Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, Jiangsu Province Hi-Tech Key Laboratory for Bio-medical Research, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China.
College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China.
Biosens Bioelectron. 2017 May 15;91:347-353. doi: 10.1016/j.bios.2016.12.054. Epub 2016 Dec 24.
Telomerase has become one of the most typical tumor marker because it is closely related to cancers. In this paper, a simple label-free electrochemical detection of telomerase activity by using methylene blue (MB) as a G-quadruplex binding probe was proposed, avoiding commonly used complex label procedures, nano-probe synthesis, complicated electrode modification, probe immobilization or signal amplification. In the presence of telomerase substrate (TS) primer, the binding of MB on primer was weak. When repeats of (TTAGGG) were extended on the TS primer under the action of telomerase, they formed multiple G-quadruplexes with the help of K. As a result, a large amount of MB bounded to multiple G-quadruplexes because they have more strong interaction with G-quadruplexes than TS primer. As a result, the diffusion current of MB decreased sharply, which was strongly dependent on the telomerase activity. The DPV current change has a linear correlation with the logarithm of HeLa cell number in the range of 10-10,000 cells, with the detection limit of 3 cells. The high sensitivity was due to the formed multiple G-quadruplexes. Using indium tin oxide (ITO) as working electrode without modification ensured the good reproducibility of the method. The method was also simple, rapid, and has been successfully applied in the telomerase activity detection in urine with good selectivity and reproducibility, which is significant for cancer diagnosis, anticancer drugs screening, and cancer therapy evaluation.
端粒酶已成为最典型的肿瘤标志物之一，因为它与癌症密切相关。在本文中，提出了一种简单的无标记电化学检测端粒酶活性的方法，该方法使用亚甲蓝（MB）作为 G-四链体结合探针，避免了常用的复杂标记程序、纳米探针合成、复杂的电极修饰、探针固定或信号放大。在端粒酶底物（TS）引物存在的情况下，MB 与引物的结合较弱。当在端粒酶的作用下，（TTAGGG）重复序列在 TS 引物上延伸时，在 K 的帮助下，它们形成了多个 G-四链体。结果，大量的 MB 结合到多个 G-四链体上，因为它们与 G-四链体的相互作用比 TS 引物更强。因此，MB 的扩散电流急剧下降，这与端粒酶活性强烈相关。DPV 电流变化与 HeLa 细胞数在 10-10,000 个细胞范围内的对数呈线性相关，检测限为 3 个细胞。高灵敏度归因于形成的多个 G-四链体。使用氧化铟锡（ITO）作为工作电极而无需修饰，确保了该方法具有良好的重现性。该方法还简单、快速，并已成功应用于尿液中端粒酶活性的检测，具有良好的选择性和重现性，这对于癌症诊断、抗癌药物筛选和癌症治疗评估具有重要意义。
