MOLECULAR WIRING TYPE DNA SENSOR

用探针DNA固定的金电极，通过巯基和三（1,10-菲罗啉）钴（II）配合物[Co(phen)_3^<2+>]作为杂交指示剂，研究了对人乳头瘤病毒特异性DNA序列的电化学检测。用5'端巯基修饰的25-mer探针DNA固定在金电极上。三（1,10-邻菲罗啉）氯化钴（II）根据先前报道的程序制备。将固定探针DNA的金电极浸入含有目标DNA的缓冲液（pH 7.0）中。在65℃下杂交反应1小时。杂交后，电极浸入Co(phen)_3^<2+>/0.1M磷酸盐缓冲液（pH 7.0）中。循环伏安法在Co(phen)_3^<2+>/0.1 M磷酸盐缓冲液（pH 7.0）中进行。在0.1 mM Co(phen)_3^<2+>/0.1 M磷酸盐缓冲液（pH 7.0）的循环伏安图中，探针DNA修饰金电极与靶DNA杂交得到的阳极峰值电流大于探针DNA修饰金电极。当Co(phen)_3^<2+>浓度为0.1 mM时，响应电流与靶DNA浓度有关。然而，在Co(phen)_3^<2+>浓度为0.2 mM， 0.3mM和1.0 mM时，响应电流不明显依赖于靶DNA浓度。在10^<-7> M至10^<-4> M范围内，响应电流与靶DNA浓度呈线性相关，斜率为10.5 nA / 10年。使用探针DNA修饰的金电极与25聚脱氧A作为非互补DNA反应，进行类似的测量。在相同的范围内，响应电流几乎没有增加。另一方面，与探针dna修饰电极相比，所有电流都略有下降。DNA修饰电极的表面似乎发生了化学变化，因为电极在一次测量后反复使用，增加了目标DNA（或聚脱氧A）的浓度。这些结果表明，利用钴-菲罗啉配合物和探针DNA修饰的金电极可以检测到与探针DNA互补的特定DNA序列。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