Nanoplastics as a potential environmental health factor: effects of polystyrene nanoparticles on human intestinal epithelial Caco-2 cells

The ubiquitous and increasing presence of micro-/nanoplastics (MNPLs) in our environment demands an urgent hazard assessment, in order to determine the potential risk they pose to human beings. Given the scarce information found in the literature regarding MNPL's effects over human cells, the aim of our work is to evaluate MNPL's ability to penetrate the cells, and their potential toxic/genotoxic effects. To this aim, we used polystyrene MNPLs, as they are a widespread model of synthetic polymer, using nanoparticles with (y-nPS) or without (nPS) a fluorescent label. The human colon adenocarcinoma Caco-2 cell line was used as the cellular target, as ingestion is one of the main entry routes of MNPLs. Different endpoints were analyzed as indicators of nanotoxicity, including cytotoxicity, ROS increase, genotoxicity, DNA oxidative damage and increase in the expression of stress-related genes.