A Faraday cage-type immunosensor for dual-modal detection of Vibrio parahaemolyticus by electrochemiluminescence and anodic stripping voltammetry

Highlights: • OHP-extended Faraday cage-type immunosensor was developed for the detection of VP. • A novel dual-modal and low false-positive system by ECL and ASV was presented. • Detector unit Ru-AgNPs@GO-dAb generating ECL and ASV signals was fabricated. • This strategy provided a new perspective for the detection of pathogenic bacteria. -- Abstract: Vibrio parahaemolyticus (VP), as a kind of harmful bacterium to human beings, its rapid and accurate detection is particularly important. Herein, we developed a simple and efficient dual-modal Faraday cage-type immunosensor for ultrasensitive detection of VP based on electrochemiluminescence (ECL) and anodic stripping voltammetry (ASV). After being captured by capture unit on magnetic glassy carbon electrodes, VP was recognized by detector unit, achieving ECL and ASV dual-modal detection. Compared with traditional sandwich-type immunosensors, this proposed immunosensor has the advantages of significant signal amplification effects, due to its distinctive Faraday cage-type structure. Benefited from it, all Ru(bpy)₂²⁺ and AgNPs labeled on the detector unit could participate in the electrode reaction and generate stronger ECL and electrochemical signals respectively. Under the optimized conditions, the linear range was from 10² to 10⁷ CFU mL⁻¹ with a limit of detection (LOD) of 33 CFU mL⁻¹, and the selectivity, stability and reproducibility were satisfactory. In addition, the results of two detection methods can mutually validate each other to avoid false positive results. Moreover, this Faraday cage-type immunosensor with dual-modal detection can also be used for detection of VP in seawater samples with recoveries in the range of 96.1–107.9%, which would be a promising tool for pathogenic bacteria analysis.