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 Mn²⁺, the DNAzyme strand sequentially cuts the bisferrocene immobilized substrate strand, resulting in a change in the electrochemical signal. And we wrapped Mn²⁺ 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 Mn²⁺ 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.

中文翻译：

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基于自供电 DNA 机器的无试剂适体传感器用于 AFB1 的电化学检测

在这里，我们开发了一种用于检测黄曲霉毒素 B1 (AFB1) 的新型无试剂适体传感器，它使用 DNA 步行者策略和二茂铁来增强信号。首先，AFB1 和 AFB1 适体的特殊结合激活了 DNAzyme 链。^{然后，在 Mn 2+}的帮助下，DNAzyme 链依次切割双茂铁固定的底物链，导致电化学信号发生变化。我们将 Mn ²⁺包裹在有机金属框架 UiO-66(Zr)-(COOH) ₂中，并将其与 DNA walker 集成。^{它可以在不添加 Mn 2+}的情况下引发切割反应在检测过程中，实现实时监控。基于以上优点，在最佳条件下，该传感器在0.1 pg/mL至1000 ng/mL范围内表现出良好的检测线性，检测限为4.81 fg/mL。该传感器还成功应用于复杂基质（包括花生油样品）中 AFB1 的检测，具有高灵敏度和无试剂操作。此外，所提出的适体传感器可通过替代适体来检测其他霉菌毒素，从而为检测和实时监测应用提供了一个高效的平台。

图形概要

基于 DNAzyme 驱动的 DNA 步行者和二茂铁构建了用于 AFB1 检测的无试剂电化学适体传感器。当未添加目标 AFB1 时，未观察到电化学信号的显着变化。当添加目标 AFB1 时，电化学信号显着降低。