April 2003

Measuring the Risks of Nanotechnology

Chemist Vicki Colvin on the safety of nanotechnology.

By David Rotman

Vicki Colvin

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Position: Director, The Center for Biological and Environmental Nanotechnology at Rice University

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Issue: The safety of nanotechnology. Do breakthroughs in nanotechnology-widely hailed for their potential in biomedicine and materials science-present unique health and environmental dangers that need to be studied?

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Personal Point of Impact: Colvin's nanochemistry group, which makes new kinds of nanoparticles, is beginning to work with toxicologists, biologists, and bioengineers to evaluate the unintended biological effects of these materials.

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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.