Comparison of toxicities from three metal oxide nanoparticles at environmental relevant concentrations in nematode...

Nematode Caenorhabditis elegans has been developed in a variety of environmental studies to address adverse effects of a wide range of toxicants. In the present study, we compared the toxicities of three metal oxide nanoparticles (NPs) including TiO(2)-NPs, ZnO-NPs, and SiO(2)-NPs with the same nanosize (30 nm) after prolonged exposure from L1-larvae to adult at environmental relevant concentrations. Our data indicated that the adverse effects were detected in nematodes exposed to TiO(2)-NPs and ZnO-NPs at concentrations more than 0.05 μg/L and SiO(2)-NPs at concentrations more than 5 μg/L with locomotion behavior and ROS production as endpoints. With growth, locomotion behavior, reproduction, and ROS production as endpoints, toxicity order for the examined metal oxide NPs was: ZnO-NPs>TiO(2)-NPs>SiO(2)-NPs. In nematodes exposed to the examined metal oxide NPs, ROS production was significantly correlated with lethality, growth, reproduction, and locomotion behavior. Moreover, treatment with antioxidants of ascorbate or NAC effectively inhibited the formation of oxidative stress and retrieved the adverse effects of TiO(2)-NPs, ZnO-NPs, and SiO(2)-NPs on survival, growth, reproduction and locomotion behaviors in nematodes. Our data demonstrated the subtle toxicity differences of different NPs exposure at environmental relevant concentrations in C. elegans.