Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, China.
Luminescence. 2023 Sep;38(9):1678-1685. doi: 10.1002/bio.4556. Epub 2023 Jul 28.
Ochratoxin A (OTA) is a toxic metabolite commonly found in various foods and feedstuffs. Accurate and sensitive detection of OTA is needed for food safety and human health. Based on a common OTA-binding aptamer (OTABA), two structure-switching OTABAs, namely OTABA4 and OTABA3, were designed by configuring a split G-quadruplex and a split G-triplex, respectively, at the two ends of OTABA to construct aptasensors for the detection of OTA. The OTABA, G-quadruplex, and G-triplex all can capture the thioflavin T (ThT) probe, thereby enhancing the fluorescence intensity of ThT. Bonding with OTA could change the conformations of OTABA and G-quadruplex or G-triplex regions, resulting in the release of the captured ThT and diminution of its fluorescence intensity. Dual conformation changes in structure-switching OTABA synergistically amplified the fluorescence signal and improved the sensitivity of the aptasensor, especially for that with OTABA3. The detection limits of the OTABA4-ThT and OTABA3-ThT systems for OTA were 0.28 and 0.059 ng ml , with a 1.4-fold and 6.7-fold higher sensitivity than that of the original OTABA-ThT system, respectively. They performed well in corn and peanut samples and met the requirements of the food safety inspections.
赭曲霉毒素 A（OTA）是一种常见于各种食品和饲料中的有毒代谢物。为了食品安全和人类健康，需要准确和灵敏地检测 OTA。基于常见的 OTA 结合适体（OTABA），通过在 OTABA 的两端分别配置分裂 G-四链体和分裂 G-三链体，设计了两种结构切换的 OTABAs，即 OTABA4 和 OTABA3，以构建用于检测 OTA 的适体传感器。OTABA、G-四链体和 G-三链体都可以捕获硫黄素 T（ThT）探针，从而增强 ThT 的荧光强度。与 OTA 结合可以改变 OTABA 和 G-四链体或 G-三链体区域的构象，导致捕获的 ThT 释放并减弱其荧光强度。结构切换适体中的双重构象变化协同放大了荧光信号，提高了适体传感器的灵敏度，特别是对于 OTABA3。OTABA4-ThT 和 OTABA3-ThT 系统对 OTA 的检测限分别为 0.28 和 0.059ngml，比原始 OTABA-ThT 系统的灵敏度分别提高了 1.4 倍和 6.7 倍。它们在玉米和花生样品中的表现良好，符合食品安全检测的要求。
