Toxicity comparison of nanopolystyrene with three metal oxide nanoparticles in nematode Caenorhabditis elegans

Using Caenorhabditis elegans as an animal model, we compared the toxicity between nanopolystyrene and three metal oxide nanoparticles (NPs) (Al₂O₃-NPs, TiO₂-NPs, and SiO₂-NPs). After exposure from L1-larvae to adult day-1, nanopolystyrene (100 μg/L) reduced brood size and induced severe germline apoptosis, and nanopolystyrene (10-100 μg/L) decreased locomotion behavior, induced obvious reactive oxygen species (ROS) production, and activated noticeable mitochondrial unfolded protein response (mt UPR). Using several endpoints (lethality, development, reproduction, and/or locomotion behavior), we found that nanopolystyrene could induce more severe toxicity than SiO₂-NPs, although nanopolystyrene did not cause the toxicity comparable to that in Al₂O₃-NPs or TiO₂-NPs exposed nematodes. Our data will be useful for understanding the exposure risk of nanopolystyrene on environmental organisms. Moreover, the detected toxicity difference between nanopolystyrene and three metal oxide NPs were associated with the differences in both induction of oxidative stress and activation of mt UPR in exposed nematodes.