Development of a sensitive immunoassay for detecting persistent contaminant dichlorodiphenyltrichloroethane (DDT) in food samples using a monoclonal antibody

Although gas chromatography is the gold standard for detecting the persistent organic pollutant dichlorodiphenyltrichloroethane (DDT), a quick and easy alternative is needed to detect this highly toxic pesticide in food and household products. Therefore, we developed a monoclonal antibody (mAb)-based assay for the sensitive detection of DDT. The mAb used in our assay demonstrated favourable binding affinity in the nanomolar range against 2,2-bis(4-chlorophenyl)acetic acid (DDA), a DDT analogue, which is considered higher than commercially developed antibodies. By optimizing the assay conditions, we were able to detect DDT and its closely related compounds, including dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyldichloroethane (DDD), and isomeric impurities. Our dot blotting assay demonstrated a detection limit of 0.9 ng/mL for DDT. Using computational modelling, we predicted the structure of the mAb and its interaction with DDT. Overall, this study provides insights for engineering mAb with improved sensitivity, facilitates point-of-care detection of toxic chemicals, including DDT, and offers a vital method for food safety monitoring and environmental protection. [Display omitted] •A sensitive monoclonal Ab-based assay detecting DDT and its derivatives is reported.•A detection limit of 0.9 ng/mL was demonstrated for DDT.•DDT spiked in milk and various juice samples was successfully quantified.•The antibody structure and its interaction with DDT were predicted.•This assay can be practically used to monitor potential DDT contamination in food.