SERS/EIS dual-channel aptamer sensor for accurate detection of aflatoxin B1

Surface Enhanced Raman Spectroscopy (SERS) and Electrochemical Impedance Spectroscopy (EIS) were combined in this work to develop a dual-channel aptamer-based biosensor platform for the detection of aflatoxin B1 (AFB1). The capture probe (Fe 3 O 4 @AuNFs@Aptamer) and the signal probe (AuNStar@4-MBA@Au@cDNA) were chemically synthesized step by step. During the process, SEM, TEM, XRD, Raman and UV-vis were applied to characterize these nanomaterials. The performance of the prepared biosensor was tested in AFB1 solutions. The results showed that the detection range of the SERS channel for AFB1 was 1×10 -4 to 1×10 2   ng/mL, with a limit of detection (LOD) of 7.83×10 -5   ng/mL and the average relative standard deviation (RSD) of the standard samples of 5.24%. And the EIS channel was 1×10 -4 to 1×10 2   ng/mL, with a LOD of 1.58×10 -4   ng/mL and the average RSD of the standard samples of 1.27%. These differences confirm that the combination of SERS/EIS technologies extends the detection limits and improves the reliability of this sensing platform. In summary, this strategy can be adapted to identify other target molecules simply by changing the aptamer, thereby providing a broad and universal platform for biosensing applications.