Wang Mengyao, Xiao Chengui, Zhao Fengjuan, Suo Zhiguang, Liu Yong, Wei Min, Jin Baohui
College of Food Science and Technology, Henan Key Laboratory of Cereal and Oil Food Safety Inspection and Control, Henan University of Technology, Zhengzhou, 450001, PR China.
Food Inspection and Quarantine Technology Center of Shenzhen Customs, Shenzhen Academy of Inspection and Quarantine, Shenzhen, 518045, PR China.
Anal Chim Acta. 2025 Jan 15;1334:343424. doi: 10.1016/j.aca.2024.343424. Epub 2024 Nov 14.
Ochratoxin A (OTA) is a serious food contaminant, not easily degradable, and capable of causing irreversible damage to the human body. Therefore, it is of great practical significance to establish a sensitive and efficient OTA detection method. The electrochemical aptasensor has a broad development prospect in OTA detection with its advantages of fast response speed and low cost.
Herein, a cascade signal amplification strategy based on AuPt NPs/Zr-MOF and π-structure bipedal DNA walker-triggered hybridization chain reaction (HCR) was designed for the detection of ochratoxin A (OTA). AuPt NPs/Zr-MOF was employed as the electrode modification material, providing a large number of active sites and high conductivity, achieving 1.47 times signal amplification. Interestingly, bipedal DNA walker binds to hairpin 1 (H1) to form the π-structure. Under the activation of Pb, one bipedal DNA walker can simultaneously bind and cleave two H1. It exhibits a wide walking range and high recognition efficiency. After H1 is cleaved, the trigger sequence was exposed to trigger HCR and a large amount of methylene blue was loaded on the electrode. Under the optimal conditions, the linear range of the determined OTA is 1 × 10-500 ng/mL, and the limit of detection is as low as 0.525 pg/mL.
The experimental results demonstrate that the constructed electrochemical aptasensor is a sensitive and efficient platform for OTA monitoring. The applicability in food samples was also confirmed, and the strategy was efficiently selective and reproducible for different analytes. This provides ideas for subsequent food safety testing.
赭曲霉毒素A（OTA）是一种严重的食品污染物，不易降解，能够对人体造成不可逆的损害。因此，建立一种灵敏高效的OTA检测方法具有重要的现实意义。电化学适体传感器以其响应速度快、成本低等优点，在OTA检测方面具有广阔的发展前景。
本文设计了一种基于金铂纳米粒子/锆基金属有机框架（AuPt NPs/Zr-MOF）和π结构双足DNA步行器触发的杂交链式反应（HCR）的级联信号放大策略，用于检测赭曲霉毒素A（OTA）。采用AuPt NPs/Zr-MOF作为电极修饰材料，提供大量活性位点和高导电性，实现了1.47倍的信号放大。有趣的是，双足DNA步行器与发夹1（H1）结合形成π结构。在铅的激活下，一个双足DNA步行器可以同时结合并切割两个H1。它具有广泛的行走范围和高识别效率。H1被切割后，触发序列暴露以触发HCR，并在电极上负载大量亚甲基蓝。在最佳条件下，所测定的OTA的线性范围为1×10 - 500 ng/mL，检测限低至0.525 pg/mL。
实验结果表明，构建的电化学适体传感器是一种灵敏高效的OTA监测平台。还证实了其在食品样品中的适用性，该策略对不同分析物具有高效的选择性和重现性。这为后续食品安全检测提供了思路。
