MOLECULAR WIRING TYPE DNA SENSOR

以三(1，10-二氮杂菲)钴(II)配合物[Co(Phen)_3‘&lt；2&gt；]为杂交指示剂，将5’端硫醇修饰的25聚体探针DNA固定在金电极上，对人乳头瘤病毒特异性DNA序列进行了电化学检测。三(1，10-二氮杂菲)氯化钴(II)的制备方法与文献报道一致。用探针DNA固定的金电极浸泡在含有目的DNA的缓冲液(pH 7.0)中，在65℃下杂交反应1h。杂交后，将电极浸入Co(Phen)_3和lt；2&gt；/0.1M磷酸盐缓冲液(pH 7.0)中。在0.1M磷酸盐缓冲液(pH 7.0)中，用探针修饰的金电极与靶DNA杂化后，0.1 mM的Co(Phen)3‘&lt；2&gt；/0.1M磷酸盐缓冲液(pH 7.0)的循环伏安峰电流较大的…当Co(Phen)3^和lt；2&gt；浓度为0.1 mM时，响应电流依赖于靶DNA浓度。然而，在0.2 mM、0.3 mM和1.0 mM的Co(Phen)_3、0.3和1.0 mM浓度下，响应电流与靶DNA浓度没有明显的相关性，响应电流与靶DNA浓度在10^~(-7)~10^~(-4)M范围内呈良好的线性关系，斜率为10.5nA/cm2。用探针DNA修饰的金电极与25聚体多聚脱氧核糖核酸作为非互补DNA进行了类似的测量，在相同的范围内响应电流几乎没有增加。另一方面，与使用探针DNA修饰电极相比，所有电流都略有降低。DNA修饰电极的表面似乎发生了化学变化，这是因为电极在一次测量后重复使用，增加了目标DNA(或多聚脱氧A)的浓度。这些结果表明，用钴邻菲咯啉络合物和探针DNA修饰的金电极可以检测到与探针DNA互补的一定序列的DNA。较少

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