Boron-doped diamond electrochemical aptasensors for trace aflatoxin B detection.

An electrochemical aptasensor for detecting trace aflatoxin B (AFB) is designed and fabricated consisting of aptamers and gold nanoparticles on conductive boron-doped diamond (BDD) electrode. By examining the relative impedance shift from electrochemical impedance spectroscopy as a function of AFB concentration, the low detection limit (wide linear relationship range) of the aptasensor is realized to be 5.5 × 10 mol L (1.0 × 10‒1.0 × 10 mol L). The variation in impedance property of the aptasensor is determined by the specific adsorption of AFB molecules to the aptamer at a certain concentration covering the electrode. By means of multiple characteristic processes, it is demonstrated that the constructed aptasensor is favorable for testing the trace AFB with high specificity, sensitivity, stability, repeatability, and reusability, which lead to a possibility to achieve high performance biosensor for practical application to quantitatively detract trace AFB in environments.