A novel bismuth-based lead-free piezoelectric transducer immunosensor for carbaryl quantification

A novel BNT-BKT-BT piezoelectric ceramic immunosensor, tested for quantification of the pesticide carbaryl is here presented. The measuring format was based on a competitive immunoassay of immobilized conjugate using monoclonal antibodies (MAbs) as specific immunoreagent. The immunosensor is able to detect concentrations of the analyte from one and up to three orders of magnitude below the reported values of high-and low-frequency quartz crystal commercial resonators (HFF-QCM and QCM), respectively. Furthermore, the minimum content of quantified carbaryl is 0.11 mu g L-1, which is clearly lower than reported values of any commercial quartz-based biosensors. Such measurement characteristics are only possible due to the high electromechanical coupling factor (k(t)) of the Bi-based piezoelectric ceramic, approaching the commercial QCM, HFF-QCM and ELISA techniques and strongly enhancing the sensitivity of the immunoassay.