Department of General Surgery, The Second Xiang-ya Hospital, Central South University, Changsha, 410011, China.
Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China.
Mikrochim Acta. 2019 Jan 10;186(2):96. doi: 10.1007/s00604-018-3223-6.
An ultrasensitive electrochemical sensor is described for the determination of the activity of telomerase. It is based on a DNA-generated current that is due to the reaction of the phosphate groups on DNA with molybdate to form a redox-active molybdophosphate. A telomerase substrate primer was first immobilized on a gold electrode. In the presence of telomerase and deoxyribonucleoside triphosphates (dNTPs), the primer can be extended with repetitive nucleotide sequences (TTAGGG). The subsequent reaction of the sensor with molybdate results in the enhancement of electrochemical current intensity due to an increased amount of nucleotides on the electrode. Sensitivity can be further improved by introducing a hairpin probe that partially hybridizes with the repetitive TTAGGG sequence and further enhances the amount of DNA on the electrode. The biosensor, best operated at 0.2 V (vs. Ag/AgCl) shows a linear response to telomerase activity from 1×10 to 10 Hela cells mL. The assay was applied to the detection of telomerase activity in HeLa cancer cells treated with the anticancer drug epigallocatechin gallate, and the results indicate that it holds great potential in anticancer drug screening. Graphical abstract Schematic presentation of an ultrasensitive electrochemical sensor for the determination of telomerase activity based on DNA generated electrochemical current. dNTPs in the scheme represents deoxyribonucleoside triphosphates.
一种超灵敏的电化学传感器，用于测定端粒酶的活性。它基于与钼酸盐反应形成氧化还原活性的钼磷酸酯的 DNA 产生电流。首先将端粒酶底物引物固定在金电极上。在端粒酶和脱氧核糖核苷三磷酸（dNTPs）存在的情况下，引物可以通过重复的核苷酸序列（TTAGGG）进行延伸。随后，传感器与钼酸盐反应，由于电极上核苷酸的数量增加，导致电化学电流强度增强。通过引入部分与重复 TTAGGG 序列杂交的发夹探针，可以进一步提高电极上的 DNA 数量，从而进一步提高灵敏度。该生物传感器在 0.2 V（相对于 Ag/AgCl）下最佳运行，对 1×10 至 10 个 Hela 细胞 mL 的端粒酶活性表现出线性响应。该测定法用于检测用抗癌药物表没食子儿茶素没食子酸酯处理的 HeLa 癌细胞中端粒酶活性，结果表明它在抗癌药物筛选中具有很大的潜力。 示意图 基于 DNA 产生的电化学电流测定端粒酶活性的超灵敏电化学传感器的示意图。方案中的 dNTPs 代表脱氧核糖核苷三磷酸。
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