3-Phenoxybenzoic acid (3-PBA) is a human urinary metabolite of different pyrethroid insecticides and can be used as an indicator for the human exposure to these pesticides. An ultrasensitive nanobody-based electrochemical immunoassay system was designed by immobilization of 3-PBA-bovine serum albumin conjugate onto citric acid decorated nylon nanofibrous membrane modified screen-printed carbon electrode (SPCE). The 3-PBA detection was via a direct competition between free 3-PBA in the sample and immobilized antigen for binding to 3-PBA nanobody-alkaline phosphatase. The employment of the nylon nanofibrous membranes in the immunosensor assembling exhibited improvement of electrochemical performance of the electrode by more than 5 times comparing with nylon casted membranes. The integration of the nanofiber, nanobody, and electrochemical technologies introduced a highly sensitive and selective immunosensor for 3-PBA detection in a range of 0.0008 to 1 ng mL-1, with a detection limit of 0.64 pg mL-1. Furthermore, the established immunosensor showed good feasibility as a promising alternative to conventional monitoring of human exposure to pyrethroid insecticides, with good specificity, reusability, and stability over the time.

Novel nanobody-based-electrochemical immunosensor on nylon nanofibrous membranes for detection of 3-phenoxybenzoic acid in human urine

2019 Fall National Meeting

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