Wednesday September 30 2009
CEA
Visualizing carbon nanotubes in vivo to investigate their effects on health
CEA
There has been a flurry of research into the toxicity of nanometer-scale elements, yet a CEA team has managed to develop an isotopic labelling technique that enables extremely reliable visualization of how carbon nanotubes behave in living organisms. The results, which have been published online in the 29 September issue of the Journal of the American Chemistry Society, pave the way to more far-reaching toxicology studies that will finally clear up whether or not these compounds are toxic.
Carbon nanotubes possess unique mechanical properties that make them potentially useful in a wide array of industrial applications, and they are starting to find their way into our everyday environment. However, by the same token, their physical and chemical properties – size, fibrous form and exceptional chemical stability – have brought them under the scrutiny of the regulatory health authorities who are investigating the risk profile in the event of human exposure.
The core issue facing researchers is to establish whether the body would be able to eliminate carbon nanoparticles following an exposure event.
Teams from the CEA’s Life Sciences and Materials Sciences divisions have joined forces to tackle this question, within the framework of the cross-disciplinary Nanosciences programme. They have developed synthesis protocols making it possible to tag carbon nanotubes with 14C atoms² but altering neither their structure nor their properties.
This radiolabeling technique enabled the teams to analyze rats subjected to carbon nanotube exposure and chart the resulting tissue distribution in vivo, using imagers capable of detecting 14C radiation.
First-run biodistribution trials have already demonstrated that once these nano-objects have entered the body, they are very slow to clear.
[1] A size of less than a millionth of a millimetre, i.e. 109 of a metre.
[2] Carbon14 is a radioactive isotope of carbon, annotated as 14C. It is exploited for use as a biological tag. This same element is well-known for its use in radiocarbon dating, which measures the 14C radioactivity in the organic matter whose age needs to be determined.