A ratiometry-induced successive reusable electrochemical aptasensing platform: Efficient monitoring of aflatoxin B1 in peanut

Abstract

• The successive reusable electrochemical method was achieved on the basis of ratiometric strategy. • A reusable electrochemical assay was developed for successive detection of AFB1 in peanut. • The aptasensor showed enhanced analytical properties compared with sensors based on single-signal response mode. Currently, most reusable aptasensors rely on the reassembly of aptamers to regenerate the sensing interface. However, it remains challenging to achieve successive aptasensor reusability. Herein, for the first time, we demonstrate that a ratiometric strategy endows the electrochemical aptasensor high reusability to realize the successive detection of aflatoxin B1 (AFB1). The model sensing interface used thionine (THI)-graphene nanocomposite and ferrocene (Fc)-labeled aptamer to output current signals (I THI and I Fc ). For analysis, the specific recognition of AFB1 by aptamers caused it to strip from the electrode, and the value of I THI /I Fc varied linearly with AFB1 concentration over the 0.01−100 ng mL −1 range. This relationship also worked when using a single sensor for multiple successive testing but completely failed with I THI or I Fc alone. This unique successive reusability was ascribed to the ratiometric strategy capable of eliminating the environmental influence on both signals. The feasibility of the proposed aptasensor was validated by applying it to the successive detection of AFB1, which showed excellent accuracy and reliability compared with the official method, i.e., standard high-performance liquid chromatography-fluorescence (HPLC-FL). This successive reusable electrochemical aptasensing platform can be universal for advanced analysis, and it promotes the practical applications of aptasensors particularly in the field of rapid assays.