A Reagentless Aptamer Sensor Based on a Self-Powered DNA Machine for Electrochemical Detection of AFB1

Here, we developed a novel reagentless aptamer sensor for the detection of aflatoxin B1 (AFB1) that uses a DNA walker strategy and bisferrocene to enhance the signal. First, the special binding of AFB1 and AFB1 aptamer activates the DNAzyme strand. Then, with the aid of Mn 2+ , the DNAzyme strand sequentially cuts the bisferrocene immobilized substrate strand, resulting in a change in the electrochemical signal. And we wrapped Mn 2+ in the organometallic framework UiO-66(Zr)-(COOH) 2 and integrated it with DNA walker. It enables the initiation of the cut reaction without the addition of Mn 2+ during the detection, enabling real-time monitoring. Based on the above advantages, under optimal conditions, the sensor shows good detection linearity in the range of 0.1 pg/mL to 1000 ng/mL, and the detection limit is 4.81 fg/mL. The sensor has also been successfully applied for the detection of AFB1 in complex matrices, including peanut oil samples, with high sensitivity and reagentless operation. In addition, the proposed aptamer sensor can be used to detect other mycotoxins by replacing the aptamer, thus providing an efficient platform for the detection and real-time monitoring applications. Graphical Abstract A reagentless electrochemical aptamer sensor for AFB1 detection was constructed based on DNAzyme-driven DNA walker and bisferrocene. No significant change in electrochemical signal was observed when the target AFB1 was not added. The electrochemical signal was significantly reduced when the target AFB1 was added.