Measuring the Risks of Nanotechnology

Vicki Colvin

Technology Review: Questions about the safety of nanotechnology suddenly seem to be everywhere, from Michael Crichton’s bestselling novel Prey to calls for a moratorium on the technology by at least one environmental group. What are the chief concerns?

Vicki Colvin: Nanomaterials are different. Because of their small size, we are able to get them into parts of the body where typical inorganic materials can’t go because they’re too big. There is an enormous advantage to using nanoparticles if you’re engineering, for example, drug delivery systems or cancer therapeutics. This would suggest that nanomaterials that are unintentionally introduced into the body may also undergo similar processes. The concern-or the hypothesis would be a better way to say it-is that nanomaterials differ in their reactivity and biological availability. You can’t help but ask, Well, if they are powerful biological actors, then what about unintentional consequences?

TR:Are the dangers of nanomaterials well understood?
Colvin: It’s not as if no one has ever thought about how particulate matter generally can interact with organisms. We can learn a lot from particle toxicologists who characterize the effects of aerosolized particles of all sizes on health, as well as from bioengineers who consider the effects of larger particulates generated by implants wearing down in the body. Still, specific information on the health impacts of very small, nanoengineered particles under 20 nanometers is hard to come by. So the one thing everybody agrees on is that there just is not a lot of information out there.

Getting that information isn’t going to be a simple task. Nanomaterials are incredibly diverse. You can have nanoscale carbon, nanoscale Teflon, nanoscale you name it. Within that huge diversity of materials, it would be almost amazing if all those materials were as safe as water. The toxicology data is going to start to come out, and it is almost certain that it’s not going to be: nanomaterials are totally safe. Nothing in the world is totally safe.

TR:So do you expect bad news on the health effects of nanomaterials?
Colvin: I would fully expect that within the next year there will be some concrete data on health effects. Not surprisingly, there will be some news that, hey, you can’t use these materials in any possible application; you have to consider human exposure and environmental-impact issues.

From a strictly scientific perspective, there are some fascinating questions about how does the body deal with inorganic materials that are on the order of the size of hemoglobin. At this point, I think it is a mistake for someone to say nanoparticles are safe, and it is a mistake to say nanoparticles are dangerous. They are probably going to be somewhere in the middle. And it will depend very much on the specifics. But what is important is that if you’re starting an industry in the area, with billions of dollars going into nanotechnology companies, you have to weigh the amazing benefits of nanotechnologies against what is right now a not well-understood risk. Is there going to be a regulatory environment to deal with? Are there going to be liability issues? The sooner we can get technical information in hand, the better.

Colvin: In the next few years, the answer is no. Nanotechnology, from an industry perspective, is just now developing, and actual products for consumers are not common. But I would say once the products are developed, probably the FDA [Food and Drug Administration] should look at it. I do know that nanomaterials are already used in sunscreens and also in cosmetics. The fact that they are used in those circumstances is of interest, and I do feel that eventually there will be a regulatory component to this industry.

TR: Have the nanoparticles used in sunscreens and cosmetics been tested? What do you tell people about the risks of these consumer products?
Colvin: To my knowledge, they have not been tested. Do I use sunscreens? Yes. Does it make me stay up at night? Actually, it doesn’t. Because the kind of diseases-if you look at other larger
particulate-based diseases-are ones that usually develop in workers who have acute exposures to the materials over decades. So I don’t feel that there is any chance occasional sunscreen use is unhealthy for me or my family. Still, it would be better for everyone to conduct thorough tests.

TR: Since nanoparticles are so small, can they go anywhere in the body?
Colvin: It is known that under the right circumstances nanoparticles can go into cells. This fact alone isn’t a cause for concern. Although the data is not systematic, below about 50 nanometers [about the size of a cold virus] they definitely tend to go in. Then, the question is: Where do they go? How do they distribute in the body? And the data on that is a little bit less clear. Smaller particles apparently circulate for much longer and in some cases can cross the blood-brain barrier. And they can certainly leak out of capillaries and get into the fluids between cells. So they can go places in the body that your average inorganic mineral can’t.

TR: Are there any areas where you feel efforts in nanotechnology should probably slow down?
Colvin: New types of solar cells or new methods for treating cancer, to take just two examples, offer amazing benefits to our society that outweigh any speculation about risks. I am less convinced that nanomaterials used in cosmetic products are worth the risk.

TR: Are you worried that public fears will hinder the development of nanotech?
Colvin: Ultimately, people have to make a cost-versus-benefit decision. The benefits of nanotechnology are well recognized by scientists and our federal government, which has put over a billion dollars into the area. But there will almost certainly be costs to implementing the nanotechnology. To try to stick your head in the sand and say, Oh no, all of nanotechnology will only result in perfectly safe and good technologies is simplistic. A number of very powerful organizations like Greenpeace, specifically the ones that went after genetically modified organisms, are beginning to look at nanotechnology. As a technical person, you have to listen to these groups and take their fears seriously.

If it were a perfect world, we wouldn’t think about this topic for 10 years. And then all the data would be there, and we would make a good decision. But the fact of the matter is that society will be forced to make a decision in the absence of data. I don’t know what the technical answers are yet. I can only tell you that it is a very diverse and complex problem. There are going to be a lot of different answers. And, yeah, I’m anxious about when that first paper on the health effects of nanomaterials publishes.