Boron-doped diamond electrochemical aptasensors for trace aflatoxin B₁ detection

An electrochemical aptasensor for detecting trace aflatoxin B₁ (AFB₁) 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 AFB₁ concentration, the low detection limit (wide linear relationship range) of the aptasensor is realized to be 5.5 × 10^-14 mol L^-1 (1.0 × 10^-13‒1.0 × 10^-8 mol L^-1). The variation in impedance property of the aptasensor is determined by the specific adsorption of AFB₁ 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 AFB₁ 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 AFB₁ in environments.