Posted: Dec 20, 2006

Naturally glowing carbon nanotubes tracked in vivo

(Nanowerk News) Tracking nanomaterials in live organisms continues to be a tricky process for researchers searching for toxicological and environmental effects of these new materials. But a team of scientists found a way to take advantage of carbon nanotubes’ seemingly ready made tracking system, using their built-in reflectance characteristics to pinpoint the materials in live rabbits.
Chemists at Rice University and the University of Texas M.D. Anderson Cancer Center discovered in 2002 that nanotubes fluoresce, or emit light, in the near-infrared range. The team has now developed a method to locate single-walled carbon nanotubes injected into rabbits’ bloodstreams with that fluorescence, rather than a tag or coating. The study was published online November 29 in Proceedings of the National Academy of Sciences ("Mammalian pharmacokinetics of carbon nanotubes using intrinsic near-infrared fluorescence").
The researchers found no immediate adverse health effects and wrote that the nanotubes seem to have been evacuated from the animals’ blood and livers within an hour. However, many toxicologists studying nanomaterials say that much more work remains to be done before they are proven safe.
Source: Environmental Science & Technology