In this study, the aptamer of ochratoxin A (OTA) increased the negative charge density on the surface of gold nanoparticles (AuNPs) and promoted the release of hydroxyl radicals and Au3+ to enhance the peroxidase-like activity of the AuNPs. The OTA bound only to the aptamer and did not adsorb non-specifically to the AuNPs. Based on these two conclusions, a label-free colorimetric aptasensor was successfully developed, enabling the precise detection of OTA within the concentration range of 10-600 nM, with a remarkably low detection limit of 6.20 nM. The colorimetric aptasensor was applied to detect OTA in oats, corn, soybeans, rice, and glutinous rice.

中文翻译：

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基于无标记适体和金纳米酶的检测赭曲霉毒素A的比色适体传感器。

本研究中，赭曲霉毒素A（OTA）适配体增加了金纳米颗粒（AuNPs）表面的负电荷密度，促进羟基自由基和Au3+的释放，从而增强AuNPs的类过氧化物酶活性。OTA 仅与适体结合，不会非特异性吸附到 AuNP。基于这两个结论，成功开发了一种免标记比色适体传感器，能够在10-600 nM浓度范围内精确检测OTA，检测限极低，为6.20 nM。应用比色适体传感器检测燕麦、玉米、大豆、大米和糯米中的OTA。