Electrochemiluminescent aptasensor for aflatoxin B1 by integrating anodized aluminum oxide for nanopore screening and gold nanoparticles for surface plasmon resonance amplification

Protecting cereals from contamination by mycotoxins requires rapid and sensitive detection methods. In this study, a screening-detection electrochemiluminescent (ECL) aptasensor was constructed by combining Ru(bpy)32+-doped silica nanoparticles (RuSiNPs) and anodized aluminum oxide (AAO). This aptasensor was successfully used in the ultrasensitive and highly selective detection of aflatoxin B1 (AFB1) in wheat. In the aptasensor, MXene and gold nanoparticles (AuNPs) act as the conductive material and surface plasmon resonance (SPR) source, respectively, to enhance the ECL signals of RuSiNPs. Meanwhile, due to their highly ordered porous structure, AAO pasted on the electrode surface can effectively screen out the macromolecular interferents, providing a pure environment for the aptamer (Apt) to specifically capture AFB1. Because the formed AFB1-Apt complex hinders electron transfer, the ECL intensity of the aptasensor decreases with increasing AFB1 concentration to achieve quantitative detection. Under the optimal conditions, the linear range and detection limit of the screening-detection ECL aptasensor were 0.01−100 μg/kg and 1.5 × 10−3 μg/kg (S/N = 3), respectively. In summary, the proposed screening-detection ECL aptasensor for the quantitative detection of AFB1 is a promising new approach for the early detection of moldy wheat.