|The New Atomic Scientists|
The next industrial revolution may be closer than you think. At its heart are objects only recently invented, yet invisible to the unassisted eye. As small as ten hydrogen atoms in diameter, they are a thousand times thinner than human hair. A million of them would fit on the head of a pin. They are in your L.L. Bean chinos, in the shafts of your golf clubs, in your sunscreen, your air sanitizers, your makeup, your cultured diamonds. They are in almost 300 consumer products worth more than $30 billion. Because they are unusually strong, permeable, and conductive, scientists believe these materials might one day generate clean energy, attack tumors in the body, clean up toxic spills, and slow the spoilage of food. More than $10 billion a year is already being spent around the world to invent more of them.Welcome to the world of nanomaterials, a catchall phrase that includes a wide range of tiny, man-made clusters of atoms and molecules. Their existence is a result of the newfound ability of scientists to manipulate matter at the atomic level. “Every era has its exciting developments,” says engineering professor and nanotechnology researcher Robert Hurt. “It used to be the space race. Now it’s nanotechnology.”
Of course, industrial history is replete with promising substances that later turned out to be deadly rather than miraculous. Before it was found to cause pulmonary disease, asbestos, for example, was once considered an ideal material for clothing, buildings, and even toys; today it kills 10,000 people every year in the United States alone. Millions of pregnant women took DES, a synthetic estrogen, until it was linked to a rare cancer in female offspring. Chlorofluorocarbons, the chemical compounds implicated in the hole in the ozone layer, were at one time in every spray can on the supermarket shelf. Children used to play with mercury. And the list goes on.
Hurt is one of a growing number of researchers who are asking: are nanomaterials safe? Could they be the next miracle substance that turned out to be a killer? Already there are ominous signs. According to “Nanotechnology: A Research Strategy for Addressing Risk,” a policy paper written by Andrew Maynard, the chief science adviser for the Project on Emerging Nanotechnologies at the Woodrow Wilson International Center for Scholars, “carbon nanotubes can cause lung inflammation and granulomas in animals, and some nanoparticles seem to be more harmful mass-to-mass than their larger counterparts. Certain applications of nanotechnology will present risks unlike any we have encountered before.”
Robert Hurt is hoping to reduce these risks. Along with Professor of Medical Science Agnes Kane, he leads a multidisciplinary project that places Brown among a handful of universities looking at the wider implications of nanotechnology breakthroughs. Armed with a four-year, $1.8 million grant from the National Science Foundation, Hurt and Greg Crawford, an associate professor of engineering, are manufacturing a variety of nanomaterials that are then tested on lab-grown human skin cells by Kane and Jeff Morgan, a tissue engineer and an associate professor of medical science. Hurt and Kane are particularly interested in a nanomaterial that, if injected into the body, could deliver a cancer-fighting drug to a tumor. “There’s great potential,” Hurt says, “to use nanomaterials in the body.” The goal of the project, he says, is not to declare all nanomaterials dangerous or safe, but to determine which are toxic and why. Their work could guide the industry toward engineering the toxicity out of the materials, in effect creating a safe and green nanotechnology.
The project doesn’t stop there, however. Also on the team is sociology professor Phil Brown, who is studying the social and ethical implications of nanotechnology. His work will also focus on how best to communicate the exposure risks to the public—including the faculty and students who handle them as part of their research. “Most nanomaterials are still in the lab,” Hurt explains, making it the ideal time to assess their risks.
The concern over nanomaterial safety began in 1998, when a news item by Robert F. Service in Science noted that the properties of nanotubes closely resemble those of asbestos. One researcher noted in the article that “nanotubes are the right size to be inhaled, their chemical stability means that they are unlikely to be broken down quickly by cells and so could persist in the body, and their needlelike shape could damage tissue.”
Since then, Agnes Kane, a pathologist whose research has long focused on asbestos, has found more and more to be worried about. She says carbon nanomaterials share with asbestos fibers some disturbing chemical and structural traits. Both are small, lightweight fibers that cannot dissolve in the body. Both can become airborne and penetrate the lungs. Can carbon nanomaterials, Kane wonders, behave in the lungs like asbestos fibers, which are known to cause a type of lung cancer? What happens when nanomaterials are absorbed in the skin? And what damage could they do in a water supply or a landfill?
The Brown team ponders these questions first by generating nanomaterials in the lab. Hurt and Crawford use commercially available carbon to engineer billions of nanotubes, spheres, and fibers. Next, Crawford arranges them on glass slides in ascending order by size and concentration. Each one-by-two-inch slide contains 1,000 square pads. Each pad holds up to a million nanomaterials.
In addition to size and concentration, Crawford arranges the material by such traits as shape, impurity, and position, making it possible to pinpoint whether and how the material might become toxic. “These things all seem to make a difference in toxicity,” Hurt says. Next, Jeffrey Morgan tests the chips to see which nanomaterials cause damage to the lab-grown skin cells. Kane, meanwhile, tests the chips on macrophages, which are white blood cells that attack disease in mice. “Maybe nothing is toxic in the end,” Crawford says, noting that their work is still in its infancy.
He and Hurt have made well over a hundred chips so far, which Kane and Morgan continue to test. The first published results will likely concern iron residue that accumulates inside carbon nanotubes. The team is testing the residue to see whether it can create free radicals, which are unstable molecules in the body that can damage cells and tissues and contribute to illness. Kane says the iron in asbestos has been shown to create free radicals.
Hurt and a team of engineers are also experimenting with another form of nanomaterials based on liquid crystal, which produces a new, especially promising carbon nanomaterial that is spherical. When magnified, the spheres look like beach balls or beads of tapioca. They are inexpensive to produce and contain no potentially toxic iron or other metal impurities. What’s most important, though—and what illustrates the immense promise nanomaterials hold—is that Hurt and his team have found that the spheres have a high enough surface area to carry tiny but strong doses of medicine—for instance, a cancer-fighting drug. Kane’s research has shown that the spheres can penetrate deeply into the mesothial cells that line the lungs, leading her to believe that they could be loaded up with medicine and implanted in the lungs in order to reach and destroy meso-theliomas, or tumors linked with asbestos. The results of this part of the team’s study will appear in a forthcoming article in the journal Advanced Materials.
If nanomaterials turn out to have destructive health effects, what will it mean for the scientists and students who have been already been handling them in much larger quantities than your average consumer encounters in everyday products? The University is taking no chances—or at least as few as the current state of knowledge allows.
A hundred years ago, when the chemist Marie Curie was researching radioactive material, she would hold it in her bare hands. “With radioactivity work in the early days,” says Stephen Morin, Brown’s director of environmental health and safety, “the exposure limits and regulations came about after people were injured. Science has come a long way since then.” As part of the Hurt-Kane project, the team will work with Morin and his staff to develop safety rules that are specific to nanotechnology.
Daniel Sarachick, the chemical hygiene officer in Morin’s office, estimates that about thirty Brown professors conduct lab work that involves the use of nanomaterials. As the nanotechnology industry grows, that number is likely to rise significantly. Right now those scientists follow the University’s existing rules for chemical hygiene, which require things like frequent hand washing and the use of protective clothing. The policy also mandates that scientists conduct research under the protection of a hood mechanism that sucks away and exhausts all fumes. A problem with nanomaterials, Morin says, is their size: the air turbulence of a fume hood can disturb them enough to interfere with the research. That’s why Sarachick would like to see researchers use a respirator.
“We don’t know what the effects are,” says Phil Brown. “So we have to be cautious and proactive.” Brown’s work focuses in part on trying to find a sensible way to regulate nanomaterials safety. Alcohol and bug sprays come with warning labels, he points out, but what would you say on a warning label for a product containing a nanomaterial? He is surveying Brown scientists and graduate students who work with these materials to get their sense of what safety regulations should be in place and who should be in charge of enforcing them, whether it be the U.S. Environmental Protection Agency, the U.S. Food and Drug Administration, or some other bureaucracy. He hopes eventually to extend his survey to include scientists at other universities. (Brown is also studying the ethical implications of nanotechnology, including the question of how much money society should devote to a field that at first will likely benefit only a small number of wealthy countries.)
Brown himself is firmly in the better-safe-than-sorry camp. He leans toward agreeing with the several European countries that have aggressively regulated the industry. A few groups have called for an immediate halt to nanotech research, but that is unlikely to happen. “I don’t think we can or should shut down the whole research enterprise,” Brown says.
Kane agrees it would be unwise to shut down the development and manufacturing of nanomaterials. Instead, she argues, there should be an ongoing discussion and application of safety precautions. She believes, for example, that cosmetics that use nanomaterials should say so on the label so that consumers can make a choice about whether or not to buy them.
The Woodrow Wilson Center’s Project on Emerging Nanotechnologies, which is supported by the Pew Charitable Trusts, is an attempt to bring the public into the world of nanotechnology. “Our goal,” the project’s mission statement explains, “is to inform the debate and to create an active public and policy dialogue. [The project] is not an advocate either for, or against, particular nanotechnologies. We seek to ensure that as these technologies are developed, potential human health and environmental risks are anticipated, properly understood, and effectively managed.” In July Andrew Maynard called for more government spending for nanotechnology safety testing. Right now, the U.S. government spends $1 billion a year on nanotechnology research and development, of which, according to the center, only $11 million is devoted to researching the risks.
David Rejeski, director of the project, has worked with his staff to create a database of nearly 300 consumer products that contain nanomaterials. The list, which can be found at www.nanotech project.org, includes such various items as Behr Premium Plus Kitchen and Bath Paint, Dockers Go Khaki slacks, Blue Lizard Baby sunblock, and Bionova Cosmetics by Barneys New York.
Of course, 300 products are not very many. Kane and Hurt are eager to come up with conclusive toxicity results before the list is in the thousands or millions. At this early stage, Kane points out, there is communication and cooperation among researchers, industry, and regulatory agencies. Once patents and other legal matters get in the way, that cooperation could evaporate. For decades, Kane says, legal issues got in the way of unbiased asbestos research. She doesn’t want that to happen again. The window of opportunity, Hurt says, is open now.
Former BAM senior writer Emily Gold Boutilier is the editor of Amherst Magazine.