Yang Linlin, Li Xiaoyu, Li Xi, Yan Songling, Ren Yinna, Wang Mengmeng, Liu Peng, Dong Yulin, Zhang Chaocan
Department of Chemistry, School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
Department of Chemistry, School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
Anal Biochem. 2016 Jan 1;492:56-62. doi: 10.1016/j.ab.2015.09.011. Epub 2015 Sep 25.
We demonstrate a novel protocol for sensitive in situ label-free electrochemical detection of DNA hybridization based on copper complex (Cu(phen)2, where phen = 1,10-phenanthroline) and graphene (GR) modified glassy carbon electrode. Here, Cu(phen)2 acted advantageously as both the electrochemical indicator and the anchor for probe DNA immobilization via intercalative interactions between the partial double helix structure of probe DNA and the vertical aromatic groups of phen. GR provided large density of docking site for probe DNA immobilization and increased the electrical conductivity ability of the electrode. The modification procedure was monitored by electrochemical impedance spectroscopy (EIS). Square-wave voltammetry (SWV) was used to explore the hybridization events. Under the optimal conditions, the designed electrochemical DNA biosensor could effectively distinguish different mismatch degrees of complementary DNA from one-base mismatch to noncomplementary, indicating that the biosensor had high selectivity. It also exhibited a reasonable linear relationship. The oxidation peak currents of Cu(phen)2 were linear with the logarithm of the concentrations of complementary target DNA ranging from 1 × 10(-12) to 1 × 10(-6) M with a detection limit of 1.99 × 10(-13) M (signal/noise = 3). Moreover, the stability of the electrochemical DNA biosensor was also studied.
我们展示了一种基于铜配合物（[Cu(phen)₂]²⁺，其中phen = 1,10 - 菲咯啉）和石墨烯（GR）修饰玻碳电极的用于DNA杂交灵敏原位无标记电化学检测的新方案。在此，[Cu(phen)₂]²⁺既有利地充当电化学指示剂，又通过探针DNA的部分双螺旋结构与phen的垂直芳香基团之间的嵌入相互作用作为固定探针DNA的锚定物。GR为探针DNA固定提供了高密度的对接位点，并提高了电极的导电能力。修饰过程通过电化学阻抗谱（EIS）进行监测。方波伏安法（SWV）用于探究杂交事件。在最佳条件下，所设计的电化学DNA生物传感器能够有效区分互补DNA从单碱基错配到非互补的不同错配程度，表明该生物传感器具有高选择性。它还呈现出合理的线性关系。[Cu(phen)₂]²⁺的氧化峰电流与互补靶标DNA浓度的对数在1×10⁻¹²至1×10⁻⁶ M范围内呈线性关系，检测限为1.99×10⁻¹³ M（信号/噪声 = 3）。此外，还研究了电化学DNA生物传感器的稳定性。
