Au nanopartics decorated urchin-like Bi2S3 on graphene wrapped carbon fiber microelectrode: Towards electrochemical immunosensor for sensitive determination of aflatoxin B1

Aflatoxin in food is a significant concern that threatens human health and life and causes a heavy burden on international trade and healthcare. In this work, we developed a new type of label-free electrochemical immunosensor for the high-sensitivity determination of aflatoxin B1 (AFB1) based on Au nanoparticles decorated urchin-like Bi2S3 (Au/Bi2S3) anchored on electrochemically reduced graphene oxide (ERGO) modified carbon fiber (CF) microelectrode (Au/Bi2S3/ERGO/CF). The morphology and characterization of the modified microelectrode were investigated using scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). Under the optimum conditions, the label-free electrochemical immunosensor detected AFB1 within the linear range of 10 pg mL−1 to 20 ng mL−1, with a low detection limit of 8 pg mL−1 and high sensitivity (0.48 μA/ng mL). The immunosensor showed high selectivity, good reproducibility, and acceptable stability. The immunosensor was applied to detecting AFB1 in cornflour samples, offering excellent reliability and accuracy compared with typical detection methods. Finally, this platform provides a superior prospect for the development of a nanohybrid immunosensor.