Ultrahigh reactivity provokes nanotoxicity: Explanation of oral toxicity of nano-copper particles

Recently, studies on the biological effects of nanomaterials show signs that some of the manufactured nanoparticles exhibit unexpected toxicity to living organisms. It has previously been reported that the copper particles possess size-depended toxicity. In this paper, we propose that the ultrahigh chemical reactivity of nano-copper results in the specific nanotoxicity which is fully proved by in vitro and in vivo experiment. Using chemical kinetics study (in vitro) and blood gas and plasma electrolytes analysis (in vivo), we found that high reactivity cause the big toxicological difference between small size (23.5 nm) and big size (17 mu m). The result is also consistent with biochemistry assay, pathological examination and copper content measurement in renal tissue in vivo. For chemical reactive nanoparticles, metallic nano-copper for instance, both the particles themselves and the resulting product (copper ion) should be fully explored. The nano-copper particles may not compromise the mice directly, however, they lead to the accumulation of excessive alkalescent substance and heavy metal ions (copper ions) culminating the metabolic alkalosis and copper ion overload. (C) 2007 Elsevier Ireland Ltd. All rights reserved.