8 February 2006

Spotting toxic nanoparticles

Researchers suggest a strategy that could weed out dangerous nanoparticles.

Technology Review reported the novel properties of nanoparticles mean they could find uses in applications as different as solar power and cancer treatment. Indeed, some nanoparticles have already made it into commercial products, notably, cosmetics.

Many experts worry, however, the unique properties of these particles could make them toxic, and fear over the potential dangers of nanoparticles has led to increasing calls for tests and regulations. However, the sheer number of new nano materials will make evaluating all of them impossible. The result: either harmful material could reach consumers, or, in an effort to play it safe, restrictive regulations could arise that clamp down on innovation.

The authors of a review of past studies published last week in the journal Science suggest a strategy for screening the most dangerous nanoparticles more efficiently, which could help avert potential disasters and allow the development of new technologies to continue.

The strategy would use “predictive toxicology,” which looks for subtle signs that the cells in a culture are starting to defend themselves, indicating the particles they have been exposed to could be dangerous.

Andre Nel, professor of medicine at UCLA, and one of the authors of the paper, said existing work on the toxicity of particles that are byproducts of industrial and natural processes should help researchers to identify the telltale danger signs in cell-culture screening of nanoparticles.

According to the review, researchers studying particle toxicology have already identified molecular mechanisms that trigger when dangerous particles come into contact with living cells. They have found dangerous particles create reactive forms of oxygen that damage cells. At low concentrations of these molecules, cells can defend themselves by producing anti-oxidants. As concentrations increase, however, cells become inflamed or die. At each stage, the cell produces signs that can be screened for, using cell cultures that have been exposed to these new particles.

For related information, go to www.isa.org/sensors.