Electrochemical Immunosensor for Detection of Vibrio parahaemolyticus Based on Faradaycage-Type Anodic Stripping Voltammetry

Abstract

This paper aims to develop a Faradaycage-type immunoassay mode combined with anodic stripping voltammetry for Vibrio parahaemolyticus (VP) detection. Detection antibody (dAb) immobilized on GO-supported AgNPs (AgNPs@GO) was used as the detector unit, while capture antibody (cAb) immobilized on Fe3O4 particles cAb@Fe3O4 as the capture unit. The immunoassay was performed on a magnetic glassy carbon electrode via immunoreactions among the capture unit, VP and the detector unit. The detection sensitivity is expected to be considerably enhanced owing to two reasons: (1) large amounts of adsorbed AgNPs on the GO surface, made the electrochemical responses more sensitive; (2) thanks to the combined immune structure of Faradaycage-type, all AgNPs labeled on the detector unit could take part in the electrode reaction to emit signals. Under optimal conditions, the immunosensor exhibits a relatively wide linear range from 102 to 108 CFU mL−1 with a detection limit of 33 CFU mL−1. In addition, high selectivity and excellent recovery in seawater and seafood indicate that this immunosensor shows great prospect for practical application. Featured with high sensitivity, the proposed sensing scheme can thus offer new opportunities to achieve sensitive, selective, and simple detection of other bacteria.