<div>Background:&nbsp;Nanoplastics (NPs) become one of the most threatening substances for living organisms in the aquatic and terrestrial environments. Due to their small size and high surface area, few studies have revealed their toxic impact on mainly marine organisms. However, there is scarcity on NPs impact on mammalian cells.&nbsp; 
 
Methods: We used 200-900 nm polyethylene nanoparticles (PE-NPs) to evaluate their cytotoxic and genotoxic effects on mammalian Vero E6 cell line using MTT and Comet assays. 
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Result: Characterization of the selected PE-NPs confirmed their nano spherical shape, size and their low-density type. Serial dilution of PE-NPs decreases cell viability with 50% inhibition concentration (IC50) 91 &mu;g/mL (at 24 h sampling time), 26 &mu;g/mL (48 h) and 22 &mu;g/mL (72 h) and an average IC50&nbsp;= 46 &mu;g/mL. Treatment of Vero E6 cells with the average IC50 significantly affects the genomic integrity by decrease of % DNA in head, increase of % DNA in tail, tail length (&mu;m) and tail moment, in a time-dependent manner. Therefore, PE-NPs of the low-density type, that is widely used in different products including coatings and films, have cytotoxic and genotoxic effect on mammalian cells. NPs deserves more attention and further studies are needed to focus on their molecular mechanisms in vitro.</div>

Cytotoxic and Apoptotic Effects of Polyethylene Nanoparticles on Normal Monkey Kidney Vero E6 Cell Line