Comparative toxicity of microplastics obtained from human consumer products on human cell-based models

Originally developed to conserve natural resources, plastic has become a global pollution issue due to inadequate waste management. The dispersion and weathering of plastic waste in the environment generate micro-sized particles. Despite extensive research on the toxicological effects of pristine polymers, the impact of microplastics (MPs) from consumer plastics is poorly understood. This study investigated the cytotoxic and genotoxic effects of cryo-milled single-use plastic products (fork and cup) on eight cell lines (Caco-2, HEK001, MRC-5, HMEC-1, HepaRG, HMC-3, and T47D) at concentrations from 0.01 to 100 μg/mL. Results showed that 100 μg/mL of MPs did not significantly affect cell viability in Caco-2, HEK001, MRC-5, and T47D. However, HMEC-1 and HMC-3 exhibited decreased viability with 10-100 μg/mL of fork particles, while HMC-3 and HepaRG showed reduced viability with 100 μg/mL of cup particles. Conversely, cup particles increased HMEC-1 proliferation at 0.1-100 μg/mL. Comet assay data indicated that both fork and cup exposure led to elevated DNA fragmentation in HMEC-1 and HMC-3 cells. These findings indicate that MPs from consumer-grade plastics may exhibit cytotoxic and genotoxic effects, with endothelial and microglial cells being particularly susceptible.