Tuesday, June 20, 2006

Nanotechnology and Nanotoxicity


Nanotoxicology is back in the news.  For background on nanotoxicology, see Nanotoxicology Review.  Nanotechnology has been widely dispersed without much understanding of the biological effects of nanoparticles.  An animal study by Veronesi published June 7 in Environmental Science and Technology on biological effects of titanium dioxide nanoparticles suggests that some nanoparticles cause substantial neurological damage.  Given the widespread use of such nanoparticles, some quick research to confirm these findings is in order.  Link: ScienceNOW

Hundreds of tons of engineered, microscopic particles enter the environment every year, yet little is known of their biological effects. Now, a study of ultrafine particles of titanium dioxide (TiO2)--used in manufacturing, personal care and food products, and as drug carriers--indicates that even low concentrations can produce harmful "free radicals" in brain cells. The findings underscore the need to learn more about how such tiny particles interact with living tissues, the researchers say.

Previous studies have revealed that many nontoxic materials become harmful at particle sizes of less than 100 nanometers. Specifically, they can trigger the production of biologically reactive, oxygen-containing molecules such as free radicals. In addition, some types of particulate matter can enter the brain once they get into the bloodstream. Little is known about the biological effects of TiO2, but its widespread use and distribution means that humans and other animals could be widely exposed.

To investigate the biological effects of TiO2, Bellina Veronesi, a neurotoxicologist with the U.S. Environmental Protection Agency in Research Triangle Park, North Carolina, and her colleagues exposed mouse microglia--cells that protect the brain from invaders such as viruses and foreign chemicals--to a solution containing minute concentrations of TiO2. The microglia engulfed the particles and released bursts of reactive oxygen molecules for 2 hours. This didn't damage the microglia, but Veronesi says prolonged exposure to these compounds can damage neurons. In fact, a similar mechanism is thought to underlie some cardiovascular and neurodegenerative diseases, including Parkinson's and Alzheimer's.


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