The objectives of this project are to: (1)
characterize the fundamental properties of nanomaterials in aquatic environments; (2) examine the interactions
between nanomaterials and toxic organic pollutants and pathogens (viruses); (3) evaluate the removal effi-
ciency of nanomaterials by drinking water unit processes; and (4) test the toxicity of nanomaterials in drinking
water using a cell culture model system of the epithelium. This study considers the physical, chemical, and
biological implications of nanomaterial fate and toxicity in systems that will provide insight into the potential
for nanomaterials to be present and of health concern in finished drinking water.
A multidisciplinary approach is underway that includes experiments to identify the fundamental uniqueness of
nine nanomaterial properties and toxicity, and applied experiments aimed directly at understanding the fate and
reactions involving nanomaterials in drinking water treatment plants. Advanced nanomaterial characterization
techniques will be employed to determine the size distribution, concentration, and zeta potential of nanomate-
rials in buffered distilled water and model waters representative of raw drinking water supplies. Adsorption of
dissolve pollutants (e.g., anions, metals, range of synthetic organic chemicals) and natural organic matter are
proposed to quantify the potential for nanomaterials to transport such compounds and be transformed by the
compounds (e.g., aggregation, change in zeta potential). Coagulation processes will be studied by compressing
the electric double layer of nanomaterials, and exposing nanomaterials to alum coagulations, using mono- and
heterodisperse solutions; comparable filtration work also will be conducted. Adsorption of virus onto nanoma-
terials and subsequent disinfectant shielding will be studied. Toxicity screening will include toxicity of nano-
materials on several cell lines selected to mimic oral ingestion routes in drinking water.
During the first year of this project, significant advances have been made. These have been incorporated in
numerous invited and unsolicited presentations at national conferences. The first year focused in part on meth-
odological advances. This included demonstrating that commercial nanoparticles do not behave as discrete
nanoparticles in aqueous systems, and aggregation of these materials results in particles less than 1 um. This
study has focused on metal oxide nanoparticles and understanding how surface change (zeta potential) affects
the removal of nanoparticles during simulated drinking water treatment. Coagulation and sedimentation proc-
esses remove 30 to 80 percent of the nanoparticles, meaning that many would not be removed. Second, ex-
periments with inorganic (arsenic) and organic (MIB) chemicals or pathogen models (MS2 bacteriaphage)
have concluded that surface change will affect the extent of interaction, and nanoparticles can facilitate the
transport of these substances. Third, conditions conducive to growing various epithelial cell layers that mimic
intestinal cell linings have been developed. Using resistivity-based approaches, a detrimental impact of
nanoparticles has been observed, and using confocal laser microscopy it has been observed that nanoparticles
penetrate the cell membranes. Over the next 2 years, this study will be expanded to include quantum dots and
other nanoparticles in greater detail.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop 111
Microbial Impacts of Engineered Nanoparticles
Pedro J.J. Alvarez and Mark R. Wiesner
Rice University, Houston, TX
Abstract
Responsible usage of nanomaterials in commercial products and environmental applications, and prudent man-
agement of the associated risks, require an understanding of nanoparticle mobility, bioavailability, and ecotoxi-
cology. This project will elucidate.processes governing the transport and microbial impacts of two classes of
catalytic nanomaterials in soil-water systems: fullerenes and metallic nanoparticles (e.g., TiC>2, ZnO, and Fe
(0)). Specific tasks are to: (1) characterize nanomaterials size, shape, functionality, reactivity, aggregation,
deposition potential, and bioavailability; (2) screen nanomaterials of varying sizes and properties for bacteri-
cidal activity; (3) discern bacterial physiologic characteristics that confer resistance (or susceptibility) to cata-
lytic nanomaterials; (4) evaluate the potential for fullerene biotransformation by reference bacteria and fungi;
and (5) assess the impact of simulated nanomaterial releases on microbial diversity and community structure.
The researchers postulate that reactivity at the nanometric scale is intimately linked to nanoparticle mobility
and microbial sensitivity. Thus, first-order factors increasing nanoparticle reactivity should increase the rate of
redox reactions with second-order effects on particle mobility and ecotoxicity. Sources of reactivity may in-
clude functionalization of nanoparticle surfaces, affinity for electron uptake and subsequent transfer to species
in solution, and interfacial phenomena ranging from ordered water effects such as clathrate formation around
nano-particle nuclei to adsorption of naturally occurring macromolecules. Regarding microbial impacts, it is
hypothesized that nanomaterials that generate reactive oxygen species or related free radicals will hinder het-
erotrophic and photosynthetic activities and cause population shifts that reflect differential responses and di-
verse protective mechanisms used by dissimilar populations. Thus, aerobic bacteria with enzymes that destroy
toxic oxygen species or with thicker cell walls may have a competitive advantage. Similarly, fermenting bacte-
ria may be more resistant than respiring or photosynthetic bacteria, because the latter employ many bio-
molecules to transfer electrons during phosphorylation, which could interact with catalytic nanomaterials to
generate harmful free radicals.
Regarding experimental approach, a risk assessment structure will be followed to examine factors that affect
nanoparticle exposure and impact. Nanoparticle exposure will be quantified in terms of mobility in soil-water
systems. Microbial impact will be quantified as a function of nanomaterial properties and bacterial physiologi-
cal characteristics, by measuring cell growth, respiratory, photosynthetic, and enzymatic activities. Molecular
tools will be used to characterize effects on microbial community structure. The interface between exposure
and impact will be examined in both batch reactors and in flow-through column experiments.
The relevance of the proposed work to the U.S. Environmental Protection Agency's mission is related to the
fact that microorganisms are the foundation of all ecosystems and are often the basis for food chains and the
main agents of biogeochemical cycles. Thus, understanding their interactions with engineered nanomaterials is
important to ensure that nanotechnology improves material and social conditions without exceeding the eco-
logical capabilities that support them. This research will provide an improved understanding of the chemical
and physical factors that control nanoparticle mobility and bioavailability, and their impacts on microbial ac-
tivities, diversity, and community structure. This will benefit risk assessment and management efforts, and
may contribute indirectly to the development of nanotechnology-based disinfection and biofouling control
strategies.
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Nanotechnology and the Environment; Applications and Implications Progress Review Workshop III
Semiconductor Nanowires and Applications to Human Health
Ray LaPierre
IdcMaster University, Hamilton, Ontario, Canada
Abstract
This project addresses the growth and applications of semiconductor nanowires by molecular beam epitaxy
using a technique called the vapor-liquid-solid (VLS) process. The VLS process uses a catalytic seed particle
that spatially confines the nucleation processes responsible for semiconductor growth. Using this approach,
single wires less than 10 nanometers in diameter and as long as tens of microns have been produced. By alter-
ing the conditions of wire growth, complex heterostructures may be incorporated into the wires adding opto-
electronic functionality for biological applications of interest to human health, including solution assays, fluo-
rescent labeling, optical barcoding, separation, delivery, and biosensing. The physicochemical properties of
semiconductor nanowires will be studied to develop an understanding of their potential toxicological and bio-
logical impact. The capabilities of the VLS process will allow, for the first time, a systematic study of the size-,
shape- and composition-dependence of the transport properties of nanoparticles and their cellular interactions.
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Interactions Between Semiconductor Nanoparticles
and Biomembranes and DMA
Jay Nadeau
McGill University, Montreal, Quebec, Canada
Abstract
Two very different modes of access have been identified, one in bacteria and one in mammalian cells. Both
are dependent on the physical chemistry of the particle.
In Bacteria. Bacteria do not endocytose; thus, they are unlikely to be able to take up particles several nanome-
ters in size unless there is a particular mechanism permitting these particles to penetrate. The researchers have
identified two features critical for uptake in bacteria. First, the quantum dots (QD) must be conjugated to a
biomolecule to which the bacterium has receptors, and the conjugation must not interfere with the recognition
site of that molecule. Second, the QD must be readily photooxidized, and light exposure must occur during
incubation with the bacteria. Certain biomolecules, such as the purines adenine and guanine, the neurotransmit-
ter dopamine, and the amino acids tyrosine and tryptophan, make the QDs more effective at this light-induced
cell penetration. Penetration is through membrane defects in the cell surface; however, treated bacteria do not
show membrane compromise or associated cell death.
In Mammalian Cells. The presence of specific receptors to the QD conjugate is required for uptake. Light ex-
posure is not required, consistent with endocytic mechanisms of uptake. QDs can be visualized in cellular en-
dosomes, and endosomes can be ruptured by exposure to ultraviolet (UV) light.
In All Cells. Surprisingly, even cells that endocytose show preferential uptake of certain colors (sizes) of QD.
This is correlated with the ability of the different sizes to transfer electrons or holes to their conjugates.
Reactivity. With membranes, hydrophobic QDs, capped with pyridine, show integration into biomimetic lipid
membranes and can be delivered (with the aid of a surfactant) to the membranes of living cells. Surprisingly,
the application of large voltages (± 120 mV) and exposure to high-intensity UV light (Hg lamp, 60 min) are
not sufficient to produce any measurable leakage events. Hydrophilic QDs, however, capped with mercapto-
acetic or mercaptoproprionic acids, create fast leakage events suggesting penetration through lipid membranes.
Exposure to large voltages appears to be necessary to begin the process; after leakage events have begun,
smaller voltages (± 20 mV) are sufficient to evoke additional events. Events are nonquantal and do not require
light exposure.
With DNA. DNA damage by QDs appears to be related to Cd release after photodegradation of particles. Se-
vere effects on bacterial growth were seen whenever bare core CdSe QDs were assimilated, especially in Gram
positive strains. Growth using measurements of cell density (optical density at 600 nm), by inspection under
epifluorescence microscopy (to investigate cell morphology, spore formation, and QD-related fluorescence),
by plating, and by quantitative analysis for hydroxyguanine were investigated. When QDs were added to Gram
positive Bacillus cultures in early log phase (OD 600 < 0.2), optical density decreased, indicating cell loss, and
endospores could be visualized (n > 10). When incubation was begun at mid-log phase, OD continued to in-
crease, but more slowly than in controls: percent of control at 2 h, 60 ± 2 percent; at 6 h, 39 ± 3 percent (n = 3).
The cells, however, were unable to form colonies (n = 5; dilutions ranged from 1:5 to 1:1 for cultures of OD
600 between 0.3 and 0.5). Extraction of genomic DNA and assays for oxidative DNA damage showed an aver-
age of 7.75 ± 0.006 abasic sites per 105 base pairs in Bacillus subtilis cells exposed to yellow QD-adenine (n =
6). B. subtilis exposed to cell-wall targeted (nonassimilated) QDs under room light showed 2.33 ± 0.005
abasic sites per 105 base pairs (n = 3).
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
With CdSe/ZnS core-shell QDs, less than I abasic site was seen per 105 base pairs. However, much less QD
assimilation was observed in this case: two-fold weaker fluorescence using particles with a fifteen-fold greater
quantum yield. Hence, it is possible that Cd release assists particle uptake.
Stability. The QD conjugates used in this study have all linked a biomolecule to the QD surface cap via an am-
ide bond. Proteases in cellular lysosomes break these bonds, liberating the QD from its conjugate. Small con-
jugates can thus diffuse out of the lysosomes and into the cell. Using QD-dopamine, this process may be di-
rectly observed as oxidized dopamine and shows blue fluorescence.
Prolonged exposure to light and oxidizing conditions do not appear to lead to significant release of Cd from
CdSe/ZnS core-shell particles. Ion chromatography/mass spectrometry (ICP-MS) revealed less than 1 ppm Cd
in aqueous solutions of core-shell dopamine conjugates after 4 hours of UV exposure. The addition of antioxi-
dants to these solutions (beta-mercaptoethanol or ascorbic acid) reduced the Cd release to less than 20 ppb.
Conclusions and Future Work, The photophysics of QDs, particularly their size, redox potential (which de-
pends not only on band gap, but on the presence of surface states) has a great influence on the interactions of
these particles with biological cells and structures. Electron transfer processes should be sought as causes of
selective uptake of specific sizes of QDs. Common biomolecules can also sensitize QDs, making them more
photoreactive and able to damage cell membranes with or without'Cd release. DNA damage, however, has so
far only been seen when Cd is released in significant quantities.
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Interactions Between Semiconductor Nanoparticles
and Biomembranes and DNA
Jay Nadeau
McGill University, Montreal, Quebec, Canada
Environmental Implication/Application
Risk of Photosensitized Quantum Dot Particles Released Into Water/Soil
QDs conjugated to electron donors are photosensitized (i.e., they are more reactive on exposure to light than
unconjugated particles or particles conjugated to molecules, which cannot donate electrons). Such conjugates
cause extreme oxidative phototoxicity to cells to which they are able to bind, whether these cells are mammal-
ian, fungal, or bacterial. Thus, an important conclusion of this project is that such QD conjugates should be
treated very differently from bare QDs, as they are likely to be significantly more hazardous.
In addition, this study shows great variation in reactivity and ability to be photosensitized among the different
sizes (colors) of QDs. These effects cannot yet be quantitatively predicted theoretically, as they are dependent
on factors other than the particle diameter or band gap. Thus, it is expected that the risks of different sizes of
semiconductor nanocrystals will have to be determined independently.
Highly reactive, photosensitized particles should be prevented from entering any potential food or water sup-
plies, particularly because they can show reactivity to particular cell types.
Risk of Exposure to Specific Cell Types
QD-dopamine conjugates are specifically taken up by dopamine-receptor bearing cells. This could pose a sig-
nificant risk in animals if these particles were able to come into contact with such cells. Experiments with
mouse or other animal models are needed to assess these risks.
Usefulness as Targeted Microbicides
Photosensitized particles targeted to bacterial metabolism have potential as microbicidal agents. However,
most of the toxicity observed in bacteria in this study appeared to be related to Cd release, which is undesir-
able. The creation of highly phototoxic, bacterially targeted particles capped with ZnS or other non-Cd con-
taining layers remains a challenge for the future.
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Understanding the Light-Induced Cytotoxicity of Quantum Dots:
A Cellular, Photophysical, and Mechanistic Approach
Franyoise Winnik
University of Montreal, Montreal, Quebec, Canada
Abstract
Quantum dots (QDs), nanometer-sized light emitting semiconductor (i.e., CdSe) particles, are emerging as a
new class of fluorescent probes for in vivo and cellular imaging. Due to their size, they have unique optical
properties such as size-tunable emission from green to red, resistance to photo bleaching, and high emission
quantum yield. Two decades ago, QDs were confined to physicists' laboratories. In 2005, QDs are com-
mercially available worldwide in numerous forms. They are used in bioimaging, either perse or conjugated to
biopolymers, DNA, and proteins, thus enabling target-specific imaging. They can act as an energy donor in
FRET experiments and, as demonstrated recently, they also can be used as photosensitizers. The latter property
is particularly exciting because it could lead to novel forms of in vivo photodynamic therapy.
Not surprisingly, the potential toxic effects of semiconductor QDs have become a topic of considerable impor-
tance and discussion. Indeed, in vivo toxicity is likely to be a key factor in determining whether QD imaging
probes would be approved by regulatory agencies for clinical human use. Recent publications by the research-
ers and by others indicate that QDs can be highly toxic to cells under irradiation, although under given condi-
tions QDs are much more benign. This research project focuses on the light-induced potential toxicity of QDs,
using a three-pronged mechanistic approach: solution photophysics, cell imaging, and quantitative analysis of
released harmful ions (Cd2+).
The outcome of this study will be to gain a better understanding of a key aspect of QD cytotoxicity, an ap-
praisal of various means to alleviate their deleterious effects, and the delineation of predictive guidelines for
QD cytotoxicity.
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Section 9. Exposure
As nanotechnology progresses from research and development to commercialization and use, it is likely that
manufactured nanomaterials and nanoproducts might result in exposure to humans or other organisms. Po-
tential sources of human exposure to nanomaterials include workers exposed during the production and use of
nanomaterials, general population exposure from releases to the environment during the production, use and
recycle/disposal of nanomaterials, and direct general population exposure during the use of commercially
available products containing nanoscale materials. Research is needed to identify potential sources, pathways,
routes of exposure, potential tools and models that may be used to estimate exposures, and potential data
sources for these models. Tools and resources for assessing releases and exposures, including metrics and
sensors, analysis of physical and chemical properties of nanomaterials, and population sensitivities need to be
developed, along with engineering controls and pollution prevention techniques capable of minimizing releases
and exposures to nanomaterials.
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Nanomaterial Interactions With Skin
Nancy A, Monteiro-Riviere and Jim E. Riviere
Center for Chemical Toxicology Research and Pharmacokinetics,
North Carolina State University, Raleigh, NC
Abstract
The field of nanoscience has experienced unprecedented growth during the last few years and has received a
great deal of attention because of the many potential applications. Nanomaterials possess unique physico-
chemical properties compared to larger microparticles that enable novel engineering applications. Their large
surface area and increase in reactivity can enhance the transport of nanomaterials in the environment and in
biological systems. There are many challenges, however, that must be overcome before nanotechnology can be
applied to the field of nanomedicine or science-based occupational or environmental exposure risk assessments
can be conducted. There is a serious lack of information about human health and environmental implications of
manufactured nanomaterials. This new field of nanotoxicology will continue to grow and emerge as new prod-
ucts are produced. Insufficient data have been collected so far to allow for full interpretation or thorough un-
derstanding of the toxicological implications of occupational exposure or potential environmental impact of
nanomaterials.
Skin is a primary route of potential exposure to toxicants and nanomaterials, and the ability to traverse the stra-
tum corneum and viable epidermal layers is a primary determinant of the dermatotoxic potential. Currently,
there is no information on whether carbon nanomaterials, or nanomaterials in general, can penetrate intact skin
and cause adverse effects.
The goal of this research project was to study the effects of several different types of nanomaterial interactions
with skin, including dermal absorption and cutaneous toxicity and the ability to distribute to skin after systemic
exposure. To date, several types of nanomaterials have been evaluated in two different in vitro model systems
under different conditions (concentration, surfactants, and vehicles); multi-walled carbon nanotubes
(MWCNT) in human epidermal keratinocytes (HEK), the fullerenes nanoC«> and derivatized C«> {C6o(OH)24)
in HEK. Also, fullerene-based amino acids (BAA) and fullerene C«o peptide with a fluorescently tagged nu-
clear localization signal (NLS-FITC) for 24 h and 48 h in HEK have been evaluated. In addition, quantum dots
(QD) of two different sizes (6 nm and 10 nm) and three different surface coatings (polyethylene glycol, car-
boxylic acid, or amine) have been evaluated. All of these studies were conducted in HEK to assess cellular
uptake, cytotoxicity, and inflammatory potential. The fullerene NLS-FITC and QD also were evaluated in
flowthrough diffusion cells to assess skin penetration.
HEK were exposed to 0.1, 0.2, and 0.4 mg/mL of multi-walled carbon nanotubes (MWCNT) for 1, 2, 4, 8, 12,
24, and 48 h. HEK were examined by transmission electron microscopy (TEM) for the presence of MWCNT.
This study showed that chemically unmodified MWCNT were present within cytoplasmic vacuoles of the
HEK at all time points. The MWCNT also induced the release of the proinflammatory cytokine interleukin 8
(IL-8), a biomarker for skin irritation, from HEK in a time-dependent manner. These data clearly show that
MWCNT, neither derivatized nor optimized for biological applications, are capable of both localizing within
and initiating an irritation response.
Studies with the fullerenes nanoC6o, and derivatized Cso (C6o(OH)24) were conducted in HEK. HEK were ex-
posed to nanoCeo ranging in concentrations (0.0000025 - 0.0005 mg/mL), derivatized C6o (C6o(OH)24) ranging
in concentrations (0.000005 - 0.001 mg/mL) (n=8/treatment) for 24 h and 48 h. MTT viability showed nano-
C60 ranging from 0.00025 to 0.0005 mg/mL decreased HEK viability significantly (p < 0.05) by 24 h. The in-
flammatory mediators IL-8 and IL-6 were significantly (p < 0.05) greater than controls, but IL-10, IL-lp, and
TNF-a were below detectable limits. C
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
48 h. Additional studies with 0.5 percent Pluronic F127 surfactant found that.nano-C60 (0.0005 mg/mL)
caused a significant (p < 0.05) decrease in viability and a significant increase in IL-8 production by 48 h. In
contrast, C6o(OH)z4 treated with the surfactant showed no statistical differences in HEK viability or cytokine
production. Finally, the addition of 1 percent DMSO to nano-C6o (0.0005 mg/mL and 0.003 mg/mL) signifi-
cantly decreased MTT viability, and the 0.003 mg/mL significantly increased the release of IL-8 by 48 h.
These results show that although derivatized C6o(OH)24 are nontoxic in the tested range, nano-C^o are toxic at
concentrations as low as 0.00025 mg/mL in HEK.
The amino acid derivatized fullerene C6o BAA has the potential to provide greater interaction between the
fullerene and the biological environment yielding potential new medical and pharmacological applications.
BAA can serve as a nanoparticle platform for conjugation of targeting peptides and therapeutic biomolecules.
HEK were exposed to fullerene BAA concentrations of 0.4 - 0.00004 mg/mL for 1, 4, 8, 12, 24, and 48 h.
MTT cell viability after 48 h significantly decreased (p < 0.05) at concentrations of 0.4 and 0.04mg/mL. Proin-
flammatory cytokines IL-6, IL-8, TNF-a, IL-1B, andJL-10 were assessed at concentrations ranging from 0.4 -
0.004 mg/mL. IL-8 concentrations for the 0.04 mg/mL treatment were significantly greater (p < 0.05) than all
other concentrations at 8, 12, 24, and 48 h. IL-6 and IL-lli activities were greater at the 24 h and 48 h for 0.4
and 0.04 mg/mL. No TNF-a or IL-10 activity existed at any time points for any of the concentrations. These
results indicate that concentrations lower than 0.04 mg/mL initiate less cytokine activity and maintain cell vi-
ability at control levels. BAA concentrations of 0.4 and 0.04 mg/mL in HEK decreases cell viability and can
initiate a proinflammatory response in the dominant cell type of skin.
HEK also were exposed to concentrations from 0.4 - .001 mg/mL (n = 8/treatment) of CsoBAA conjugated to a
peptide with a fluorescently tagged nuclear localization signal (NLS-FITC) for 24 h and 48 h. MTT viability
and the proinflammatory mediator's interleukin IL-8, IL-6, IL-lp1, IL-10, and TNF-a were assessed. In addi-
tion, 4.4 ug/cm2 and 1.1 fig/cm2 of C60-NLS-FITC with and without 1 percent Pluronic® surfactant or NLS-
FITC alone was topically applied to porcine flow through diffusion cells for 24 h. MTT viability decreased and
was statistically significant (p < 0.05) in HEK at 0.4 mg/mL at both 24 h and 48 h. IL-8 and IL-6 statistically
increased at 0.2 mg/mL and 0.4 mg/mL. IL-1|3 (0.4 mg/mL) was low but was significantly different from con-
trols, while IL-10 and TNF-a were below detectable limits. Confocal microscopy of the flow through skin at
both concentrations for Ceo-NLS-FITC and NLS-FITC depicted penetration through all epidermal layers. Sur-
factant greatly enhanced the permeability for all treatments. These results showed that the substituted fullere-
nes can penetrate through intact skin and can elicit an inflammatory response.
QDs of two different sizes (6 nm and 10 nm) and three different surface coatings (polyethylene glycol, carbox-
ylic acid, or amine) were topically applied to porcine skin in flow through diffusion cells at a concentration of
62.5 pmoles/cm2. Confocal microscopy showed QDs were localized within the epidermis and dermis by 24 h
for all QD preparations. Additional studies utilized HEK to investigate the cellular uptake, cytotoxicity, and
inflammatory potential of these nanomaterials. Live cell confocal imaging showed that all types of QDs were
localized within the cell by 24 h. MTT viability and multiplex ELISA for the inflammatory cytokines IL-lp,
IL-6, IL-8, IL-10, and TNF-a revealed that carboxylic acid-coated QDs at a concentration of 20 nM exhibited
significant cytotoxicity and increased release of IL-8 by 24 h. This study showed that commercially available
QDs with diverse surface chemistries can penetrate the skin and be incorporated within HEK by 24 h, and that
QD surface coatings can influence cytotoxic and inflammatory effects.
These ongoing studies and the results so far indicate that skin cells and intact skin exposed to nanoscale mate-
rials of different physicochemical properties such as size and surface charge, and different vehicles may result
in localized toxicity. The dermatotoxic potential of nanomaterials is based on whether they can traverse
through the stratum corneum layers, penetrate through the viable epidermal layers to the dermis, and be ab-
sorbed by the capillaries in the dermal papillary layer to have a systemic effect. These data are necessary to
define the doses for systemic exposure after topical administration as well as the cutaneous hazard after either
topical or systemic exposure, the two essential components of any risk assessment. If nanomaterials are inad-
vertently modified or if exposure occurs before cleansing, they could have untoward consequences if they gain
entry through the skin. A single study will not definitively answer all of the pertinent questions relative to
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
dermal risk assessment of nanomaterials, but they provide a foundation for future work. Ultimately, they
should be able to provide an insight into the nature of the potential hazard of nanomaterials at certain concen-
trations and under various conditions and should provide an initial estimate of the dermal exposure parameters
that can be used to design more definitive studies.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
II alveolar epithelial cells were used that are stably transfected with a luciferase reporter located in the pro-
moter region for the interleukin (IL)-8 gene. Luciferase reporter activity is, thus, used as an indicator of oxida-
tive stress in these cells. Some of the Pt shapes using this cell culture system have been tested; dose-related
responses to Pt flowers and multipods were assessed. There was a small dose-dependent (0-500 ug/well; 0-24
(xg/cm2) increase in reporter activity with the flowers and not the multipods that was not related to increased
LDH release (Figure 2).
In addition to contact with the epithelium, the researchers further suggest that NPs can move from the epithe-
lial surface in the alveoli to gain access to the blood, thus interacting with endothelial cells. Studies have been
initiated using cultured human umbilical vein endothelial cells (HUVECs) to investigate the effects of NP ex-
posure on endothelial target cells. A dose-related increase in IL-6 release has been observed in response to col-
loidal Au (12-188 ug/well; 0.6-8.9 ng/cm2) from passage 4 through 10 without accompanying changes in LDH
(Figure 3); this increase was manifested in more than a doubling of IL-6 release from low to high-dose nano-
Au (20 nm). Interestingly, these changes occurred in the presence of BSA coating and despite the fact that the
coated Au NPs appeared to agglomerate within the first hour of culture at 37 °C. The responses to the Au col-
loids were slightly higher than those to ultrafine TiOj, which was used at a higher dose range (and caused in-
creases in LDH release). Exposed HUVEC were embedded in gelatin and then sectioned for EM analyses.
Subsequently, Au NP singlets and agglomerates were found in these cells (Figure 4), particularly in lysosomes.
The individual NPs are approximately 20 nm in diameter. The researchers plan to test the Pt shapes using this
cell culture system.
The research efforts will focus over the next several months on in vitro analyses of NP effects and move to in
vivo evaluations by the middle of the calendar year. The specific activities that are planned for the immediate
future include the following: -(I) continue work to define the conditions under which agglomeration occurs;
and (2) continue studies on cellular uptake of various NPs using chemical detection and microscopic methods
to determine if uptake is required to produce oxidative stress. The results of the studies will provide dose-,
size-, and composition-related lexicological information about nanoparticles. The insight gained regarding
mechanisms of response to nanoparticles and their disposition after exposure can be used to predict outcomes
of human exposures in environmental, occupational, and therapeutic settings.
Summary: ROS Activity
50i
>
3
30\
O
a
**
.1
20
10
0.1
Panicle
Type ii»
-•-TiOj (D) 20rm
"••TiO2(F) 200 n
-j* TiOj (M)
-O Pt-PALAS 35nm
-•-Pt-Spheres 17l
-9-Pi Pods 17
-*-Copper 40
-*-Copper 60
-*-Copper so
100
Figure 1. ROS-generating capacity of several metal nanoparticles, including colloidal gold and the platinum
shapes.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Luciferase Activity in AS49 Reporter Cells following
Exposure to Ft Nmoparticlei
Control TNF/10 50 m ISO w 500 (is SO ug ISO fit SOD u(
(10 m)
Pt Rowers
PtMuttipods
UJH Relewe by A549 Ludfenue Reporter Cells following
Exposure to Pt Nanoparticles
Control TNF SO« 1SO|1| SOO u( 50pg 150 M 500 (ij
(tOn|)
PI Flowers
PtMuttipods
Figure 2. Activation of the IL-8 gene (luciferase
reporter activity) in stably transfected
A549 lung epithelial cells (top) and LDH
release (bottom).
IK Rekue by HUVEC after Eipo>yre to UllrafineTiO, (M
>•) or BSA-coaUd Colloidal Gold Nanoparticlei (20 nm)
1200
200
0
Contra! 25 H 100 MI 400 U( U Uf 47|lf III Uf
Ultr.fio.TiOj
Nuiogold
LDH Release by HUVEC alUr Eiposure to Ultrafine TiO j (20
nm) or BSA-coated Colloidal Gold Nanoparticles <2oin)
100,
Control IS jig 100 (l» 400 |ts IZ||| 47 |i|
Ullra(ln« TiO,
Nanogold
Figure 3. IL-6 (top) and LDH (bottom) re-
lease by HUVECs, example from
Passage 4 cells.
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Figure 4. EM image of a section from a gelatin-embedded HUVEC exposed to 20 nm colloidal Au.
Individual particles are 19-20 nm in diameter.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Effects of Nanomaterials on Human Blood Coagulation
Peter L. Perrotta1 and Pelagia-Irene (Perena) Gouma2
'West Virginia University, Morgantown, WV;
2State University of New York at Stony Brook, Stony Brook, NY
Abstract
Common and serious human diseases such' as myocardial infarction and stroke are caused by abnormalities of
blood coagulation that predispose to thrombosis (clots). These diseases are clearly influenced by environ-
mental factors. Because of their large surface area and reactivity, nanomaterials that enter the workplace or
home have the potential to adversely affect blood coagulation, which could result in abnormal clotting and/or
bleeding.
Thus, a comprehensive approach will be used to study how a wide-range of commercially prepared nanomate-
rials affect human blood coagulation. Techniques will focus on the two major components of the clotting sys-
tem, namely, blood coagulation proteins and platelets. First, the effects of nanomaterials on blood clotting pro-
teins will be studied using coagulation-specific laboratory assays. This project will focus on the ability of
nanomaterials to promote and/or retard the catalytic activity of coagulation enzymes. This is because adsorp-
tion of enzymes on the extensive available surface of nanomaterials may alter the functional groups of the en-
zymes and hence, their enzymatic activity. Next, classes of nanomaterials will be identified that "activate" hu-
man platelets because platelet activation plays a role in many thrombotic diseases. Finally, the complex inter-
actions between blood coagulation elements and nanomaterials will be characterized at the molecular level.
Research findings will be used to: (1) identify nanomaterials that can harm human coagulation; (2) determine
nanomaterial thresholds of toxicity and dose-response effects on clotting proteins; and (3) classify engineered
nanomaterials based on their physiologic effects on blood coagulation.
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Assessment Methods for Nanoparticles in the Workplace
Patrick T. O'Shaughnessy
University of Iowa, Iowa City, IA
Abstract
The primary objectives of this study are to: (1) provide the scientific community and practicing industrial hy-
, gienists with verified instruments and methods for accurately accessing airborne levels of nanoparticles; and
(2) assess the efficacy of respirator use for controlling nanoparticle exposures. These objectives will be
reached through a combination of laboratory and field-based studies centered on the following specific aims:
(1) identify and evaluate methods to measure airborne nanoparticle concentrations; (2) characterize nanoparti-
cles using a complementary suite of techniques to assess their surface and bulk physical and chemical proper-
ties; and (3) determine the collection efficiency of commonly used respirator filters when challenged with
nanoparticles.
The research approach will involve both laboratory and field work. Manufactured nanomaterials covering a
range of the types available will be obtained from several sources. Measurements obtained from a variety of
sampling instruments, including a novel passive aerosol monitor, wil! be systematically compared relative to
measurements made by transmission electron microscopy (TEM) under controlled laboratory conditions. Field
tests will involve the use of the instruments analyzed in the laboratory to quantify and characterize nanoparti-
cle concentrations in workplaces that manufacture and/or use nanoparticles. This study also will provide the
opportunity to refine an aerosol mapping technique that the researchers have developed to visualize the tempo-
ral and spatial variability of aerosol concentrations in a workplace. Laboratory testing will be conducted to
determine the collection efficiency of respirator filters when challenged with a variety of nanoparticle types.
The surface properties and chemical composition of a number of nanoparticle types will be analyzed to deter-
mine whether these qualities can aid in establishing the cause of differences in instrument performance and
filtration efficiency when challenged with different nanoparticles, as well as to aid in the recognition of un-
known nanoparticles encountered in a workplace or in the ambient environment.
This work is an essential first step needed to accurately identify the hazards associated with a new workplace
health threat. The expected results from these studies will include a greater understanding of the strengths and
limitations of instruments capable of evaluating nanoparticle exposure levels. The assessment of physical and
chemical features of nanoparticles will aid in identifying nanoparticle qualities that affect instrument perform-
ance and filtration efficiency. Moreover, this work will result in guidance on the use of respirators to protect
against nanoparticle inhalation in the workplace.
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Appendix
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Nanotechnology and the Environment: Applications and Implications
Progress Review Workshop III
October 26 - 28, 2005
Holiday Inn Rosslyn at Key Bridge
1900N. Fort Myer Drive
Arlington, VA 22209
AGENDA
DAY I: Wednesday, October 26,2005
Plenary Session - Rosslyn Ballroom
10:00 a.m. Registration
10:30 a.m. Welcome
William Farland, Acting Deputy Assistant Administrator for Science, Office of Research
and Development (ORD), USEPA
10:50 a.m. Overview of Canadian Nanotechnology
Paul Dufour, Senior Advisor International Affairs, Office of the National Science Advisor,
Privy Council Office, Government of Canada
11:10 a.m. Overview on the National Nanotechnology Initiative
Mihail Roco, Co-Chair, National Science and Technology Council
12:00 p.m. Overview on Canadian Institute of Health Research
Eric Marcotte, Canadian Institute of Health Research
12:20 p.m. Lunch
1:45 p.m. Overview on EPA and Nanotechnology
Barbara Karn, USEPA, Detailed to Project on Emerging Nanotechnologies, Woodrow
Wilson International Center for Scholars at The Smithsonian Institution
2:15 p.m. Overview on Applications of Nanotechnology
David Rejeski, Director, Foresight and Governance Project, Woodrow Wilson Center
2:45 p.m. Break
3:10 p.m. Grant Presentations
Track A - Rossyln Ballroom
Nanostructured Microemulsions as Alternative Solvents to VOCs in Cleaning
Technologies and Vegetable Oil Extraction
Anuradee Witthayapanyanon and Linn Do, University of Oklahoma
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Sustainable Biodegradable Green Nanocomposites From Bacterial Bioplastic for
Automotive Applications
Manjusri Misra, Michigan State University
James Kilduff, Rensselaer Polytechnic Institute
Ecocomposites Reinforced with Cellulose Nanoparticles: An Alternative To Existing
Petroleum-Based Polymer Composites
William Winter, Syracuse University
Evaluating the Impacts of Nanotechnology via Thermodynamic and Life Cycle Analysis
Bhavik Bakshi, Ohio State University
Crass-Media Transport, Transformation, and Fate of Carbonaceous Nanomaterials
Linsey Marr, Virginia Polytechnic Institute and State University
Fate and Transport of Ceo Nanoparticles in Unsaturated and Saturated Soils
Kurt Pennell, Georgia Institute of Technology
Grant Presentations Track B - Georgetown Room
Applications of Nanoscale Tunable Biopolymers for Heavy Metal Remediation
Ashok Mulchandani, University of California, Riverside
A Bioengineering Approach to Nanoparticle-Based Environmental Remediation
Daniel Strongin, Temple University
Interactions Between Semiconductor Nanoparticles and Biomembranes and DNA
Jay Nadeau, McGill University
Uptake and Toxicity of Metallic Nanoparticles in Freshwater Fish
Nancy Denslow, University of Florida
Assessment of the Environmental Impacts of Nanotechnology on Organisms and
Ecosystems
Jean-Claude Bonzongo, University of Florida, Gainesville
Advanced Nanosensors for Continuous Monitoring of Heavy Metals
Omowunmi Sadik, State University of New York, Binghamton
5:00 p.m. Adjourn
6:30 p.m. Dinner
DAY 2: Thursday, October 27, 2005
Plenary Session - Rosslyn Ballroom
8:20 a.m. Perspective
Andrew Maynard, Science Advisor, Project on Emerging Nanotechnologies, Woodrow
Wilson International Center for Scholars at The Smithsonian Institution
8:45 a.m. European Commission
Pilar Aguar, European Commission
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
9:00 p.m. Grant Presentations
Track A - Rossyln Ballroom
Compound Specific Imprinted Nanosphers for Optical Sensing
Barry Lavine, Oklahoma State University
Low-Cost Organic Gas Sensors on Plastic for Distributed Environmental Sensing
Vivek Subramanian, University of California, Berkeley
Nanosensors for Detection of Aquatic Toxins
Robert Gawley, University of Arkansas
Ultrasensitive Pathogen Quantification in Drinking Water Using High Piezoelectric PMN-
PT Microcantilevers
Wan Shih. Drexel University
Grant Presentations Track B - Georgetown Room
Nanostructured Catalytic Materials for NOX Reduction Using Combinatorial Methodologies
Selim Senkan, University of California, Los Angeles
Nanoscale Bimetallic Particle for In Situ Remediation
Wei-xan Zhang, Lehigh University
Functional Fe(0)-Based Nanoparticles for In Situ Degradation of DNAPL Chlorinated
Organic Solvents
Gregory Lowry, Carnegie Mellon University
Elemental Composition of Freshly Nucleated Particles
Murray Johnston, University of Delaware
10:20 a.m. Break
10:40 a.m. Grant Presentations (Continued)
Track A - Rossyln Ballroom
Nanomaterial-Based Microchip Assays for Continuous Environmental Monitoring
Joseph Wang, Arizona State University
Metal Biosensors: Development and Environmental Testing
Anne Anderson, Utah State University
Conducting-Polymer Nanowire Immunosensors Array for Microbial Pathogens
Ashok Mulchandani, University of California, Riverside
The Bioavatlability, Toxicity, and Trophic Transfer of Manufactured ZnO Nanoparticles: A
View From the Bottom
Paul Bertsch, University of Georgia
Hysteretic Accumulation and Release of Nanomaterials in the Vadose Zone
Tohren Kibbey, University of Oklahoma
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Fate and Transformation of CSo Nanoparticles in Water Treatment Processes
Jaehong Kim, Georgia Institute of Technology
Grant Presentations Track B - Georgetown Room
Iron Oxide Nanoparticle-lnduced Oxidative Stress and Inflammation
Hong Yang, University of Rochester
Health Effects of Inhaled Nanomaterials
Ting Quo, University of California, Davis
Repercussion of Carbon Based Manufactured Nanoparticles on Microbial Processes in
Environmental Systems
Ronald Turco, Purdue University
A Novel Approach to Prevent Bioctde Leaching
Patricia Heiden, Michigan Technological University
Nanostructured Membranes for Filtration, Disinfection, and Remediation of Aqueous and
Gaseous Systems
Svetlana Zivanoic, University of Tennessee
Nanostructured Catalysts for Environmental Remediation of Chlorinated Compounds
Yunfeng Lu, Tulane University
Synthesis and Application of a New Class of Stabilized Nanoscale Iron Particles for Rapid
Destruction of Chlorinated Hydrocarbons in Soil and Groundwater
Dongye Zhao, Auburn University
12:08 p.m. Lunch
1:40 p.m. Grant Presentations (Continued)
Track A - Rossyln Ballroom
Dendritic Nanoscale Chelating Agents: Synthesis, Characterization. Modeling and
Environmental Applications
Mamadou Diallo, California Institute of Technology
Nanomaterial Interactions With Skin
Nancy Monteiro-Riviere, North Carolina State University
Physical and Chemical Determinants of Nanofiber/Nanotube Toxicity
Robert Hurt and Agnes Kane, Brown University
Natural Sciences and Engineering Research Council of Canada (NSERC) Nano
Innovation Platform
Peter Grutter, National SERC Nano Innovation Platform
Track B - Georgetown Room
Chemical and Biological Behavior of Carbon Nanotubes in Estuarine Sedimentary
Systems
P. Lee Ferguson, University of South Carolina
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A Focus on Nanoparticulate Aerosol and Atmospherically Processed Nanoparticulate
Aerosol
Vicki Grassian, University of Iowa
Assessing the Effect of Nanoparticle Size
Warren Chan, University of Toronto
3:00 p.m. Break
3:19 p.m. Grant Presentations (Continued)
Track A - Rossyln Ballroom
Short-Term Chronic Toxicity of Photocatalytic Nanoparticles to Bacteria, Algae, and
• Zooplankton
Chin-pao Huang, University of Delaware
Acute and Developmental Toxicity of Metal Oxide Nanoparticles in Fish and Frogs
Chris Theodorakis, Southern Illinois University
Role of Particle Agglomeration in Nanoparticle Toxicity
Lung-Chi Chen, New York University
Health Canada Overview: Foresight Activities
David Blakey, Health Canada
Responses of Lung Cells to Metals in Manufactured Nanoparticles
John Veranth, University of Utah
Understanding the Light-Induced Cytotoxicity of Quantum Dots: A Cellular, Photophysical,
and Mechanistic Approach
Francoise Winnik, Universite de Montreal
Track B - Georgetown Room
Transformations of Biologically Conjugated CdSe Quantum Dots Released Into Water
and Biofilms
Patricia Holden, University of California, Santa Barbara
Structure-Function Relationships in Engineered Nanomaterial Toxicity
Vicki Colvin, William Marsh Rice University
Chemical Fate, Biopersistence, and Toxicology of Inhaled Metal Oxide Nanoscale
Materials
Jacob McDonald, Lovelace Biomedtcal & Environmental Research Institute
Assessment Methods for Nanoparticles in the Workplace
Patrick O'Shaughnessy, University of Iowa
Mechanistic Dosimetry Models of Nanomaterial Deposition in the Respiratory Tract
Bahman Asgharian, CUT Centers for Health Research
Monitoring and Characterizing Airborne Carbon Nanotube Particles
Judy Xiong, New York University School of Medicine
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Gene Expression Profiling of Single-Walled Carbon Nanotubes: A Unique Safety
Assessment Approach
Mary Jane Cunningham, Houston Advanced Research Center
5:00 p.m. Adjourn
DAYS: Friday, October28, 2005
Plenary Session - Shenandoah A and B
8:30 a.m. Remarks
8:40 a.m. International Aspects of Nanotechnology
Celia Merzbacher, Office of Science and Technology Policy, Executive Office of the
President
9:10 a.m. NIOSH/CDC Perspective
Vladmir Murashov, Nanotechnology Research Program, National Institute for
Occupational Safety and Health/CDC
9:25 a.m. NSF Perspective
Cynthia Ekstein, Program Director, Environmental Engineering, Bioengineering &
Environment Systems Division, National Science Foundation
9:40 a.m. Grant Presentations (Continued)
Track A - Shenandoah A and B
Neuromorphic Approach to Molecular Sensing With Chemoreceptive Neuron MOS
(CuMOS) Transistors
Edwin Kan, Cornell University
A Nanocontact Sensor for Heavy Metal Ion Detection
Nongjian Tao, Arizona State University
Carbon Nanotube Self-Assembly in a VOCs Monitoring Platform
Somnath Mitra, New Jersey Institute of Technology
Development of Nanocrystalline Zeolite Materials as Environmental Catalysts
Sarah Larsen, University of Iowa
Track B - Georgetown Room
The Fate, Transport, Transformation and Toxicity of Manufactured Nanomaterials in
Drinking Water
Paul Westerhoff, Arizona State University
Microbial Impacts of Engineered Nanoparticles
Pedro Alvarez, William Marsh Rice University
Absorption and Release of Contaminants onto Engineered Nanoparticles
Mason Tomson, Rice University
10:50 a.m. Break
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11:10 a.m. Closing Remarks
11 ;45.a.m. Adjourn
1:30- 4:00 p.m. Nanoscience Building Tour at the Naval Research Laboratory in Washington, DC
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
U.S. Environmental Protection Agency
Nanotechnology and the Environment: Applications and Implications
Progress Review Workshop III
Holiday Inn Rosslyn at Key Bridge
1 SOON FortMyerDrive
Arlington, VA 22209
October 26 - 28, 2005
Participants List
Filar Aguar
European Commission
Brussels, Belgium
Pedro Alvarez
Rice University
Houston, TX
Anne Anderson
Utah State University
Logan, UT
Bahman Asgharian
CUT
Research Triangle Park, NC
Bhavik Bakshi
Ohio State University
Columbus, OH
Paul Bertsch
The University of Georgia
Aiken, SC
David H. Blakey
Health Canada
Ottawa, Ontario, Canada
Jean-Claude Bonzongo
University of Florida
Gainesville, FL 3
William Boyes
U.S. Environmental Protection Agency
Research Triangle Park, NC
Doug Britt
Dynamac Corporation
Rockville, MD
Warren Chan
University of Toronto
Toronto, Ontario Canada
Lung-Chi Chen
New York University School of Medicine
Tuxedo, NY
Yongsheng Chen
Arizona State University
Tempe, AZ
Adele Childress
Centers for Disease Control and Prevention
Atlanta, GA
Flora Chow
U.S. Environmental Protection Agency
Washington, DC
David Clarke
Inside Washington Publishers
Arlington, VA
Brian Colton
Health Canada
Ottawa, Ontario, Canada
Vicki Colvin
Rice University
Houston, TX
Mary Cooke
U.S. Environmental Protection Agency
Washington, DC
Mary Jane Cunningham
Houston Advanced Research Center
The Woodlands, TX
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop III
Ben Dawson-Andoh
West Virginia University
Morgantown, WV •
Emmanuelle Delbecque
Embassy of France in the United States
Washington, DC
Baolin Deng
University of Missouri at Columbia
Columbia, MO
Nancy Denslow
University of Florida
Gainesville, FL
Mamadou S. Diallo
California Institute of Technology
Pasadena, CA
Linh Do
University of Oklahoma
Norman, OK
Paul Dufour
Government of Canada
Ottawa, Ontario, Canada
Jeremiah Duncan
Advancing Science, Serving Society Fellow
U.S. Environmental Protection Agency
Washington, DC
Michael Eck
U.S. Army Environmental Center
Gunpowder, MD
Cynthia Ekstein
National Science Foundation
Arlington, VA
William Farland
U.S. Environmental Protection Agency
Washington, DC
Leili Fatehi
Meridian Institute
Washington, DC
Lee Ferguson
University of South Carolina
Columbia, SC
Richard Fil
Robinson & Cole, LLP
Hartford, CT
Stiven Foster
U.S. Environmental Protection Agency
Washington, DC
Bob Gawley
University of Arkansas
Fayetteville, AR
Vicki Grassian
University of Iowa
Iowa City, IA
Peter Grutter
McGill University
Montreal, Quebec, Canada
Ting Guo
University of California at Davis
Davis, CA
Soon Young Han
U.S. Environmental Protection Agency
Washington, DC
Pat Heiden
Michigan Technological University
Houghton, MI
Geoffrey M. Holdridge
National Nanotechnology Coordination Office
Arlington, VA
Patricia Holden
University of California at Santa Barbara
Santa Barbara, CA
John Honek
University of Waterloo
Waterloo, Ontario, Canada
Chin-pao Huang
University of Delaware
Newark, DE
Robert Hurt
Brown University
Providence, RI
I
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Nanotechnology and the Environment; Applications and Implications Progress Review Workshop III
Sulay Jhaveri
American Association for the Advancement of
Science - EPA Fellow
U.S. Environmental Protection Agency
Washington, DC
Vijay John
Tulane University
New Orleans, LA
Murray Johnston
University of Delaware
Newark, DE
Edwin Kan
Cornell University
Ithaca, NY
Agnes Kane
Brown University
Providence, RI
David Kargbo
U.S. Environmental Protection Agency
Philadelphia, PA
Barbara Kara
U.S. Environmental Protection Agency
Washington, DC
Jon Kaye
U.S. Environmental Protection Agency
Washington, DC
Tohren Kibbey
University of Oklahoma
Norman, OK
James Kilduff
Rensselaer Polytechnic Institute
Troy, NY
JaehongKim
Georgia Institute of Technology
Atlanta, GA
John D. Koutsandreas
Florida State University
Tallahassee, FL
Sarah Larsen
University of Iowa
Iowa City, IA
Mitch Lasat
U.S. Environmental Protection Agency
Washington, DC
Barry La vine
Oklahoma State University
Stillwater, OK
Marcia Lawson
American Chemistry Council
Arlington, VA
Stephen Lingle
U.S. Environmental Protection Agency
Washington, DC
Philip Lippel
National Nanotechnology Coordination Office
Arlington, VA
Greg Lowry
Carnegie Mellon University
Pittsburgh, PA
Yunfeng Lu
Tulane University
New Orleans, LA
Neil MacDonald
Federal Technology Watch
Arlington, VA
Kristin Marano
ENVIRON
Arlington, VA
Eric Marcotte
Canadian Institutes of Health Research
Ottawa, Ontario, Canada
Linsey Marr
Virginia Polytechnic Institute and State
University
Blacksburg, VA
Susan Masten
Michigan State University
East Lansing, MI
Andrew Maynard
Woodrow Wilson International Center for Scholars
Washington, DC
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Nanotechnologf and the Environment: Applications and Implications Progress Review Workshop III
Jacob McDonald
Lovelace Respiratory Research Institute
Albuquerque, NM
Terry Me In tyre
Government of Canada
Gatineau, Quebec, Canada
Celia Merzbacher
Executive Office of the President
Washington, DC
Manju Misra
Michigan State University
E Lansing, MI v
Somenath Mitra
New Jersey Institute of Technology
Newark, NJ
Nancy Monteiro-Riviere
North Carolina State University
Raleigh, NC
Lauren Morello
E & E Publishing, LLC
Washington, DC
Ashok Mulchandani
University of California at Riverside
Riverside, CA
Vladimir Murashov
Department of Health and Human Services
Centers for Disease Control and Prevention
Washington, DC
Jay Nadeau
McGill University
Montreal, Quebec, Canada
Madeleine Nawar
U.S. Environmental Protection Agency
Washington, DC
Patrick O'Shaughnessy
The University of Iowa
Iowa City, IA
Marti Otto
U.S. Environmental Protection Agency
Washington, DC
Larry Pearl
Pesticide & Toxic Chemical News
Washington, DC
Cheryl Pellerin
U.S. Department of State
Washington, DC
Naomi Pena
Pew Center on Global Climate Change
Arlington, VA
Kurt Pennell
Georgia Institute of Technology
Atlanta, GA
Peter Perrotta
West Virginia University
Morgantown, WV
Pat Phibbs
BNA, Inc.
Washington, DC
Robert Puls
U.S. Environmental Protection Agency
Ada, OK
David Rejeski
Woodrow Wilson International Center for Scholars
Washington, DC
Mihail Roco
National Science Foundation
Arlington, VA
Michael Royer
U.S. Environmental Protection Agency
Edison, NJ
Omowunmi Sadik
State University of New York at Binghamton
Binghamton, NY
Nora Savage
U.S. Environmental Protection Agency
Washington, DC
Teresa Savarino
The Cadmus Group, Inc.
Arlington, VA
The Office of Research and Development's National Center for Environmental Research
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Nanotechnology and the Environment: Applications and Implications Progress Review Workshop HI
Gregory A. Schuckman
University of Central Florida
Lorton, VA
Selim Senkan
University of California at Los Angeles
Los Angeles, CA
Ismat Shah
University of Delaware
Newark, DE
David Sheets
Army Environmental Policy Institute
Arlington, VA
Wei-Heng Shih
Drexel University
Philadelphia, PA
Benjamin Steinberg
National Association of Regional Councils
Washington, DC
Daniel Strongin
Temple University
Philadelphia, PA
Vivek Subramanian
University of California at Berkeley
Berkeley, CA
Nongjian Tao
Arizona State University
Tempe, AZ
Timothy Taylor
U.S. Environmental Protection Agency
Washington, DC
Christopher Theodorakis
Southern Illinois University at Edwardsville
Edwardsville, IL
Sally Tinkle
National Institute of Environmental Health
Sciences
Durham, NC
Mason Tomson
Rice University
Houston, TX
Ronald Turco
Purdue University
West Lafayette, IN
Dennis Utterback
U.S. Environmental Protection Agency
Washington, DC
John Veranth
University of Utah
Salt Lake City, UT
Bellina Veronesi
U.S. Environmental Protection Agency
Research Triangle Park, NC
Karen Waldvogel
U.S. Department of Agriculture
Washington, DC
Barb Walton
U.S. Environmental Protection Agency
Research Triangle Park, NC
Joseph Wang
Arizona State University
Tempe, AZ
Paul Westerhoff
Arizona State University
Tempe, AZ
Francoise Winnik
Universite de Montreal
Montreal, Quebec, Canada
William Winter
State University of New York
Syracuse, NY
Anuradee Witthayapanyanon
University of Oklahoma
Norman, OK
Judy Xiong
New York University School of Medicine
Tuxedo, NY
Hong Yang
University of Rochester
Rochester, NY
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Turco, R.F., 26,104
Veranth,J.,22,91
Wang, J., 16, 63,68
Weisner, M.R., 94
Westerhoff, P., 22,93
Winnik, F., 25, 99
Winter, W.T., 9,37
Witthayapanyanon, A., 9, 38
Xibng, J., 28
Yang, H., 27,105
Yost,G.S.,91
Zhang, W-x., 11,51
Zhao, D., 12, 57
Zivanoic, S., 12
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