A facile and effective electrochemical immunosensor based on controlled and oriented immobilization of natural antibodies for sensitive detection of aflatoxin B1.

Aflatoxin B1 (AFB1) is one of the most common and harmful toxins in agricultural products, and the development of a sensitive, simple, and accurate detection method for AFB1 is crucial for ensuring continuous monitoring and safeguarding food safety. Herein, we describe a facile and effective electrochemical immunosensor for ultrasensitive detection of AFB1. In this framework, a novel Fc-specific cysteine (Cys)-modified antibody was first fabricated by employing photoaffinity labeling technique, which enables antibodies to be directionally immobilized onto a bare gold electrode via Au-sulfhydryl interaction. The proposed immunosensor exhibited detection limits (LODs) of 0.054 and 0.019 ng mL-1 for direct competitive and sandwich-type competitive assays, respectively. Notably, these LODs were approximately 8-fold and 10-fold lower, respectively, compared to those achieved with randomly immobilized antibodies. The proposed immunosensor demonstrated excellent stability and reproducibility, along with high sensitivity, accuracy, and precision in AFB1 detection, suggesting its significant potential for applications in food safety applications.