Nanoplastic-induced DNA damage in mammalian cells

Plastic pollution is a growing public health concern. Nanoplastics (NPs) are defined as plastic particles <1,000 nm diameter. Microplastics and NPs have been detected in foods, water, and air. In this mini-review, we assess the genotoxic effects of primary (polystyrene) and secondary (‘true-to-life’) NPs in cultured mammalian cells. Studies were identified in the PubMed, Scopus, and Web of Science databases. Narrative review of the literature was supported by statistical analysis of associations between reported genotoxic effects (positive or null effects, or semi-quantitative indicators of effect size) and cell type (immune vs. non-immune cells), genotoxicity endpoint (repairable vs. permanent DNA lesions), maximal exposure concentration, particle size (> the defined size of nanoparticles, 100 nm) and surface modification in polystyrene NP studies. Results from 36 studies show that, as determinants of the effects of polystyrene NPs, biological differences (cell type and genotoxicity endpoint) are more important than the exposure concentration or the particle characteristics (particle size and surface modification). There is higher consistency or stronger effect in studies on immune cells vs. non-immune cells, and some evidence of stronger effect on permanent DNA lesions (mainly micronuclei, MN) vs. repairable damages (mainly, comet assay endpoints). Results from nine studies on true-to-life NPs from polyethylene terephthalate (PET) plastics suggest genotoxic potential, although differences in plastic degradation methods may affect the level of genotoxicity. Overall, the analysis shows that primary (polystyrene) and true-to-life (PET) NPs can generate DNA damage in cultured mammalian cells.