构建电化学适配体生物传感检测薏苡仁和白扁豆中赭曲霉毒素A的研究

Study on Electrochemical Aptasensor for Detecting Ochratoxin A in Semen Coicis and Semen Lablab Album

目的构建一种电化学适配体传感检测方法用于薏苡仁和白扁豆中赭曲霉毒素A(OTA)的高灵敏检测,为中药质量控制和用药安全提供新思路。方法采用一步电沉积法制备电化学还原氧化石墨烯(ErGO)和纳米金(NG)衬底的玻碳电极,通过π-π堆叠作用将标记有亚甲基蓝(MB)的单链OTA适配体吸附在电极表面,OTA与适配体结合并使其脱离电极表面,导致MB信号电流发生改变,根据峰电流变化实现对OTA的定量检测。结果在0.05~10 ng/mL的浓度范围内,峰电流值(I_(p))与OTA浓度的对数具有良好的线性关系,相关系数r=0.9938,检测限(3σ/S)为0.03 ng/mL,该方法用于中药饮片薏苡仁和白扁豆中OTA的加标回收测定,加标回收率为92.94%~105.17%,相对标准偏差(RSD)≤5.60%。结论该方法灵敏度高,选择性好,且经济便捷,操作简单,有望用于中药材中OTA污染的现场快速检测。

Objective:To construct an electrochemical aptasensor for detecting ochratoxin A(OTA)in Semen coicis and Semen lablab album,and to provide a new idea for quality control and drug safety of traditional Chinese medicine.Methods:A glassy carbon electrode modified with electrochemically reduced graphene oxide(ErGO)and nano gold(NG)substrates was prepared by onestep electrodeposition.The single-strand OTA aptamers labeled with methylene blue(MB)were adsorbed on the electrode surface throughπ-πstacking.OTA combined with the aptamers and separated it from the electrode surface,resulting in the change of MB signal current to realize quantitative detection of OTA.Results:In the range of 0.05-10 ng/mL,the peak current(Ip)had a good linear relationship with the logarithm of OTA concentration,the correlation coefficient(r)was 0.9938,and the detection limit(3σ/S)was 0.03 ng/mL.The method was applied to the determination of OTA in Semen coicis and Semen lablab album,the recoveries were 92.94%-105.17%,and the relative standard deviation(RSD)was less than 5.60%.Conclusion:The method is easy to operate and has good selectivity and high stability.It is expected to be used for the rapid detection of OTA in traditional Chinese medicine.