It sounds ideal—a new technology that can improve medical treatment; provide clean, affordable energy; produce stronger, lighter materials; and offer a host of other benefits. Yet despite all the promise, no one is quite sure of the exact health and safety risks that might accompany the development of products that make use of nanotechnology.
“There are a lot of ways nanotechnology and nanomaterials can reap tremendous benefits to society,” says Kristen Kulinowski, faculty fellow in chemistry at Rice University in Houston, Texas, and director for external affairs for the university’s
Center for Biological and Environmental Nanotechnology (CBEN). At the same time, she said, “There may be some unintended consequences” to humans or the environment.
Researchers are using nanoscience to discover new behaviors and properties of materials that are unbelievably small—a nanometer is one-millionth of a meter. A sheet of paper, for example, is 100,000 nanometers thick, while an inch equals 25,400,000 nanometers.
Materials have different properties at the nanoscale, so they may be better at doing things like conducting electricity or reflecting light, according to the federal
National Nanotechnology Initiative. And because they have far larger surface areas than similar volumes of larger-scale materials, there is more surface area available for them to interact with other materials.
Nanomaterials open up new possibilitiesNanomaterials “have unique properties that allow things to happen that otherwise wouldn’t,” says David Eaton, associate vice provost for research and director of the
Center for Ecogenetics & Environmental Health at the University of Washington in Seattle. Eaton chaired a committee of the National Research Council that reviewed the
National Nanotechnology Initiative’s Strategy for Nanotechnology-Related Environmental, Health and Safety Research.
While in some instances nanotechnology involves “taking something and making very modest improvements,” Eaton says, “some things are completely revolutionary. They couldn’t do it any other way.” But those revolutionary properties could cause problems in their own right, because no one is certain of the impact nanomaterials might have on human health or environmental safety.
“Nanoparticles might not necessarily behave in the same way as their non-nano analogs do,” says Kulinowski, who is also director of the
International Council on Nanotechnology (ICON). “We can’t assume [nanoparticles] will behave in the same way in living organisms or the natural environment.”
In some cases nanomaterials are already used in cosmetics, such as anti-aging products, or to make better, stronger baseball bats. In other cases they are used to enhance drug delivery or improve energy technology. And their potential seems virtually endless.
For example, at Rice, researchers have developed nanoshells coated in gold. The nanoshells scatter light, which is used to detect cancer cells. Then the light is converted to heat, destroying the cancerous cells. Human trials are now underway. Discoveries such as these are “poised to have a major impact on the way cancer is attacked,” Kulinowski says.
Rice also is involved in a pilot program underway in Mexico, where nanorust—minute bits of iron oxide—are being used to remove arsenic from water contaminated by mining. Nanorust naturally binds with arsenic, and then nanomagnetics keep the poison trapped in a filter.
At Wake Forest University, researchers at the
Center for Nanotechnology and Molecular Materials are working closely with university physicians to develop tools that will help them treat patients. For example, nanotechnology can be used to sense a disease, and then drug-carrying nanoparticles can be injected into the bloodstream to treat it, eliminating surgery and reducing the risk for infection, says David Carroll, the nanotechnology center’s director
The technology also has a major role to play as medicine becomes more personalized. Using nanotechnology “dramatically lowers the cost of being personal for each of your patients,” Carroll says. A wide range of clinical trials are taking place around the globe, exploring the use of nanotechnology to treat everything from cancer to myocardial infarction to drug addiction.
Wake Forest is also focusing its efforts on energy-saving devices and has even launched two companies based on its breakthroughs. One, PlexiLight, uses nanotechnology to produce light— rather than using a byproduct that comes from heating a filament or gas—making it extremely energy efficient. If developed as a substitute for fluorescent lighting, it would require no bulbs and would not emit heat, which requires energy use to cool.
While some products using nanotechnology area already on the market—non-stick pans for cooking, golf clubs, and even children’s stuffed animals designed to ward off bacteria and mold—many others are still in the developmental stage.
Eaton calls using nanotechnology-based composite materials to produce new golf clubs “mundane.” Using such materials to produce a stronger, lighter airplane, he says, “has huge applicability,” because it would require much less fuel.
Uncertainties aboundBut many companies have been treading lightly when it comes to entering the nanotechnology arena, Eaton says. While he thinks most nanomaterials won’t pose a problem, “there are a lot of applications in which industry is proceeding cautiously and is concerned about potential health effects.” An aircraft manufacturer may have concerns about liability issues and asbestos-like, long-term health effects of exposure to nanomaterials—if a machinist drills a hole in a plane containing nanomaterials, for example.
In a recent study, published in the
Journal of Molecular Cell Biology, Chinese researchers found that certain nanoparticles being developed for use in medicine can cause lung damage by triggering programmed cell death. Researchers hope to find ways to prevent that from occurring.
Kulinowski knows of one case where wound dressings containing nanosilver, which has great antimicrobial properties, were used on a burn victim to prevent the growth of bacteria and fungi. The patient had resulting elevated levels of silver in his blood that caused toxicity in the liver, but when the dressings were removed the silver levels dissipated.
Researchers have also seen that nanosilver has affected shellfish in San Francisco Bay by interfering with their reproduction, Carroll says. At his lab in North Carolina, the building is designed so no nanomaterials are released into the environment.
Experts try to assess risksEfforts on gauging potential effects run the gamut from a group of university researchers studying the health and safety impacts of nanomaterials, to a regional health and safety forum bringing together industry and universities, to an online wiki about the safe handling of nanomaterials.
Jim Hutchison, a chemistry professor at the University of Oregon and director of the
Safer Nanomaterials and Nanomanufacturing Initiative, says, “Nanotechnology may not have any more specific hazards than any other chemical class,” but it comes under scrutiny because it is such a new field. “In some sense, we are just exiting the pioneering phase of nanotechnology.”
Part of the problem, Hutchison says, is that it is not easy or inexpensive to test the safety of nanomaterials—extensive studies are needed, and few are willing to invest the money, because no one is quite sure which products will be commercially viable.
Another issue, says David Barber, associate professor of toxicology at the University of Florida in Gainesville, is that simply testing the materials is a challenge. Testing is designed for dissolved chemicals, so researchers are left trying to determine what size dose of nanomaterials they will be testing, and whether the materials will be measured by mass, surface area, or number of particles.
While nanomaterials are comprised of chemicals that scientists are familiar with in their soluble form, they aren’t sure what they might have to do differently with materials in their new form, Barber says.
As an outgrowth of those concerns, engineers, biologists, and chemists at UF began working together about five years ago as the UF Nanotoxicology Group, studying the health and safety impacts of nanomaterials and trying to determine what happens to the particle in the human body or when released into the water or soil. “Does it do something different than a chemical would if dissolved?” says Barber, who believes that kind of combined knowledge and expertise is needed to effectively study the materials’ safety.
Barber’s effort focuses on metals such as aluminum, copper, silver, and nickel. To date, she says, nothing is “shown to be dramatically different than other forms of the same chemical.”
Other universities and organizations also are working to try to determine the materials’ safety. This summer, private industry and several universities in the Northwest are hostied the
Nanotechnology Health and Safety Forum. Hutchison, who is an expert in the field of green chemistry, spoke about the future of nanotechnology. He would like to see more green practices incorporated into nanotechnology, while the science is still in its formative stages.
In another effort to address safety concerns, the
International Council on Nanotechnology (ICON), headed by Kulinowski, in June unveiled the
GoodNanoGuide, an online wiki about the safe handling of nanomaterials. Aimed at those who work with the materials, the
GoodNanoGuide pulls together journal articles and information on safe handling of nanomaterials from sources around the globe.
So far, no studies have shown that any individuals have been harmed by exposure to nanomaterials, she says.
Kulinowski says “the latest bottom line on whether nanomaterials pose a risk to human health: It depends.” Factors are many, including the dose of the nanomaterial, the biopersistence (how quickly a body can clear them), and the surface, since it appears those with coatings or molecular fragments attached to the outer wall might be less toxic.
Another issue is what happens to the materials at the end of the product life cycle. “There’s a whole host of questions still outstanding there,” Kulinowski says.
ICON is now in the process of collecting information on best safety practices for people working with nanomaterials. Those who work with the materials have a higher probability of being exposed to higher levels of the material for longer periods of time than consumers.
And many questions surround the disposal of the materials, Kulinowski says, including whether existing technology can prevent them from leaching from landfills, whether wastewater treatment plants can handle those that end up in wastewater, and what is the likelihood of nanomatierals being released from products.
Research, caution, and prudence are needed as the field progresses, she says, as scientists try to “make sure we get the effects we want without the effects we don’t want.”
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