In this study, a simple and cost-effective electrochemical DNA biosensor was developed for sensitive detection of mycobacterium tuberculosis (TB). Nanocomposite of zinc oxide (ZnO) and gold nanoparticles (AuNPs) was used as a platform for immobilizing thiolated TB DNA (probe DNA). ZnO was electrodeposited on a glassy carbon electrode by potentiostat electrolysis of Zn (NO3)2 solution at -1.0 V (vs. Ag/AgCl), then AuNPs were loaded as the second layer at -0.4 V from HAuCl4 solution. Thiolated probe DNA was then covalently attached to AuNPs. Anodic peak current of Fe (CN)63-/4- was followed in hybridization experiments and a linear calibration curve was obtained in concentration range of 2.5-250 pM and limit of detection (LOD) of 1.8 pM for target DNA. The label-free TB biosensor exhibited high selectivity, suitable stability, and reproducibility.

中文翻译：

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氧化锌-金纳米复合材料可作为无标记DNA生物传感器的合适平台。

在这项研究中，开发了一种简单且经济高效的电化学DNA生物传感器，用于结核分枝杆菌（TB）的灵敏检测。氧化锌（ZnO）和金纳米颗粒（AuNPs）的纳米复合材料用作固定硫醇化TB DNA（探针DNA）的平台。通过在-1.0 V（vs. Ag / AgCl）下对Zn（NO3）2溶液进行恒电位电解，将ZnO电沉积在玻璃碳电极上，然后从HAuCl4溶液中以-0.4 V加载AuNP作为第二层。然后将硫酰化的探针DNA共价附于AuNP。在杂交实验中跟踪Fe（CN）63- / 4-的阳极峰值电流，并在2.5-250 pM的浓度范围内和目标DNA的检测限（LOD）为1.8 pM时获得线性校准曲线。无标记的TB生物传感器显示出高选择性，合适的稳定性和可重复性。