Immobilization, hybridization, and oxidation of synthetic DNA on gold surface: electron transfer investigated by electrochemistry and scanning tunneling microscopy.
Immobilization, hybridization, and oxidation of synthetic DNA on gold surface: electron transfer investigated by electrochemistry and scanning tunneling microscopy.
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金表面合成 DNA 的固定、杂交和氧化：通过电化学和扫描隧道显微镜研究电子转移。
DOI：
10.1016/j.aca.2009.03.050
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发表时间：
2009
影响因子：
6.2
通讯作者：
Zhou,Anhong
中科院分区：
文献类型：
--
作者：
McEwen,GeraldD;Chen,Fan;Zhou,Anhong
对电解质/DNA/固体表面之间界面电子转移的基本认识将有助于DNA分子电检测的设计。本研究以电化学方法研究了人工合成DNA（致病性微小隐孢子虫DNA序列）在金表面自组装的电子转移特性。通过循环伏安法（CV）和电化学阻抗谱（EIS）研究了固定顺序对界面ET相关参数如扩散系数（D 0）、表面覆盖度（θR）和单分子层厚度（di）的影响。DNA表面密度（ΓDNA）通过在初始循环伏安法扫描期间电氧化电流峰的电荷的积分来确定。结果表明，不同修饰条件下DNA表面密度的大小顺序为：ΓDNA（dsS-DNA/Au）>ΓDNA（MCH/dsS-DNA/Au）>ΓDNA（dsS-DNA/MCH/Au）。DNA修饰金表面的电氧化反应主要是以5.51电子转移机制氧化鸟嘌呤和腺嘌呤，以3电子转移机制氧化脱附DNA和MCH。扫描隧道显微镜形貌和电流图像分析表明，各表面修饰后的表面电导率大小顺序为：dsS-DNA/Au<MCH/dsS-DNA/Au<氧化MCH/dsS-DNA/Au<Hoechst/氧化MCH/dsS-DNA/Au。从这项研究的结果表明，在固定顺序的变化的组合可能会提供一个替代的方法优化的DNA杂交和进一步发展的电检测的DNA。
Fundamental understanding of interfacial electron transfer (ET) among electrolyte/DNA/solid-surface will facilitate the design for electrical detection of DNA molecules. In this report, the electron transfer characteristics of synthetic DNA (sequence from pathogenic Cryptosporidium parvum) self-assembled on a gold surface was electrochemically studied. The effects of immobilization order on the interface ET related parameters such as diffusion coefficient (D0), surface coverage (θR), and monolayer thickness (di) were determined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). DNA surface density (ΓDNA) was determined by the integration of the charge of the electro-oxidation current peaks during the initial cyclic voltammetry scans. It was found that the DNA surface densities at different modifications followed the order: ΓDNA(dsS-DNA/Au)>ΓDNA(MCH/dsS-DNA/Au)>ΓDNA(dsS-DNA/MCH/Au). It was also revealed that the electro-oxidation of the DNA modified gold surface would involve the oxidation of nucleotides (guanine and adenine) with a 5.51 electron transfer mechanism and the oxidative desorption of DNA and MCH molecules by a 3 electron transfer mechanism. STM topography and current image analysis indicated that the surface conductivity after each surface modification followed the order: dsS-DNA/Au<MCH/dsS-DNA/Au<oxidized MCH/dsS-DNA/Au<Hoechst/oxidized MCH/dsS-DNA/Au. The results from this study suggested a combination of variations in immobilization order may provide an alternative approach for the optimization of DNA hybridization and the further development for electrical detection of DNA.