A sensitive biosensor based on carbon nanohorn/rhodamine B for toxicity detection of polystyrene microplastics and typical pollutants

Microplastics have worldwide accumulated in water and coexisted with different toxic chemicals, which ultimately threaten human health. However, the combined cytotoxicity of microplastics and typical pollutants is still limited. Therefore, it is essential to evaluate the individual toxicity of microplastics and the combined toxicity with other contaminants rapidly and accurately. In this study, a sensitive electrochemical cell-based sensor based on a carbon nanohorn/rhodamine B modified electrode was proposed. Normal human liver (L-02) cells were used as the ideal model for toxicity evaluation. The sensor was used to detect the cytotoxicity of polystyrene microplastic (PS), bisphenol A (BPA), pentachlorophenol (PCP), and lead (Pb2+). The half inhibition concentration (IC50) values of PS, BPA, PCP, and Pb2+ to L-02 cells were 286.34 μg/mL, 78.85 μM, 67.87 μM, and 60.12 μM, respectively. The combined toxicity of PS and typical pollutants (BPA, PCP, Pb2+) revealed an additive effect. Moreover, the mechanism underlying the cytotoxicity of microplastics and three pollutants was investigated from the perspective of oxidative stress and cellular apoptosis. The toxic effects inhibited cell division and growth, with apparent oxidative stress damage and increased apoptosis. This study provideds a sensitive tool for toxicity detection of microplastics and typical pollutants, and reveals the possible mechanisms involved.