Hu Yang, Xie Hanyin, Hu Jiaying, Yang Danting
Department of Preventative Medicine, Zhejiang Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, 818 Fenghua Road, Ningbo 315211, China.
Micromachines (Basel). 2022 May 26;13(6):834. doi: 10.3390/mi13060834.
Signal amplification is crucial in developing a reliable disposable screen-printed carbon electrodes (SPCEs)-based biosensor for analyte detection with a narrow detection window. This work demonstrated a novel label-free electrochemical aptasensor based on SPCEs for the ultrasensitive detection of ochratoxin A (OTA). The graphene oxide-DNA (GO-DNA) complex as a signal amplifier with easy preparation was investigated for the first time. The proposed aptasensor based on the SPCEs/GO/cDNA-aptamer/3D-rGO-AuNPs structure was formed through the hybridization of aptamer-linked 3D-rGO/AuNPs and its complementary DNA-linked GO (GO-cDNA). The presence of OTA was discerned by its specific aptamer forming a curled OTA-aptamer complex and releasing the GO-cDNA from the surface of SPCEs. The resulting OTA-aptamer complex hindered interfacial electron transfer on the sensing surface, leading to the decreased peak current. The GO-cDNA further amplified the peak current change. This electrochemical aptasensor showed a low limit of detection of 5 fg/mL as well as good reproducibility with the relative standard deviation (RSD) of 4.38%. Moreover, the detection result of OTA in the rice and oat samples was comparable with that of the enzyme-linked immunosorbent assay (ELISA) kit. In general, the OTA aptasensor used in this work with convenient preparation, low-cost, good selectivity, high sensitivity and acceptable reproducibility can be proposed as a reliable point-of-care (POC) technique for OTA determination.
信号放大对于开发一种可靠的基于一次性丝网印刷碳电极（SPCEs）的生物传感器至关重要，该生物传感器用于在狭窄检测窗口内检测分析物。这项工作展示了一种基于SPCEs的新型无标记电化学适体传感器，用于超灵敏检测赭曲霉毒素A（OTA）。首次研究了易于制备的氧化石墨烯-DNA（GO-DNA）复合物作为信号放大器。基于SPCEs/GO/cDNA-适体/3D-rGO-AuNPs结构的拟议适体传感器是通过适体连接的3D-rGO/AuNPs与其互补DNA连接的GO（GO-cDNA）杂交形成的。OTA的存在通过其特异性适体形成卷曲的OTA-适体复合物并从SPCEs表面释放GO-cDNA来识别。产生的OTA-适体复合物阻碍了传感表面的界面电子转移，导致峰值电流降低。GO-cDNA进一步放大了峰值电流变化。这种电化学适体传感器显示出低检测限为5 fg/mL，以及良好的重现性，相对标准偏差（RSD）为4.38%。此外，大米和燕麦样品中OTA的检测结果与酶联免疫吸附测定（ELISA）试剂盒的结果相当。总体而言，这项工作中使用的OTA适体传感器制备方便、成本低、选择性好、灵敏度高且重现性可接受，可作为一种可靠的即时检测（POC）技术用于OTA测定。
