Novel Electrochemical Immunosensor for Aflatoxin B1 Detection Utilizing Dual Nanoparticles for Dual-Signal Amplification

A novel electrochemical immunosensor has been proposed for rapid determination of Aflatoxin B1 (AFB1). To improve sensitivity, a nanocomposite of AgNPs, ZIF-90, and MWCNTs was integrated for the first time as the electrode modification material, creating a dual-signal amplification strategy. Compared with previously reported sensors that typically employ one or two of these components, this design simultaneously addresses the conductivity limitation of ZIF-90 and the aggregation tendency of MWCNTs, providing a notable advancement in sensitivity. Characterization of the nanocomposite was carried out using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FT-IR). The sensitivity and specificity of the sensor are optimized to achieve reliable trace detection of AFB1, even at low concentrations relevant to safety standards. Under optimal conditions, the proposed immunosensor achieved a quantitative detection limit of 0.05 ng/mL for AFB1, which greatly exceeds the sensitivity of traditional methods and can effectively detect within a wide detection range (0.05–1000 ng/mL). In actual sample analysis, the recovery rate ranges from 93.90 to 102.15%, which is consistent with the HPLC results. Therefore, immunosensors may be a promising tool for determining AFB1.