Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079, PR China.
Biosens Bioelectron. 2010 Jun 15;25(10):2313-7. doi: 10.1016/j.bios.2010.03.019. Epub 2010 Mar 20.
In this paper the direct electrochemistry of double-stranded DNA (dsDNA) was investigated on ordered mesoporous carbon (OMC) modified carbon ionic liquid electrode (CILE). CILE was prepared by mixing graphite powder with 1-ethyl-3-methylimidazolium ethylsulphate ([EMIM]EtOSO(3)) and liquid paraffin. A stable OMC film was formed on the surface of CILE with the help of Nafion to get a modified electrode denoted as Nafion-OMC/CILE. Due to the specific characteristics of OMC and IL present on the electrode surface, the fabricated electrode showed good electrochemical performances to different electroactive molecules. The electrochemical responses of dsDNA were carefully investigated on this electrode with two irreversible oxidation peak appeared at +1.250 V and +0.921 V (vs. SCE), which was corresponding to the oxidation of adenine and guanine residues in dsDNA structure. The electrochemical behaviors of dsDNA were carefully investigated on the Nafion-OMC/CILE. Experimental results indicated that the electron transfer rate was promoted with the increase of the oxidation peak current and the decrease of the oxidation peak potential, which was due to the electrocatalytic ability of OMC on the electrode surface. Under the optimal conditions the oxidation peak current increased with dsDNA concentration in the range of 10.0-600.0 microg mL(-1) by differential pulse voltammetry (DPV) with the detection limit of 1.2 microg mL(-1) (3sigma).
本文研究了有序介孔碳（OMC）修饰碳离子液体电极（CILE）上双链 DNA（dsDNA）的直接电化学。CILE 通过将石墨粉与 1-乙基-3-甲基咪唑硫酸乙酯盐 ([EMIM]EtOSO(3)) 和液体石蜡混合制备而成。在 Nafion 的帮助下，在 CILE 表面形成了稳定的 OMC 薄膜，得到了一种修饰电极，记为 Nafion-OMC/CILE。由于电极表面存在 OMC 和 IL 的特殊特性，制备的电极对不同电活性分子表现出良好的电化学性能。在该电极上仔细研究了 dsDNA 的电化学响应，出现了两个不可逆氧化峰，分别在 +1.250 V 和 +0.921 V（相对于 SCE），这对应于 dsDNA 结构中腺嘌呤和鸟嘌呤残基的氧化。在 Nafion-OMC/CILE 上仔细研究了 dsDNA 的电化学行为。实验结果表明，随着氧化峰电流的增加和氧化峰电位的降低，电子转移速率得到了促进，这是由于 OMC 在电极表面的电催化能力。在最佳条件下，通过差分脉冲伏安法（DPV）在 10.0-600.0 µg mL(-1) 范围内，氧化峰电流随 dsDNA 浓度的增加而增加，检测限为 1.2 µg mL(-1)（3sigma）。
