The introduction of any new materials or products will raise questions about side effects, said Kevin Ausman, executive director for Rice University's Center for Biological and Environmental Nanotechnology.
But practicing science at the nanometer level, where matter is manipulated at the atomic or molecular scale, is not inherently dangerous, he told NanoTech 2002 attendees.
"If you have a nanomaterial made of something that is toxic on the macro scale, the nano version will likely be toxic as well," Ausman said. "Nanomaterials are a prime opportunity for (science) to take a proactive approach (to public concerns)."
Those concerns now include a demand for an immediate halt to all nanoscience work, issued by the Action Group on Erosion, Technology and Concentration, which is also called the ETC Group.
The group contends that nanotech's work with the building blocks of matter, instead of existing products, has allowed it to progress outside the view of the public and governmental agencies.
The drastic proposal is intended to allow for a more thorough examination of how nanomaterials interact with living systems, but it would be self-defeating, Ausman said. Bulk quantities of engineered nanomaterials are only now becoming available and preventing the creation of additional ones would hobble any attempt to gauge their environmental impact, he said.
"We have to provide a measured response to (the moratorium call) and back up that response with actual data on health and environmental impacts instead of speculation," Ausman told the conference.
It is important for nanotech researchers to avoid the mistakes that biotech companies made by trying to shrug off public concerns, he added.
"(ETC Group) made comparisons to biotechnology in terms of policy," Ausman told United Press International after his presentation. "In terms of the science ... if we can sit down and look at the similarities and differences, I don't think nanotechnology is worthy of that comparison."
For example, genetically modified organisms often can reproduce, while nanomaterials cannot, Ausman said.
The sorts of nanostructures under examination in labs around the world also aren't designed to be ingested, unless they are medical applications being examined by agencies such as the Food and Drug Administration, he told UPI.
One example of such a nanomedical approach that Rice's CBEN is studying involves spheres of a few dozen silicon atoms each, coated with gold nanoparticles, Ausman told the conference. The spheres are attached to antibodies or other biological structures that only bond with cancer cells.
After the spheres enter a body and accumulate on tumors, shining a near-infrared laser on the body heats up the gold, killing the cancer cells while having no effect on other tissue, which is transparent to light at that wavelength, he said.
This technique is undergoing animal testing and shows promise for human trials, Ausman said.
An attendee asked what would happen if the bonding agents were chemically altered in the body and mistakenly attached to healthy tissue. While the spheres and the gold are biologically inert, Ausman said, and it is very unlikely enough spheres would gather in the wrong place to cause heat damage, such questions are just the reason that continued research should be conducted.
Other questions indicated that attendees agreed no moratorium is necessary. One researcher asked Ausman about a supposed analogy between asbestos fibers and nanotubes, structures of carbon or other materials with walls only one atom thick.
"There are serious questions about the validity of the analogy," Ausman replied. "The length of a nanotube is roughly the same as an asbestos fiber, but the diameters are very different; the fiber is very rigid and can't be engulfed by (cells in the immune system); a nanotube is more flexible and might be absorbed. What's really going to settle the issue is to do the experiments."
NanoTech 2002, which is co-hosted by the American Institute of Aeronautics and Astronautics and the Center for Nanospace Technologies, looks at both microelectromechanical systems and nanotechnology.
The conference will conclude with a workshop addressing several application areas, including energy and life sciences, to try to identify cost-effective nanotech alternatives to current applications.
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