A competitive love wave immunosensor for detection of okadaic acid based on immunogold staining method

This work describes an immunosensor for the determination of okadaic acid (OA) using a Love-wave sensor with the immunogold staining method. In this assay, OA-BSA was captured by the anti-BSA antibody (BSA-MAb) bond with staphylococcal protein A (SPA) on the sensor surface via Fc regions. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to monitor the fabrication steps of immunosensor using the redox probe of K 3 Fe(CN) 6 . An indirect competitive immunoassay format was employed to detect OA after the immunosensor was prepared and gold nanoparticles (AuNPs) were introduced to amplify the phase signal. The results demonstrated that developed immunosensor was able to specifically respond to OA ranging from 10 to 150   ng/mL, providing limit of detection of 5.5   ng/mL. When applied to determine OA concentration in real sample, the results agreed well with those obtained by the commercial ELISA assay. The developed immunosensor is therefore suitable and has great application potential in detection of OA in shellfish.