College of Chemistry and Materials Science, Fujian Normal University, Fuzhou, Fujian 350002, China.
Analyst. 2010 Nov;135(11):2913-7. doi: 10.1039/c0an00485e. Epub 2010 Sep 28.
Remarkable direct electrochemical behaviors of thermally denatured calf thymus DNA (ssDNA) on the poly(methyl methacrylate)-graphite powder microcomposite electrode (PMMA/GME) were observed and investigated. The result indicated that the PMMA/GME showed great promotion of the electrochemical response towards the ssDNA oxidation due to the specific characteristics of the nanostructured interface on the resultant composite electrode. Two irreversible oxidation peaks at +1.04 and +0.76 V with obvious negative movement of oxidation potential and increase of the oxidation current (vs. Ag/AgCl) were observed on the PMMA/GME, which corresponded to the oxidation of adenine and guanine residues in the ssDNA molecules. Therefore, detection of ssDNA was then performed at the PMMA/GME. Under the optimal conditions, a good linear relationship was obtained between the oxidation peak currents of guanine or adenine residues and the ssDNA concentration in the range of 5.9 × 10(-3) to ca. 1.1 mg mL(-1) with a detection limit of 1.0 μg mL(-1). This PMMA/GME exhibits some outstanding advantages, such as ease of fabrication, high stability, renewable surface, excellent stability, mechanical rigidity and high electrochemical reactivity, which holds huge promise for further DNA biosensor design.
在聚甲基丙烯酸甲酯-石墨粉微复合电极（PMMA/GME）上观察到并研究了热变性小牛胸腺 DNA（ssDNA）的显著直接电化学行为。结果表明，由于所得复合电极上纳米结构界面的特殊特性，PMMA/GME 对 ssDNA 氧化的电化学响应具有很大的促进作用。在 PMMA/GME 上观察到两个不可逆的氧化峰，在+1.04 和+0.76 V 处，氧化电位明显负移，氧化电流（相对于 Ag/AgCl）增加，这对应于 ssDNA 分子中腺嘌呤和鸟嘌呤残基的氧化。因此，然后在 PMMA/GME 上进行 ssDNA 的检测。在最佳条件下，鸟嘌呤或腺嘌呤残基的氧化峰电流与 ssDNA 浓度在 5.9×10(-3)至约 1.1 mg mL(-1)的范围内呈良好的线性关系，检测限为 1.0 μg mL(-1)。这种 PMMA/GME 具有一些突出的优点，例如易于制造、高稳定性、可再生表面、优异的稳定性、机械刚性和高电化学活性，这为进一步的 DNA 生物传感器设计提供了巨大的潜力。
