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外文期刊>International Journal of Electrochemical Science
>A Reusable Electrochemical Aptasensor for the Sensitive Detection of Pb(II) with an Electrodeposited AuNP-Modified Electrode based on the Formation of a Target-Induced G- Quadruplex
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A Reusable Electrochemical Aptasensor for the Sensitive Detection of Pb(II) with an Electrodeposited AuNP-Modified Electrode based on the Formation of a Target-Induced G- Quadruplex
A label-free and reusable electrochemical aptasensor for Pb(II) detection using the G-quadruplex-Pb(II) binding interaction and target-induced strand release is proposed. This strategy is based on the changes in the electrochemical impedance spectroscopy (EIS) results caused by the separable structure of aptamer DNA rich in guanine. Additionally, a controllable gold nanoparticle (AuNP) layer was electrochemically reduced on a glassy carbon electrode (GCE) surface as the modified substrate for aptamer DNA. The AuNPs provided a large surface area and more active sites during immobilization and hybridization, which enhanced the EIS signal. In the presence of Pb(II), the EIS intensity of the aptasensor decreased significantly due to the special interaction between Pb(II) and G4-DNA, which prompted the aptamer to construct a G-quadruplex and caused the two DNA strands to untwist. This untwisting resulted in the release of G4-DNA. The aptamer probe structure of the double strand was then altered to a single strand because of the formation of the Pb(II)-G-quadruplex compound by the binding of Pb(II) on the aptamer. This binding changed the electron transfer kinetics between the surface of the electrode and the aptamer DNA strand, leading to a decrease in the EIS response. Results show that the charge transfer resistance decreased linearly and proportionally to the log function of the Pb(II) concentration from 0.001 to 100 渭g/L. Moreover, the developed aptasensor demonstrated a high selectivity toward Pb(II), and the calculated detection limit was 0.0046 nM (S/N = 3), which indicated that our proposed electrochemical aptasensor was capable of Pb(II) detection at a trace level.
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机译：提出了使用G-Quadreple-Pb（II）结合相互作用和靶诱导的链释放的Pb（II）检测的无标记和可重复使用的电化学Aptasensor。该策略基于电化学阻抗光谱（EIS）的变化，其由富含鸟嘌呤的适体DNA可分离结构引起的结果。另外，在玻璃状碳电极（GCE）表面上电化学减少可控金纳米颗粒（AUNP）层作为适于适体DNA的改性基材。 AUNPS在固定和杂交期间提供了大的表面积和更具活性位点，其增强了EIS信号。在PB（ii）的存在下，由于PB（II）和G4-DNA之间的特殊相互作用，APTasensor的EIS强度显着降低，这促使适体构建G-Quadreplex并使两个DNA链向Untwist引起。这种不呈现导致释放G4-DNA。然后，双链的适体探针结构被改变为单链，因为Pb（II）-g-四氨水化合物通过置换剂上的PB（II）的结合形成Pb（II）-d-己烷化合物。该结合改变了电极表面和适体DNA链之间的电子转移动力学，导致EIS反应的降低。结果表明，电荷转移电阻线性和比例地降低，与PB（II）浓度从0.001-100×g / L的Log函数成比例地降低。此外，开发的aptasensor对Pb（II）的选择性高，计算的检测限为0.0046nm（S / N = 3），表明我们所提出的电化学Aptasensor能够在痕量水平下检测PB（II）检测。
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