Effect of size and shape on toxicity of zinc oxide (ZnO) nanomaterials in human peripheral blood lymphocytes

The multi-industrial applications of zinc oxide nanomaterials (ZnO NMs) lead to increasing exposure to humans. Though the ZnO nanoparticles (NPs) toxicity had been evaluated previously, toxicity of other forms of ZnO nanomaterials has not been evaluated. In this study, cytotoxicity and genotoxicity of four different types of ZnO NMs were evaluated using human peripheral blood lymphocytes (HPBL). In addition, the effect of anti-oxidants on ZnO NMs induced toxicity was also evaluated. Our results suggest that, size and shape of the nanomaterials have profound effects on their toxicity. The NPs and nanorods (NRs) possessed higher level of oxidative potential and ROS generation capacity than microparticles (MPs) and microrods (MRs). In contrast, MPs and MRs possessed higher level of lipid peroxidation capacity. The smaller NPs are more genotoxic while larger MPs and MRs were more cytotoxic in nature. Treatment with vitamin C or Quercetin significantly reduces the genotoxicity associated with ZnO NMs. The influence of size and shape in mediating NMs toxicity should be taken into account and the possible supplementation of anti-oxidants might mitigate the toxicity.