An Antibody Ordered Assembly Functional BPE-ECL Platform for Aflatoxin B1 Detection

Due to the complex characteristics of food matrix, false positives may occur when using traditional methods to detect aflatoxin B1 (AFB1). In this paper, we utilize the advantages of closed bipolar electrode (BPE) that can effectively avoid the impact of complex food matrices on signal collection, and design a biosensor based on immune competition to detect highly toxic AFB1. The biosensor uses cathode of closed BPE as a functional sensing interface and anode as a signal collection interface. On the functional sensing interface, AFB1 connects to the monoclonal antibody at the top of DNA tetrahedron structure. Under the action of horseradish peroxidase (HRP), 4-chloro-1-naphthol (4-CN) is catalyzed by hydrogen peroxide (H 2 O 2 ) to generate precipitations (4-CD). AFB1 competes with HRP-AFB1 to bind monoclonal antibody, resulting in a decrease in the content of HRP involved in catalytic oxidation reactions and a synchronous reduction in precipitations produced, causing an increase in the intensity of [Ru(bpy) 3 ] 2+ /TPA system electrochemiluminescence (ECL) on the BPE anode. Analysis shows that the relative deviation between the detection results and ELISA is between −4.5 and 9.8%, and there is no significant difference in the performance of the two in detecting AFB1. The BPE-ECL sensor exhibits high sensitivity and specificity in detecting AFB1, with a linear range of 0.01–40 ng mL −1 and a detection limit of 3 pg mL −1 . In the future, it can be applied to the detection of other toxins, with broad application prospects.