Detection of AFB1 in corn by MXene paper-based unlabeled aptasensor

In this work, a paper-based electrochemical aptamer sensor was developed for the detection of aflatoxin B1 (AFB1) using a combination of MXene–Ti 3 C 2 T x and nucleic acid aptamers. The prepared single-layer or few-layer MXene suspension is suction-filtered onto MXene paper, which is cut to prepare MXene electrodes. To accomplish AFB1 specific detection, an amino-labeled AFB1 aptamer is mounted on the surface of the carboxy-functionalized MXene electrode. When AFB1 is present, it particularly binds to the aptamer to form a 3D structure, reducing the efficiency of electron transmission on the sensor surface. The difference in impedance signal change at the electrode/electrolyte interface is used to quantify AFB1. The results indicated that the detection range is 0.05–100 ng/mL, the detection limit is 0.04 ng/mL, and the recovery rate of AFB1 in corn samples is 97.8%–111.52% with the optimal detection conditions. The MXene paper-based label-free aptasensor is versatile and can detect different targets by simply swapping out the aptamers of different targets. The sensor also has a wide range of applications in food analysis and environmental testing. Practical applications A paper-based electrochemical aptamer sensor was developed to detect aflatoxin B1 using a combination of MXene–Ti 3 C 2 T x and nucleic acid aptamers.The design is based on the preparation of MXene electrodes by pumping and filtering monolayer or multilayer MXene suspensions onto MXene paper and cutting.The MXene paper-based label-free aptamer sensor was designed to be versatile, allowing the detection of different targets by simply replacing the aptamer with one from a different targets.