In vitro toxicological assessment of iron oxide, aluminium oxide and copper nanoparticles in prokaryotic and eukaryotic cell types

Metallic nanoparticles (NPs) have a variety of applications in different industries including pharmaceutical industry where these NPs are used mainly for image analysis and drug delivery. The increasing interest in nanotechnology is largely associated with undefined risks to the human health and to the environment. Therefore, in the present study cytotoxic and genotoxic effects of iron oxide, aluminium oxide and copper nanoparticles were evaluated using most commonly used assays i.e. Ames assay, in vitro cytotoxicity assay, micronucleus assay and comet assay. Cytotoxicity to bacterial cells was assessed in terms of colony forming units by using Escherichia coli (gram negative) and Bacillus subtilis (gram positive). Ames assay was carried out using two bacterial strains of Salmonella typhimurium TA98 and TA100. Genotoxicity of these NPs was evaluated following exposure to monkey kidney cell line, CHS-20. No cytotoxic and genotoxic effects were observed for iron oxide, and aluminium oxide NPs. Copper NPs were found mutagenic in TA98 and in TA100 and also found cytotoxic in dose dependent manner. Copper NPs induced significant (p<0.01) increase in number of binucleated cells with micronuclei (96.6 +/- 5.40) at the highest concentration (25 mu g/mL). Copper NPs also induced DNA strand breaks at 10 mu g/mL and oxidative DNA damage at 5 and 10 mu g/mL. We consider these findings very useful in evaluating the genotoxic potential of NPs especially because of their increasing applications in human health and environment with limited knowledge of their toxicity and genotoxicity.