Understanding the interaction of micro(nano)plastics with simulated saliva, lysosomal and Gamble’s fluids and their impact on human lung epithelial A549 cells

Abstract Micro(nano)plastics are considered an emerging threat to human health since they have potential to interact with biological systems and already been found in the human body, e.g., lungs. However, limited data is available for their behavior under biological conditions and impact on human cells, specifically alveolar epithelial cells. In this study, micro(nano)plastics weathered to various simulated biological fluids (saliva, artificial lysosomal fluids, Gamble’s solution) during 2 h to 80 h. Pristine and weathered plastic particles were characterized by their surface chemistry, zeta potentials, and elemental composition. After, various toxicological endpoints (mitochondrial membrane potential, lactate dehydrogenase, protein, and antioxidant levels) were examined through A549 lung carcinoma cells. The surface characteristics of micro(nano)plastics and the toxicological endpoints of A549 were influenced by the simulated biological weathering, specifically at high concentration of micro(nano)plastics and increasing exposure under biological conditions. The results also indicated that toxicological endpoints had strong linked with the chemistry of plastics and included the multiple processes to the response of the plastics, for instance, the cell membrane integrity and mitochondrial activity were declined with the micro(nano)plastics under saliva weathering, contrarily, their protein and antioxidant activities increased. However, different biological pathways were obtained under artificial lysosomal fluid and Gamble’s solution.