Electrochemical immunosensor based on antibody-oriented probe for the detection of AFB1 in rice bran oil

Aflatoxin B1 is one of the most toxic mycotoxins, posing a serious threat to human health. There is an urgent need to develop sensitive, rapid and selective ways for the detection of AFB1. Herein, an electrochemical immunosensor was fabricated using the antibody-oriented probe (gold nanoparticle-Streptococcal protein A-anti-AFB1 monoclonal antibody, AuNP-SPA-mAb) to analyze AFB1 in rice bran oil. AuNP-SPA-mAb probe was constructed by the introduction of streptococcal protein A to ensure the controlled immobilization of antibody. AFB1 competed with antigen loaded on the gold electrode for binding AuNP-SPA-mAb in the presence of the target AFB1, inhibiting the capture of horse radish peroxidase (HRP)-labeled second antibody. Subsequently, HRP could facilitate the oxidization of hydroquinone in the presence of hydrogen peroxide, resulting in the production of an electrochemical signal. Under optimal conditions, this immunosensor displayed a linear range of 10-8000 pg/mL and a limit of detection of 2.2 pg/mL. The fabricated immunosensor was further utilized to verify the potential application by detecting samples of rice bran oil. Recovery rates varied from 88.0% to 107.9%. This immunosensor provides a highly sensitive and rapid approach for the determination of such mycotoxins.