College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming, 650500, P. R. China.
Analyst. 2022 Oct 10;147(20):4578-4586. doi: 10.1039/d2an00934j.
Ochratoxin A (OTA) is a highly toxic food contaminant and is harmful to human beings. Herein, a ratiometric electrochemical aptasensor based on a DNA tetrahedral nanomaterial (NTH) was developed in combination with the signal tag of a zirconium metal-organic framework (UiO-66) for the detection of OTA. In the sensor, UiO-66 and a [Fe(CN)] electrolyte solution were used as the signal probe and the internal reference probe, respectively. In the presence of OTA, the OTA aptamer was released from the electrode due to the specific binding of OTA. Thus, signal probe P1 labeled-UiO-66 was captured on the electrode surface by hybridization with DNA NTH. Since signal probe P1 labeled-UiO-66 was close to the electrode, it leads to an increased signal current of UiO-66 at +0.9 V. As the conductivity of the modified electrode decreased, the current signal of [Fe(CN)] at +0.2 V also decreased. The proposed ratiometric electrochemical aptasensor could effectively eliminate external environmental influences and could avoid electrochemical background signals. The aptasensor demonstrated high specificity for OTA, and achieved a good linear range of 1 pg mL-100 ng mL with a detection limit of 330 fg mL. The developed electrochemical aptamer biosensor effectively detected OTA in corn kernel samples, verifying its practical application for the determination of OTA in actual samples.
赭曲霉毒素 A（OTA）是一种高毒性的食品污染物，对人类有害。在此，结合锆基金属有机骨架（UiO-66）的信号标签，开发了一种基于 DNA 四面体形纳米材料（NTH）的比率型电化学适体传感器，用于检测 OTA。在传感器中，UiO-66 和 [Fe(CN)] 电解质溶液分别用作信号探针和内参探针。在 OTA 的存在下，由于 OTA 的特异性结合，OTA 适体从电极上释放出来。因此，通过与 DNA NTH 杂交，标记有 P1 的信号探针 UiO-66 被捕获在电极表面上。由于信号探针 P1 标记-UiO-66 靠近电极，导致+0.9 V 处 UiO-66 的信号电流增加。由于修饰电极的电导率降低，[Fe(CN)] 在+0.2 V 处的电流信号也降低。所提出的比率型电化学适体传感器可以有效地消除外部环境影响，并避免电化学背景信号。该适体传感器对 OTA 具有高特异性，在 1 pg mL-100 ng mL 的线性范围内具有良好的检测限为 330 fg mL。开发的电化学适体生物传感器有效地检测了玉米籽粒样品中的 OTA，验证了其在实际样品中检测 OTA 的实际应用。
