School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry, Nanjing University, China.
Analyst. 2011 May 21;136(10):2090-9. doi: 10.1039/c0an01032d. Epub 2011 Apr 12.
In this article we studied the permeable characteristics of thiol-modified double-stranded DNA (ds-DNA) self-assembled monolayers (SAMs) on a gold substrate assembled under different NaCl concentrations by electrochemical methods. It was based on the inspection of five important parameters including interfacial capacitance (C), phase angle (Φ(1 Hz)), ions transfer resistance (R(it)), current density difference (Δj) and electron transfer rate (k(et)) through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Three sections were included: (1) Investigation of the relationships of C, Φ(1 Hz), R(it), Δj and k(et) with NaCl concentrations and comparison with the reports from literature. Experimental results showed that ds-DNA-SAMs were permeable films. (2) Construction of a simple model for exploring the permeable characteristics of ds-DNA-SAMs on gold. (3) Confirmation of the simple model by chronocoulometry (CC) and application of the model to explain the permeable mechanism. This study was significant for exploring the mechanism of electron transfer through the interior of ds-DNA duplex helix.
本文采用电化学方法研究了不同 NaCl 浓度下组装在金基底上的巯基修饰双链 DNA(ds-DNA)自组装单层(SAMs)的渗透特性。通过循环伏安法(CV)和电化学阻抗谱(EIS)检测了界面电容(C)、相位角(Φ(1 Hz))、离子转移电阻(R(it))、电流密度差(Δj)和电子转移速率(k(et))等五个重要参数。全文分为三个部分：(1)研究了 C、Φ(1 Hz)、R(it)、Δj 和 k(et)与 NaCl 浓度的关系，并与文献报道进行了比较。实验结果表明 ds-DNA-SAMs 是具有渗透性的薄膜。(2)构建了一个简单的模型来探索 ds-DNA-SAMs 在金上的渗透特性。(3)通过计时库仑法(CC)验证了该模型，并应用该模型解释了渗透机制。该研究对于探索电子通过 ds-DNA 双螺旋内部的转移机制具有重要意义。
