Investigation of nanoplastic cytotoxicity using SH-SY5Y human neuroblastoma cells and polystyrene nanoparticles

Nanoplastics have spread widely throughout not only the oceans but also the atmosphere, and recently created great concern about human health relevant to ingestion and accumulation of the nanoparticles by aquatic organisms in the human food-chain. However, how the nanoplastics have an affect on actual human body remains largely unknown, and in particular, little knowledge about nanoplastic exposure to the nervous system in human has been obtained in vitro and still less vivo. Here, we evaluated how much concentration of nanoplastics had a direct impact on cells in the nervous system as the fundamental information. Specifically, the cytotoxicity was investigated by exposure of polystyrene nanoparticles (PS) to cultured neural cells, human neuroblastoma cells, SH-SY5Y. Our results demonstrated that the PS exposure induced the cytotoxicity in the cells promoted differentiation into neuronal phenotype, and the adverse effect was comparable to or exceed that of acrylamide, a well-recognized potent neurotoxin. Also, the cells under PS exposure exhibited shrinkage of neurite outgrowth, morphology alteration and swelling of the nuclei, and spilling of intracellular components. Moreover, our findings indicate that the concentration of nanoplastics caused the cytotoxicity on neuronal cells is likely to be much higher than those predicted from the marine environment.