State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.
State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China.
Talanta. 2024 Apr 1;270:125636. doi: 10.1016/j.talanta.2024.125636. Epub 2024 Jan 6.
Shiga toxin type II (Stx2), the major virulence component of enterohemorrhagic Escherichia coli, is strongly associated with the life-threatening hemolytic uremic syndrome thus posing a substantial risk to food safety and human health. In this work, a dual-mode aptasensor with colorimetric and surface-enhanced Raman scattering was developed for Stx2 specific detection based on noble metal nanoparticles and Raman reporter loaded metal-organic framework (Mn/Fe-MIL(53)@AuNSs-MBA). The Mn/Fe-MIL(53)@AuNSs could catalyze the HO-mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), thereby enabling visual detection. Meanwhile, the SERS signal from MBA can be enhanced by the decorated AuNSs. Under optimal conditions, a linear range of 0.05-500 ng/mL with limit of detection (LOD) of 26 pg/mL was achieved in colorimetric mode and a linear range of 5-1000 ng/mL with LOD of 0.82 ng/mL in SERS mode, in which the dual-mode results complement each other, widening the linear range, increasing the accuracy and reliability of the detection. The method was further applied to the detection of Stx2 in milk with average recovery of 101.1 %, demonstrating its superior potential for bacterial toxin monitoring.
志贺毒素 2 型（Stx2）是肠出血性大肠杆菌的主要毒力成分，与危及生命的溶血性尿毒症综合征密切相关，因此对食品安全和人类健康构成了重大风险。在这项工作中，基于贵金属纳米粒子和负载有拉曼报告分子的金属有机骨架（Mn/Fe-MIL(53)@AuNSs-MBA），开发了一种用于 Stx2 特异性检测的双模式适体传感器，具有比色和表面增强拉曼散射功能。Mn/Fe-MIL(53)@AuNSs 可以催化 HO 介导的 3,3',5,5'-四甲基联苯胺（TMB）的氧化，从而实现可视化检测。同时，MBA 的 SERS 信号可以被修饰的 AuNSs 增强。在最佳条件下，比色模式的线性范围为 0.05-500ng/mL，检出限（LOD）为 26pg/mL；SERS 模式的线性范围为 5-1000ng/mL，LOD 为 0.82ng/mL。两种模式相互补充，拓宽了线性范围，提高了检测的准确性和可靠性。该方法进一步应用于牛奶中 Stx2 的检测，平均回收率为 101.1%，显示出其在细菌毒素监测方面的巨大潜力。
