Ochratoxin A (OTA) is the most toxic class of ochratoxins and has become a major threat to the environment, humans and animals. Therefore, research on the methods for its detection is also more urgent. Herein, we propose a low-background electrochemical biosensor based on a DNA tetrahedron-besieged primer and a DNAzyme-activated programmatic rolling circle amplification (RCA) that can be ultimately utilized for OTA detection in wine samples. Low-background detection can be achieved using the besieged primer via sequenced assembly of DNA tetrahedral nanostructures so that non-specific extensions of primer can be avoided. The target OTA-mediated DNAzyme activation initiates the programmatic RCA. Additionally, the catalytic property of silver nanoclusters (AgNCs) is integrated with the electrochemical assay to achieve high sensitivity for OTA detection. Benefiting from the aforementioned processes, a low-background, and highly sensitive electrochemical biosensor has been successfully constructed. This design is capable of detecting OTA at concentrations from 1 pg/mL to 10 ng/mL, and its lowest concentration limit is 0.773 pg/mL. Simultaneously, its validation in the detection of actual samples reveals that the proposed electrochemical biosensor has a lot of potential in food safety and environmental detection.

赭曲霉毒素 A (OTA) 是赭曲霉毒素中毒性最强的一类，已成为对环境、人类和动物的主要威胁。因此对其检测方法的研究也更为迫切。在此，我们提出了一种基于 DNA 四面体包围引物和 DNAzyme 激活的程序化滚环扩增 (RCA) 的低背景电化学生物传感器，最终可用于葡萄酒样品中的 OTA 检测。低背景检测可以使用围困引物通过 DNA 四面体纳米结构的顺序组装来实现，从而可以避免引物的非特异性延伸。目标 OTA 介导的 DNAzyme 激活启动程序性 RCA。此外，银纳米团簇 (AgNCs) 的催化特性与电化学分析相结合，可实现 OTA 检测的高灵敏度。得益于上述过程，成功构建了低本底、高灵敏度的电化学生物传感器。该设计能够检测浓度为 1 pg/mL 至 10 ng/mL 的 OTA，其最低浓度限值为 0.773 pg/mL。同时，其在实际样品检测中的验证表明，所提出的电化学生物传感器在食品安全和环境检测方面具有很大的潜力。最低浓度限值为 0.773 pg/mL。同时，其在实际样品检测中的验证表明，所提出的电化学生物传感器在食品安全和环境检测方面具有很大的潜力。最低浓度限值为 0.773 pg/mL。同时，其在实际样品检测中的验证表明，所提出的电化学生物传感器在食品安全和环境检测方面具有很大的潜力。