Enhancement of aflatoxin B1 detection using electrochemical immunoassay method and 2-aminoethanethiol

Abstract

The detection of aflatoxin B1 (AFB1) using immunoassays, especially electrochemical immunoassays, is fast, sensitive and efficient. In this study, 2-aminoethanethiol was used to enhance the speed and sensitivity of conventional electrochemical immunoassays for AFB1 detection by assembly on the surface of a Au electrode, forming self-assembled monolayers (SAMs). Then, non-competitive immunoassays occurred on the modified electrode surface forming an electrochemical immunoassay sensor. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy were used to examine the state of the SAMs, and an electrochemical workstation was used to monitor the current change of the electrochemical reaction, so as to characterize the designed immunosensor. Our experimental results shows that, the 2-aminoethanethiol reagent was successfully assembled on the Au surface through Au-S bonding and the –NH2 terminal group faced outward. Herein, the minimum concentration of AFB1 which caused a significant current change was 0.01 ng/mL. The prepared immunosensor also exhibited excellent stability and sensitivity after storage for 7 days or upon regeneration.