The residue of ampicillin (AMP) in food and ecological environment poses a potential harm to human health. Therefore, a reliable system for detecting AMP is in great demand. Herein, a label-free and sensitive electrochemical sensor utilizing NH–Co-MOF as an electrocatalytic active material for methylene blue (MB) was developed for rapid and facile AMP detection by combining hybridization chain reaction (HCR), catalytic hairpin assembly (CHA) with CRISPR/Cas12a. The surface of glassy carbon electrode modified with NH–Co-MOF was able to undergo HCR independent of the AMP, forming long dsDNA complexes to load MB, resulting in strong original electrochemical signal. The presence of AMP could trigger upstream CHA circuit to activate the CRISPR/Cas12a system, thereby achieving rapid non-specific cleavage of the trigger ssDNA of HCR on the electrode surface, hindering the occurrence of HCR and reducing the load of MB. Significant signal change triggered by the target was ultimately obtained, thus achieving sensitive detection of the AMP with a detection limit as low as 1.60 pM (S/N = 3). The proposed sensor exhibited good stability, selectivity, and stability, and achieved reliable detection of AMP in milk and livestock wastewater samples, demonstrating its promising application prospects in food safety and environmental monitoring.

中文翻译：

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将核酸等温无酶扩增电路与 CRISPR/Cas12a 相结合，用于灵敏检测氨苄青霉素的无标记电化学传感平台

氨苄青霉素（AMP）在食品和生态环境中的残留对人体健康构成潜在危害。因此，迫切需要一种可靠的 AMP 检测系统。在此，通过结合杂交链式反应（HCR）、催化发夹组装（CHA），开发了一种利用 NH-Co-MOF 作为亚甲基蓝（MB）电催化活性材料的无标记且灵敏的电化学传感器，用于快速简便的 AMP 检测使用 CRISPR/Cas12a。用NH-Co-MOF修饰的玻碳电极表面能够独立于AMP进行HCR，形成长的dsDNA复合物来负载MB，从而产生强烈的原始电化学信号。 AMP的存在可以触发上游CHA电路激活CRISPR/Cas12a系统，从而实现电极表面HCR触发ssDNA的快速非特异性切割，阻碍HCR的发生并减少MB的负载。最终获得了目标物触发的显着信号变化，从而实现了AMP的灵敏检测，检测限低至1.60 pM（S/N = 3）。该传感器表现出良好的稳定性、选择性和稳定性，实现了牛奶和畜牧废水样品中AMP的可靠检测，展示了其在食品安全和环境监测方面的广阔应用前景。