Are Nanomaterials Safe?

Brown team asks big questions about tiny technology

by Wendy Y. Lawton

Nanomaterials are the stuff of the future. Inventors hope to use these atomic-scale tubes, fibers, spheres, crystals, and films to make faster cars and planes, more powerful computers and satellites, better microchips and batteries. There are even plans to use these materials - 1,000 times thinner than human hair - to make artificial muscle, military armor, even medicines.

Nanomaterials are also the stuff of today. They can be found in sunscreens, concrete, tennis rackets, car bumpers, even stain-resistant khakis. But are they safe?

A team of Brown researchers will come up with answers. With a new four-year, $1.8-million National Science Foundation grant, the group will create and test a variety of materials to see how they interact with human and animal cells. The aim: Find out which sizes, shapes, compounds, and coatings damage or kill cells. Such information can be used to manufacture nontoxic types.

The project puts Brown at the forefront of environmental health science. Only a few universities in the United States conduct research in nanotoxicology, an increasingly hot scientific topic. Although nearly 4,000 nanotechnology patents have been issued and the federal government invests nearly $1 billion in the field each year, very little is known about how nanoparticles affect human health.

Engineering Professor Robert Hurt, the lead investigator on the project, said the team's results won't halt nanotech. Made of a variety of materials, such as carbon and silicon, these tiny bits of matter pack desirable properties such as extreme strength and outstanding electrical or thermal conductivity, making them an ideal resource for the aerospace, electronics, automotive, and telecommunications industries.

"The question isn't whether nanomaterials are good or bad," Hurt said. "The question is which are toxic? Under what conditions? And can we make and purify them in different ways to avoid toxicity - to make 'green' nanomaterials?"

The nanotech team hails from all corners of campus.

Along with Associate Professor of Engineering Greg Crawford, Hurt will crank out carbon nanotubes, fibers, and spheres - all popular in electronics - by the billions. Crawford will arrange the materials on glass slides based on size, shape, and chemical composition - a novel "chip" platform that will allow for precise, systematic testing.

The chips will then head to Associate Professor of Medical Science Jeff Morgan and Professor of Medical Science Agnes Kane.

Morgan, a biologist and tissue engineer, will test the materials' effect on lab-grown human skin cells. Kane, a pathologist, will test the materials on macrophages, cells that defend against foreign invaders, culled from mice. Both will check to see if cells die, incur DNA damage or trigger exaggerated immune defenses.

A handful of studies show that some nanomaterials are toxic. Last month, Kane and Hurt presented results of their preliminary research, which shows that carbon nanotubes treated with iron kill protective macrophages isolated from mice.

For years, Kane has studied the toxic effects of asbestos. These fibers share some qualities with commercial-grade carbon nanotubes: They're long and thin and tiny, allowing them to burrow deep inside lung tissue. Asbestos and nanotubes can both contain iron - which Kane believes could be the culprit that makes both particles dangerous to humans.

"If we could figure out the rules that govern nanotube toxicity," Kane says, "we can engineer the toxicity out."

The nanotech project doesn't end in the lab.

Sociology Professor Phil Brown will explore the social and ethical implications of nanotechnology and how to communicate health exposure risks to the public. Brown will survey faculty and students who work with nanomaterials to better understand how they handle them in the lab and what they know about the potential risks involved in their work. His findings will have a direct impact on campus: Brown will work with the University's Department of Environmental Health and Safety to develop safety guidelines and educational materials for lab staff.

"Technologies that seem beneficial at first can turn out to be harmful, a lesson history shows with pesticides like DDT and drugs like thalidomide," Brown said. "The vision here is to start asking questions about health and environmental consequences before a technology becomes widespread. It is in everyone's interest to be safe."