Department of Chemistry, Faculty of Science, Yazd University, Yazd, 89195-741, Iran.
Anal Methods. 2021 May 6;13(17):2021-2029. doi: 10.1039/d1ay00330e.
In the present study, a label-free electrochemical genosensor was designed based on ZnS quantum dots functionalized with l-cysteine (Cys-ZnS-QDs) to detect miR-200a, as a special ovarian cancer biomarker. The Cys-ZnS-QD genosensor was characterized by transmission electron microscopy (TEM), UV-Vis absorption and fluorescence methods. Cys-ZnS-QDs are electrodeposited on the glassy carbon electrode surface and act as a suitable substrate for immobilization of the DNA probe. The effective parameters in the preparation of the genosensor are optimized to improve its analytical performance. The analytical performance of the genosensor has been investigated using electrochemical impedance spectroscopy. Under optimal conditions, the linear range and the detection limit of miR-200a were found to be 1.0 × 10-14 to 1.0 × 10-6 M and 8.4 fM. In addition, the genosensor is used to detect the target complementary miRNA strand from a single-base mismatch miRNA strand. Finally, this label-free electrochemical biosensor was used to detect miR-200a in human plasma without using any amplification method.
在本研究中，设计了一种基于巯基-L-半胱氨酸（Cys-ZnS-QDs）功能化的 ZnS 量子点的无标记电化学基因传感器，用于检测 miR-200a，作为一种特殊的卵巢癌生物标志物。Cys-ZnS-QD 基因传感器通过透射电子显微镜（TEM）、紫外-可见吸收和荧光方法进行表征。Cys-ZnS-QDs 被电沉积在玻碳电极表面上，并作为固定 DNA 探针的合适基底。优化了基因传感器制备过程中的有效参数，以提高其分析性能。使用电化学阻抗谱研究了基因传感器的分析性能。在最佳条件下，miR-200a 的线性范围和检测限分别为 1.0×10-14 至 1.0×10-6 M 和 8.4 fM。此外，该基因传感器可用于检测单碱基错配 miRNA 链的靶互补 miRNA 链。最后，该无标记电化学生物传感器用于检测人血浆中的 miR-200a，而无需使用任何扩增方法。
