Cytotoxic Effect and Mechanism of Nano-Sized Polystyrene Degraded by Rhodococcus Ruber

Abstract

Biodegradation using various microbes has emerged as a promising solution to issues involving plastics. However, the altered physicochemical properties of NPs that can be induced by biodegradation and their effects on cellular behaviors are unclear. Here, we generated NPs (bPS(r)s) using polystyrene (PS) and Rhodococcus ruber to assess the changes in physicochemical properties and the cytotoxic effects in keratinocytes. Compared to PS NPs, the biodegradation of PS using R. ruber induced a decrease in particle size, extant extracellular polymeric substances, shape and functional group changes, surface charge alteration, and enhancement of particle dispersion. The resulting physicochemical changes in bPS(r)s significantly increased the cytotoxicity, leading to massive intracellular reactive oxygen species (ROS) generation, high apoptotic activity, decreased cell proliferation, and upregulated inflammation-related gene expression compared with PS NPs. Overall, our findings suggest new aspects and methods for future studies on biodegraded NPs.

Keywords: Biodegradation of plastic, Cytotoxicity, Physicochemical property alternation, Polystyrene, Rhodococcus ruber