Cytotoxicity of UV-degradated polystyrene nanoplastics in co-culture model of inflammatory bowel disease.

Nanoplastics (NPs) are plastic particles smaller than 100 nm that are found in various environments, such as the ocean and the atmosphere. In the environment, NPs are inevitably exposed to ultraviolet (UV) irradiation and undergo an aging process. In the patients with inflammatory bowel disease (IBD), the exposure of NPs might induce breakdown of the intestinal immune system and inflammatory response. However, the toxicity of NPs remains unclear against human health. The present study investigated the characterization of polystyrene-nanoplastics (PS-NPs) under UV irradiation and its toxicity using IBD co-culture cell models (differentiated Caco-2/THP-1 cells). The virgin PS-NPs (50 nm) were continuously treated with UV irradiation (250-450 nm, 40 mW/cm2) for 3-24 hrs to obtain aged PS-NPs. The particle size and the poly-dispersion index (PDI) values of aged PS-NPs did not change compared with the virgin PS-NPs. On the other hand, the negatively charge of the zeta potential of aged PS-NP decreased by the UV irradiation. Furthermore, the peaks attributed to OH groups and C=O groups were detected in the surface of aged PS-NPs by fourier transform infrared spectroscopy (FT-IR) analysis. Then, the aged PS-NPs were exposed to IBD co-culture models at the concentration of 0–100 μg/cm2 for 24 hrs and measured the level of lactate dehydrogenase (LDH) for cell toxicity. The aged, i.e., photodegraded PS-NPs under UV radiation caused more severe toxicity than virgin PS-NPs. This finding can provide an important insight for understanding human health risks from NPs in the environment. Also see: https://micro2024.sciencesconf.org/559311/document