Pb2+ induced DNA conformational switch from hairpin to G-quadruplex: electrochemical detection of Pb2+
Pb2+ induced DNA conformational switch from hairpin to G-quadruplex: electrochemical detection of Pb2+
复制标题
Pb2 诱导 DNA 构象从发夹转变为 G-四链体：Pb2 的电化学检测
DOI：
10.1039/c1an15080d
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发表时间：
2011-01-01
期刊：
影响因子：
4.2
通讯作者：
Fang, Weihai
中科院分区：
文献类型：
--
作者：
Lin, Zhenzhen;Chen, Yue;Fang, Weihai
以[Fe(CN)(6)]（3-/4-）为氧化还原探针，利用电化学阻抗谱（EIS）研究了Pb2+诱导发夹DNA向g -四联体的构象转换。在Pb2+的存在下，富g的发夹DNA打开茎环，形成g四重结构，导致EIS反映的膜的电荷转移电阻（R-CT）急剧增加。这种结构变化也被圆二色性（CD）测量和紫外-可见光谱分析证实，并通过密度泛函理论（DFT）计算得到。在此基础上，我们开发了一种用于Pb2+检测的无标记电化学DNA生物传感器。随着Pb2+浓度的增加，Pb2+孵育前后的电荷转移电阻RCT差异与50mm ~ 0.5 nM范围内Pb2+浓度的对数呈线性关系。该生物传感器对Pb2+的选择性也优于其他金属离子。这是一种利用g -四联体检测Pb2+的简单且无标记的电化学方法。
Conformational switch from hairpin DNA to G-quadruplex induced by Pb2+ is studied by electrochemical impedance spectroscopy ( EIS) in the presence of [Fe(CN)(6)](3-/4-) as the redox probe. In the presence of Pb2+, the G-rich hairpin DNA opens the stem-loop and forms G-quadruplex structure, which gives rise to a sharp increase in the charge-transfer resistance (R-CT) of the film reflected by the EIS. This structural change is also confirmed by circular dichroism (CD) measurements and UV-Vis spectroscopic analysis and calculated by density functional theory (DFT). On the basis of this, we develop a label-free electrochemical DNA biosensor for Pb2+ detection. With increasing concentrations of Pb2+, the differences in the charge-transfer resistance RCT before and after the Pb2+ incubation is linearly dependent on the logarithm of Pb2+ concentration within a range from 50 mM to 0.5 nM. The biosensor also exhibits good selectivity for Pb2+ over other metal ions. This is a simple and label-free electrochemical method for Pb2+ detection making use of the G-quadruplex.