Newsclip

One million nanotubes could fit into this period.

By Carolyn Y. Johnson, Globe Correspondent | February 15,

2005Supporters say nanotechnology someday will allow doctors to hunt down cancers early, computers to shrink small enough to fit inside blood vessels, and soldiers to fight less deadly wars. These infinitesimally small devices are already in a variety of products, including power tennis rackets and wrinkle-free dress shirts.

But, over the past year and a half, scientists and consumer advocates have begun to worry about the unintended consequences of such technologies. Studies have shown that nanoparticles can accumulate in the brains of fish and cause damage. Preliminary evidence has shown they may build up in lungs.

What some consider more frightening is how little is known about how the particles interact with the environment and human body. Researchers who have been working at this atomic scale for a decade have yet to understand what happens to the particles after someone, for instance, sends a perfectly safe tennis racket to the landfill.

Now, a half-dozen US and foreign regulatory agencies are grappling with how -- and whether -- to protect consumers, lab workers and the environment from the next big thing in science and shopping. Nanotechnology research will receive $1 billion in federal funding this year -- roughly 10 percent of which will be funneled toward studies of the technology's risks.

"Society has been through a number of very difficult lessons with asbestos, with a lot of the work on genetically modified foods," and with DDT, said Clayton Teague, director of the National Nanotechnology Coordination Office, a federal research and development program. "I assure you government, industry, and academia have not forgotten -- they are very prominent in people's memories."

For the most part, nano-sized devices are simply scaled-down versions of familiar materials, like carbon, that people come in contact with every day. But when these chemicals are packaged at thousandths the size of a human hair, they can act in completely new and different ways -- with novel properties that make up nanotechology's allure and risks.

On the bright side, fabric shrouded with nanofibers can repel stains and -- perhaps someday -- bullets. Nanodevices harder than diamonds and lighter, stronger and more flexible than steel can improve the performance of a tennis racket, golf club, car bumper, and tires. Because of their small size, circuits can be made more compactly, sunscreen can be made transparent, and medicines can be better targeted.

But no one knows yet whether the same devices also might ferry toxins right past the body's normal defenses. The body is normally very good at keeping foreign particles out of the brain, but nanotechnologies smaller than a cell can seep through. And research has long shown that naturally occurring nanoparticles -- like viruses and air pollution -- can accumulate in the lungs.

"The key point of concern is, because these particles are so small, they don't necessarily follow the same toxicologic principles that we understand," said Dave Kriebel, an epidemiologist at University of Massachusetts at Lowell.

The research that has been done so far strongly suggests the need for further study, several scientists said.

Last year, Eva Oberdarster, a Duke University scientist, found that largemouth bass exposed to soccer-ball shaped carbon nanoparticles for 48 hours had a seventeenfold increase in brain damage compared with fish that were not exposed. Oberdarster is now testing so-called fullerenes on another species of fish, and said that preliminary results show the same damage to fatty tissues in the brain.

So far, though, the damage she's tracked has not led to any health problems.

"They are still feisty, they are still behaving normally," she said, so further study would be needed to understand the long-term effects, if any, of such damage. The big problem for the researchers and federal agencies dedicated to preventing such dangers is that they don't know exactly what kind of protection is needed.

Researchers are now studying ways to make nanotechnologies safer for those who encounter them the most -- themselves, and workers who manufacture nano-products.

At a new center based at Northeastern University, researchers have begun a detailed examination of nanotechnologies as they are being developed -- instead of later.

"No one knows how this affects humans and the workplace," said Ahmed Busnaina, the director of Northeastern's Center for High Rate Nanomanufacturing.

Efforts like the one at Northeastern are growing more common as scientists launch a preemptive attack on nanotech's dangers. Among their advances: Busnaina and his colleagues are attempting to construct nano-sized circuit boards in a completely liquid environment to prevent the tiny wires from becoming airborne and readily inhaled into the body.

Researchers at Rice University in Houston -- where fullerenes were discovered -- have found a way to create new versions that won't act like the particles in Oberdarster's fish experiment.

Those who say that nanotechnology could transform the world -- for better or worse -- acknowledge that they can't do much now other than wait for more research to answer the many questions raised by nanotechnology.

"There are little hints, little bits of evidence that there might be problems," Kriebel said. "But as yet . . . we just don't know the rules."

© Copyright 2005 The New York Times Company