MOLECULAR WIRING TYPE DNA SENSOR

以三（1，10-邻菲咯啉）钴（Ⅱ）配合物[Co（phen）_3^<2+>]为杂交指示剂，巯基修饰的25聚体探针DNA固定在金电极上，研究了人乳头瘤病毒特异性DNA序列的电化学检测。根据先前报道的方法制备三（1，10-菲咯啉）氯化钴（II）。将固定有探针DNA的金电极浸入含有靶DNA的缓冲溶液（pH7.0）中，在65 ℃下进行杂交反应1小时。杂交后，将电极浸入Co（phen）_3^<2+>/0.1M磷酸盐缓冲液（pH7.0）中。在Co（phen）3 ^<2+>/0.1M磷酸盐缓冲溶液（pH 7.0）中进行循环伏安法，用与靶DNA杂交的探针DNA修饰金电极在0.1mM Co（phen）3 ^<2+>/0.1M磷酸盐缓冲溶液（pH 7.0）中的循环伏安峰电流较大 关于我们 当Co（phen）_3^<2+>浓度为0.1mM时，响应电流依赖于靶DNA的浓度。在0.2mM、0.3mM和1.0mM浓度下，Co（phen）_3^&lt;2+&gt;的响应电流与靶DNA浓度的关系不明显，在10 μ M ~ 10 μ M范围内，响应电流与靶DNA浓度呈线性关系<-7><-4>，斜率为10.5nA/ decade。以25聚脱氧核糖核酸（poly-deoxy A）为非互补DNA，用DNA修饰的金电极作探针，在相同的范围内，响应电流几乎没有增加。另一方面，所有电流都比使用探针DNA修饰电极的电流略有降低。DNA修饰电极表面发生了化学变化，这似乎是因为电极在一次测量后重复使用，增加了靶DNA（或聚脱氧A）的浓度。从这些结果表明，与探针DNA互补的DNA的特定序列可以使用钴菲咯啉络合物和探针DNA修饰的金电极检测。少

Electrochemical detection of specific DNA sequence of human papiroma virus was investigated using the gold electrode immobilized with probe DNA through a thiol group and tris(1,10-phenanthroline) cobalt (II) complex [Co(phen)_3^<2+>] as a hybridization indicator.25-mer probe DNA modified with a thiol group at 5' end was immobilized on a gold electrode. Tris(1,10-phenanthroline) cobalt (II) chloride was prepared according to previously reported procedure. The gold electrode immobilized with probe DNA was immersed into buffer solution (pH 7.0) containing target DNA.Hybridization reaction was performed for an hour at 65 C。.After the hybridization, the electrode was immersed into Co(phen)_3^<2+>/0.1M phosphate buffer (pH 7.0). Cyclic voltammetry was performed in Co(phen)_3^<2+>/0.1 M phosphate buffer (pH 7.0).Anodic peak current of cyclic voltammograms of 0.1 mM Co(phen)_3^<2+>/0.1 M phosphate buffer (pH 7.0) using the probe DNA-modified gold electrode hybridized with target DNA was larger … More than that using the probe DNA-modified gold electrode.When the concentration of Co(phen)_3^<2+> was 0.1 mM, the response currents depended on target DNA concentration. However, at another Co(phen)_3^<2+> concentrations of 0.2 mM, 0.3mM and 1.0 mM examined, the response currents did not clearly depend on target DNA concentration.The response currents were linearly related to target DNA concentration in the range from 10^<-7> M to 10^<-4> M with a slope of 10.5 nA / decade. Similar measurement was performed using the probe DNA-modified gold electrode reacted with 25-mer poly-deoxy A as non-complementary DNA.The response currents were hardly increased in the same range. On the other hand, all currents were slightly decreased from that using probe DNA-modified electrode. It seems that the surface of DNA-modified electrode suffer from chemical alteration because the electrode was repeatedly used increasing the concentration of target DNA (or poly-deoxy A) after one measurement. From these results, it was shown that a certain sequence of DNA, which is complementary to probe DNA, can be detected using cobalt phenanthroline complex and probe DNA-modified gold electrode. Less