What are nanomaterials?
Scientists have not unanimously settled on a precise definition of nanomaterials, but agree that they are partially characterized by their tiny size, measured in nanometers. A nanometer is one millionth of a millimeter - approximately 100,000 times smaller than the diameter of a human hair.
Nano-sized particles exist in nature and can be created from a variety of products, such as carbon or minerals like silver, but nanomaterials by definition must have at least one dimension that is less than approximately 100 nanometers. Most nanoscale materials are too small to be seen with the naked eye and even with conventional lab microscopes.
Materials engineered to such a small scale are often referred to as engineered nanomaterials (ENMs), which can take on unique optical, magnetic, electrical, and other properties. These emergent properties have the potential for great impacts in electronics, medicine, and other fields. For example,
- Nanotechnology can be used to design pharmaceuticals that can target specific organs or cells in the body such as cancer cells, and enhance the effectiveness of therapy.
- Nanomaterials can also be added to cement, cloth and other materials to make them stronger and yet lighter.
- Their size makes them extremely useful in electronics, and they can also be used in environmental remediation or clean-up to bind with and neutralize toxins.
However, while engineered nanomaterials provide great benefits, we know very little about the potential effects on human health and the environment. Even well-known materials, such as silver for example, may pose a hazard when engineered to nano size.
Nano-sized particles can enter the human body through inhalation and ingestion and through the skin. Fibrous nanomaterials made of carbon have been shown to induce inflammation in the lungs in ways that are similar to Asbestos .
Where are nanomaterials found?
Some nanomaterials can occur naturally, such as blood borne proteins essential for life and lipids found in the blood and body fat. Scientists, however, are particularly interested in engineered nanomaterials (ENMs), which are designed for use in many commercial materials, devices and structures. Already, thousands of common products-- including sunscreens, cosmetics, sporting goods, stain-resistant clothing, tires, and electronics—are manufactured using ENMs. They are also in medical diagnosis, imaging and drug delivery and in environmental remediation.
What are some of the main take-home points that NIEHS and NTP want people to know about nonmaterials?
There are three main take-home points:
- There is no single type of nanomaterial. Nanoscale materials can in theory be engineered from minerals and nearly any chemical substance, and they can differ with respect to composition, primary particle size, shape, surface coatings and strength of particle bonds. A few of the many examples include nanocrystals, which are composed of a quantum dot surrounded by semiconductor materials, nano-scale silver, dendrimers, which are repetitively branched molecules, and fullerenes, which are carbon molecules in the form of a hollow sphere, ellipsoid or tube.
- The small size makes the material both promising and challenging. To researchers, nanomaterials are often seen as a "two-edged sword." The properties that make nanomaterials potentially beneficial in product development and drug delivery, such as their size, shape, high reactivity and other unique characteristics, are the same properties that cause concern about the nature of their interaction with biological systems and potential effects in the environment. For example, nanotechnology can enable sensors to detect very small amounts of chemical vapors, yet often there are no means to detect levels of nanoparticles in the air—a particular concern in workplaces where nanomaterials are being used.
- Research focused on the potential health effects of manufactured nano-scale materials is being developed, but much is not known yet. NIEHS is committed to developing novel applications within the environmental health sciences, while also investigating the potential risks of these materials to human health.
Why is NIEHS involved in nanotechnology?
NIEHS has two primary interests in the field of nanotechnology: harnessing the power of engineered nanomaterials to improve public health, while at the same time understanding the potential risks associated with exposure to the materials.
What is NIEHS Doing?
Currently, very little is known about nanoscale materials and how they affect human health and the environment. NIEHS is committed to supporting the development of nanotechnologies that can be used to improve products and solve global problems in areas such as energy, water, medicine and environmental remediation, while also investigating the potential risks these materials pose to human health and the environment. NIEHS researchers are committed to prevention through design, a phrase which embodies the effort to avoid any potential hazards in the production, use, or disposal of nanoscale products and devices by anticipating them in advance.
NIEHS has developed an integrated, strategic research program that includes grantee support, utilizing our in house research expertise, investing in the development of nano-based applications that benefit the environment and public health, and tapping into the world class toxicity testing capabilities of the National Toxicology Program (NTP), to understand the impacts of engineered nanomaterials on human health, and to support the goals of the National Nanotechnology Initiative .
One of the key ways NIEHS is supporting research on the health impacts of engineered nanomaterials is through NIEHS Centers for Nanotechnology Health Implications Research (NCNHIR) consortium. The NCNHIR is an interdisciplinary program consisting of eight Cooperative Centers and other active grantees. Established in 2010, consortium researchers are working to understand how engineered nanomaterials interact with biological systems and how these effects may impact human health.
NIEHS also established contractual agreements for nanomaterial characterization and an informational database to support this consortium. The overarching goals of these efforts are to gain fundamental understandings on the interactions of ENMs with biological systems to better understand potential health risks associated with ENM exposure. These findings will also guide safe development and use of nanotechnology.
The consortium grew out of work that began by grantees supported through the Engineered Nanomaterials Grand Opportunity (Nano GO) grant program funded through the American Recovery and Reinvestment Act. The NCNHIR consortium continues to build upon the research protocols and lessons learned through Nano GO.
Additionally, NIEHS has formed partnerships with other federal agencies to support grantees across the country as part of its Environmental Health and Safety program. For example, NIEHS has joined with the Environmental Protection Agency (EPA), National Science Foundation (NSF), National Institute for Occupational Safety and Health (NIOSH) and other NIH institutes and centers (ICs) over the years to support research strategies addressing environmental health and safety aspects of engineered materials.
Visit NIEHS Nano Environmental Health and Safety (Nano EHS) website for additional information on NIEHS' involvement in the field of nanotechnology.
Visit the "Who We Fund" website for a complete list of NIEHS-supported grants. The “Who We Fund: Application of Technology to Disease – Nanotechnology” list identifies NIEHS grantees working on nanotechnology.
NIH Research Portfolio Online Reporting Tools (REPORT) provides access to reports, data, and analysis of NIH research activities.
NIH Funding Opportunities and Notices are online.
Can you provide examples of the type of work NIEHS has funded?
NIEHS researchers have produced hundreds of papers advancing our knowledge of nanomaterials and their potential impact on the environment. A small sampling demonstrates the depth and breadth of the work:
- Researchers were concerned about whether inhaled carbon nanotubes could lead to certain lung diseases, including pleural fibrosis, which results in the hardening and thickening of the tissue which covers the lungs, impairing breathing. Testing this hypothesis, they exposed laboratory mice to varied doses of pollutants and nanoparticles. Mice exposed to certain doses of carbon nanotubes developed subplural fibrosis just two to six weeks after inhaling carbon nanotubes. The work suggests that minimizing inhalation of nanotubes is prudent until further long-term assessments are conducted.[i]
- Low concentrations of carbon nanoparticles had profound effects on cells lining renal tubules—a critical structure in the kidneys. Both barrier cell function and protein expression were impacted. The results indicate that carbon nanoparticles impact renal cells at concentrations lower than previously known and suggest caution with regard to increasing carbon nanoparticles levels entering the food chain.[ii]
- Nanoscale materials are being used in many cosmetics, sunscreen and other consumer products. Possible absorption of the materials through the skin, and potential consequences, have not been determined. NIEHS-funded scientists applied nanosized particles of Cadmium selenide, a known Carcinogen , on hairless laboratory mice. They found that when the mice’s skin had been abraded to remover upper skin layers before the solution was applied, cadmium elevation was detected in the mice’s lymph nodes and liver. When the quantum dots of cadmium selenide were applied to the undisturbed skin of mice, no consistent cadmium elevation was detected in the organs. The study concluded that skin absorption of nanomaterials depended on the quality of the skin barrier and that future risk assessments should consider key barrier aspects of skin and its overall integrity.[iii]
- Nanosized materials show great promise in drug delivery, with the potential of targeting cancerous cells with a drug but avoiding an attack on healthy cells. One NIEHS-funded study demonstrated that the ability of two lines of cancer cells to absorb nanosized, rod-shaped particles differed depending on the aspect ratio of the nanoparticles—meaning the proportions between the particles’ height and width. The finding could help in achieving more efficient drug delivery.[iv]
[i] Ryman-Rasmussen JP, MF Cesta, AR Brody, JK Shipley-Phillips, JI Everitt, EW Tewskbury, OR Moss, BA Wong, DE Dodd, ME Anderson JC Bonner. Inhaled carbon nanotubes reach the subplural tissue in mice. Nature Nanotechnology (2009) v. 4 (11): 747-51. Abstract[ii] Blazer-Yost BL, A Banga, A Amos, E Chernoff , X Lai, C Li, S Mitra, FA Witzmann. Effect of carbon nanoparticles on renal epithelial cell structure, barrier function and protein expression. Nanotoxicology (2011) v.5 (3):354-71. Abstract[iii] Gopee, N, D Roberts, P Webb, C Cozart, P Siitonen, J Latendresse, A Warbitton A, W Yu, V Colvin, N Walker, P Howard. Quantitative Determination of Skin Penetration of PEG-Coated CdSe Quantum Dot in Dermadraded but not Intact SKH-1 Hairless Mouse Skin. Toxicological Sciences (2009) v. 111(1):37-48. Abstract
What is NIEHS doing to advance the development and application of nanomaterials to be used in environmental health research?
Much of NIEHS’s efforts are focused on the potential toxicity of engineered materials. However, NIEHS has developed a nanotechnology application program mostly through Cadmium efforts, including multi-institute bioengineering research opportunities, the NIH Genes, Environment and Health Initiative, and the Small Business Program (SBIR). NIEHS-funded grantees are working to develop nanotechnology-based sensors to detect exposure to toxic pollutants that will help increase our understanding of the biological consequences of exposure, and developing strategies to reduce the toxicity of environmental factors. Several investigator-initiated grants are being supported.
Specifically, how is the Superfund Research Program involved in nanotechnology-related issues?
The Superfund Research Program is supporting grantees that are developing new or improved technologies and methods, including the promising field of nanotechnology, to help monitor and remediate, or clean up, around Superfund sites. Nanomaterials offer some distinct advantages to remediation technologies such as large surface-area-to-volume ratio and high chemical reactivity. Superfund researchers are also looking at how nanomaterials behave in the environment as they are used for remediation.
For more information specifically related to nanotechnology, visit the SRP Search webpage and enter the search term "nano*",The SRP is a network of university grants that are designed to seek solutions to the complex health and environmental issues associated with the nation's hazardous waste sites. The research conducted by the SRP is a coordinated effort with the Environmental Protection Agency, which is the federal entity charged with cleaning up the worst hazardous waste sites in the country.
The SRP also collaborates with other agencies to conduct interactive web-based "Risk e Learning" seminars that provide information about innovative treatment and website characterization technologies to the hazardous waste remediation community. Visit the Nanotechnology - Applications and Implications for Superfund webpage for a list of some of the seminars related to nanotechnology.
What is the National Toxicology Program (NTP) doing to assess the health risks associated with nanotechnology?
The National Toxicology Program is engaged in a broad-based research program to address the potential human health hazards associated with the manufacture and use of nanomaterials.
Scientists at the three core agencies that comprise NTP - NIEHS, National Center for Toxicological Research at the U.S. Food and Drug Administration, and National Institute for Occupational Safety and Health of the Centers for Disease Control and Prevention - have been working to evaluate the toxicological properties of a representative cross-section of several different classes of nanoscale materials. Key parameters of greatest concern relative to their potential toxicity are size, shape, surface chemistry and composition. Researchers are using studies in laboratory animals and cells, as well as mathematical models to evaluate and predict where these materials go in the body, and what potential health effects they may cause.
Cross-Agency Nanotechnology Initiatives
What cross-agency initiatives is NIEHS involved in?
NIEHS is involved in the following cross-agency initiatives:
- The National Nanotechnology Initiative (NNI), a federal, multi-agency program dedicated to expediting world class nanotechnology research and development, to foster the transfer of new technology for commercial and public benefits, to develop and sustain a skilled workforce and to support responsible development of nanotechnology.
- The Nanoscale Science, Engineering and Technology (NSET) subcommittee of NNI has four working groups that coordinate the planning, budget, program implementation and review of the nanotechnology initiative.
- The Nanotechnology Environmental and Health Implications (NEHI) subcommittee is a working group that supports Federal activities focused on the health and safety implications of nanotechnologies.
- NIEHS partnered with two other NIH institutes, the National Institute of Biomedical Imaging and Bioengineering (NIBIB) and the National Cancer Institute (NCI) to develop the NanoRegistry . The registry provides a central repository for published findings related to nanotechnology.
- Developed an interagency agreement with NCI’s Nanotechnology Characterization Laboratory to provide NIEHS grantees common engineered nanomaterials (ENMs) and to characterize the physical and chemical properties of the. This allows the grantees to have standardized characterization of the materials they are using so they can more easily compare results across studies.
- The NIH Nanomedicine Initiative is a cross-institute effort to understand and develop nanoscale technologies that could be applied to treating disease and repairing damaged tissue.
- The NIH Nano Task Force , coordinated by NIEHS represents the interests of institutes and centers within NIH who are working with nanomaterials to understand medical uses and to assess safety and Toxicology associated with these materials.
Are nanomaterials regulated?
NIEHS is not a regulatory agency and, therefore, does not enforce statutes associated with nanomaterials or other hazardous substances. For regulatory questions, or information on what other federal agencies are doing regarding nanotechnology, please visit the appropriate agency. An abbreviated listing is provided below.
- The U.S. Food and Drug Administration (FDA) regulates a wide range of products, including foods, cosmetics, drugs, devices, and veterinary products, some of which may utilize nanotechnology or contain nanomaterials.
- At the U.S. Environmental Protection Agency (EPA) , many nanomaterials are regarded as "chemical substances" under the Toxic Substances Control Act (TSCA).
- The U.S. Consumer Product Safety Commission (CPSC) is an independent federal regulatory agency that was created in 1972 by Congress in the Consumer Product Safety Act. In that law, Congress directed the CPSC to "protect the public against unreasonable risks of injuries and deaths associated with consumer products."
- ONE Nano: NIEHS's Strategic Initiative on the Health and Safety Effects of Engineered Nanomaterials - As part of its role in supporting the National Nanotechnology Initiative, the National Institute of Environmental Health Sciences (NIEHS) has developed an integrated, strategic research program—“ONE Nano”—to increase our fundamental understanding of how ENMs interact with living systems, to develop predictive models for quantifying ENM exposure and assessing ENM health impacts, and to guide the design of second-generation ENMs to minimize adverse health effects.
- Nanotechnology - Information from the Occupational Safety and Health Administration, part of the US Department of Labor.
- Nanotechnology (NIOSH) - Information from The National Institute for Occupational Safety and Health (NIOSH), part of the CDC.
- Nanotechnology Programs at FDA - Nanotechnology allows scientists to create, explore, and manipulate materials measured in nanometers (billionths of a meter). Such materials can have chemical, physical, and biological properties that differ from those of their larger counterparts.
- National Nanotechnology Initiative - Official website of the United States National Nanotechnology Initiative.
- Research on Nanomaterials - EPA scientists research the most prevalent nanomaterials that may have human and environmental health implications.
- Nanomaterial Registry - The Nanomaterial Registry compiles data from multiple databases into a single resource.
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