Recent experiments involving "in vivo" testing of C-60 fullerenes, or "buckyballs" appears to conflicts with prior, "in vitro" tests and shows that the nanomaterials may not be toxic when inhaled.  Scientists at DuPont conducted experiments on lab rats by implanting the C-60 compound into the rats’ tracheas and then looked for signs of damage.

Upon review, the scientists determined that while the rats experienced  inflammation and cell damage one day after exposure, but that there appeared to be no long-term damage.  The long term exposure did not differ significantly than the responses noted in the control group.  These results seem to run counter to prior, in vitro tests performed on human cells, that showed some amount of damage. 

These results indicate a couple of points.  First, it is clearly too early in the testing of nanomaterials to declare them, carte blanche, safe or harmful.  Much more study is needed to resolve the apparent conflicts in data results.  Second, testing using in vitro methods alone may not be sufficient to gain a clear understanding of the health impacts on nanomaterials.  Third, using in vitro experiments to predict in vivo responses may be inappropriate. 

These latest results underscore the need for more, and more thorough, research involving nanomaterials and the potential health impacts.  Any stated conclusion concerning the safety of nanomaterials, either that they are safe or toxic, is premature at this stage, and such statements should be viewed with an air of skepticism.