Abstract：
Ochratoxin A (OTA) in food poses a serious challenge to public health. Herein, using the nanobody-driven controllable aggregation of gold nanoparticles (AuNPs) in a glucose oxidase-tyramine-horseradish peroxidase (GOx-TYR-HRP) system, we propose a direct competitive plasmonic enzyme immunoassay (dc-PEIA) for OTA detection. The OTA-GOx conjugate catalyzes glucose to produce hydrogen peroxide (H2O2), and then HRP catalyzes H2O2 to generate hydroxyl radical which induces the crosslink of TYR. Crosslinked TYR leads to aggregation of AuNPs through strong electrostatic interactions, which is tunable based on the competition of OTA-GOx and free OTA for binding the immobilized nanobody. The optimized dc-PEIA achieves an instrumental limit of detection (LOD) of 0.275 ng/mL and a visual LOD of 1.56 ng/mL. It exhibits good selectivity for OTA and accuracy in the analysis of pepper samples, with the confirmation of high-performance liquid chromatography. Overall, the dc-PEIA is demonstrated as a useful tool for detecting OTA in food.
摘要：
食品中的曲霉毒素A（OTA）对公共卫生构成了严峻的挑战。在这里，在葡萄糖氧化酶-酪胺-辣根过氧化物酶（GOx-TYR-HRP）系统中使用纳米体驱动的金纳米颗粒（AuNPs）的可控聚集，我们提出了一种用于OTA检测的直接竞争等离子体酶免疫测定法（dc-PEIA）。OTA-GOx共轭物催化葡萄糖产生过氧化氢(H2O2),然后HRP催化H2O2产生羟基自由基，诱导TYR的交联。交联的TYR通过强的静电相互作用导致AuNP的聚集，基于OTA-GOx和游离OTA结合固定化纳米抗体的竞争是可调的。优化的dc-PEIA实现了0.275ng/mL的仪器检测限（LOD）和1.56ng/mL的视觉LOD。它对OTA具有良好的选择性和辣椒样品分析的准确性，与高效液相色谱的确认。总的来说,dc-PEIA被证明是检测食品中OTA的有用工具。
