基于核酸适配体-聚多巴胺纳米复合物的荧光生物传感器检测赭曲霉素A

Aptamer/Polydopamine Nanospheres Complex Based Fluorescence Biosensor for Sensitive and Selective Detection of Ochratoxin A

基于聚多巴胺纳米颗粒(PDANPs)高的荧光猝灭效率,以及核酸适配体特异性的识别能力,构建了一种快速、简便、灵敏且经济实用的荧光生物传感器,并用于赭曲霉素A(OTA)的检测。标记有荧光团(Carboxyfluorescein,FAM)的核酸适配体可通过π-π堆积作用吸附于PDANPs表面,使FAM的荧光猝灭。加入OTA后,OTA与核酸适配体特异性结合,使核酸适配体从单链状态折叠为稳定的G-四链体结构。由于G-四链体与PDANPs之间的结合能力弱,导致传感体系的荧光信号增强,从而实现了OTA的定量测定,其检出限为20nmol/L。此外,该方法还可用于红酒中OTA的测定,回收率为96%~105%。

In this work,based on the high fluorescence quenching efficiency of polydopamine nanospheres(PDANPs)and the specific recognition capability of aptamer,we constructed a rapid,simple,sensitive and economical fluorescence biosensor for'turn-on'detection of ochratoxin A(OTA).In the absence of OTA,the fluorescence of 6-carboxyfluorescein(FAM,labeled at 5′end of aptamer)was readily quenched due to the strong binding between OTA-aptamer and PDANPs.In the presence of OTA,the conformation of the OTA-specific aptamer changed from a random-coil to an antiparallel G-quadruplex,which resulted in the dissociation of the FAM from the surface of PDANPs and the increasing of fluorescence intensity.The pH value of 8.5 and a concentration of PDANPs at 0.3 mg/mL were chosen as the optimal assay conditions for OTA experiments.This method allowed quantitative detection of OTA with a detection limit of 20 nmol/L under the optimum conditions.Furthermore,it was applied for the detection of OTA in red wine and the recovery in the range of 96%-105%was obtained.