Why is NTP evaluating nanoscale materials?
Nanoscale materials are already appearing in commerce as additives or modifications to industrial and consumer products and as novel drug delivery formulations. Commercial applications that result in human exposure may differ substantially for nanoscale versus “bulk” manufactured base materials. Currently, there is very little research focused on the potential toxicity of manufactured nanoscale materials. Published studies on the inhalation of ultrafine particles suggest that particle size can impact toxicity equally, if not more so, than chemical composition and hints at the complexity of the topic. The unique and diverse physico-chemical properties of nanoscale materials suggest that toxicological properties vary for materials of similar composition but differing size. There are indications in the literature that manufactured nanoscale materials may distribute in the body in unpredictable ways. Certain nanoscale materials have been observed to accumulate preferentially in particular
