Zinc oxide nanoparticles induce oxidative stress and genotoxicity in human liver cells (HepG2)

Zinc oxide (ZnO) is being used worldwide in consumer products and industrial applications. As humans are being directly exposed to ZnO nanoparticles (NPs) through different routes, it is likely that the NPs would gain access to the liver. Therefore, the present study investigated the cytotoxic and genotoxic potential of ZnO nanoparticles in human liver cells (HepG2). The MTT and neutral red uptake assay showed a significant (p < 0.05) concentration and time dependent toxicity after 12 and 24 h at 14 and 20 microg/ml. A (p < 0.05) significant increase in DNA damage was observed in cells exposed to ZnO NPs for 6 h as evident with an increase in the Olive tail moment (OTM) and % tail DNA in the Comet assay. The generation of intracellular reactive oxygen species further suggest the role of oxidative stress in ZnO nanoparticle mediated DNA damage and cytotoxicity in HepG2 cells.