Generation of Polystyrene-Specific Antibodies for Developing Immunoassays to Analyze Microplastics and Nanoplastics

Micro- and nano-plastics (MNPs) are emerging pollutants that have drawn worldwide attention due to their negative impacts on the health and sustainability of our ecosystem. Quantitative analysis of MNPs, especially those at nano-scale, is still challenging due to lack of efficient analytical methods. Different antibody-based immunoassay platforms have been well established and readily available for rapid, specific, and quantitative analysis of targets with a broad size range. The key to developing immunoassays for MNP analysis is to generate plastic-specific antibodies, which is still lacking. In this study, we conjugated the nanoparticles of polystyrene (PS), a widely studied representative MNPs, to different carrier proteins for rabbit immunizations. The PSspecific antibodies were significantly induced upon immunization (up to 128-fold increase in IgG titer), which was validated by multi-tier immunoassays using different PS products. Notably, the PS-specific antibodies did not react with polypropylene, a different plastic. Using PS antibody-based enzyme-linked immunoassay, we further demonstrated suitability of the antibody-based immunoassay for quantitative analysis of the PS particles that have been exposed to diverse matrices. Together, this study, for the first time, demonstrates the feasibility of producing plastic-specific antibodies, and lays the groundwork to develop innovative antibody-based immunoassays for future risk assessment and management of MNPs, particularly those at nano-scale.