A novel SERS/electrochemical dual-channel aptasensor for the detection of aflatoxin (AFB1) in cereal foods

This study developed a novel SERS/electrochemical dual-channel aptasensor for the highly sensitive detection of Aflatoxin B1 (AFB 1 ). Firstly, Fe₃O₄@Au@Ag nanoparticles, synthesized by a seed-mediated growth method, were functionalized with AFB1 aptamers to serve as capture probes. Secondly，ssDNA (AFB 1 aptamer complementary chain) was modified on the AuNs@4-MBA@Ag surface for obtaining the signal probes. Then, the competitive biosensors were constructed based on competition between capture probe and AFB 1 . The sediment separated under neodymium magnet influence was employed for surface-enhanced Raman spectroscopy (SERS) testing, whilst the supernatant (dissociation signal probe) was placed upon a modified gold electrode for electrochemical analysis. The synthesized capture and signal probes were characterized through SEM, TEM, and XPS, thus confirming their successful synthesis. More importantly, the sample results showed that the detection limit (LOD) of this biosensor was 2 × 10 −6  ng/mL, the sample recovery rate was 91–117 %, which is sufficient for trace detection of AFB 1 .