Gene Detection by Light-to-electric Converting Intercalator and Its Application to DNA

在这项研究中，我们开发了一种新颖的利用光电转换的DNA双链检测系统。检测DNA双链形成的原理如下。1)制备了单链DNA修饰的金电极。2)当形成双链DNA时，Ru的络合物会嵌入并集中在电极表面。3)将可见光照射到电极上，观察到Ru配合物激发产生的光电流。我们使用了一种带有DNA插层配体的多吡啶Ru配合物来检测DNA。以Ru(Bpy)3为对照化合物。以Ru(Bpy)_2dppz作为Ru(Bpy)_2dppz嵌入DNA的配合物。此外，我们还合成了NdI-Ru_2作为负载Ru络合物的线状插层剂。将DNA固定的金电极浸泡在含有光电转换剂(Ru(Bpy)_3，Ru(Bpy)_2dppz，NdI-Ru_2)的溶液中。当可见光照射到电极表面时，在叔胺作为电子供体的存在下，产生了连续的光电流。在形成双链DNA后，Ru(Bpy)_2dppz的光电流增加了36%，NDI-Ru_2的光电流量增加了86%。这一结果表明，金属嵌入剂是通过与DNA双链的亲和力集中在金电极表面的。在NdI-Ru_2的情况下，我们认为，由于NdI作为电子受体，电子通过萘二亚胺顺利地从Ru转移到金电极上。综上所述，我们可以通过使用一台Ru嵌入器的光电流的大小来区分双链和单链DNA。

In this research we developed a novel detection system of DNA duplex using a light-to-electric conversion. The principle of the detection of DNA duplex formation is as follows. 1) The gold electrode modified by single stranded DNA was prepared. 2) When double stranded DNA is formed, ruthenium complex will intercalate and will be concentrated on the electrode surface. 3) Then the visible light is irradiated to the electrode, photocurrent caused by excitation of ruthenium complex will be observed.We used a polypyridyl ruthenium complex carrying DNA intercalating ligand for DNA detection. Ru(bpy)_3 was used as a control compound. Ru(bpy)_2dppz was used as a ruthenium complex carrying a DNA intercalating part. Furthermore, we synthesized NDI-Ru_2 as a threading intercalator carrying ruthenium complex. This type of compound has a smaller dissociation rate from DNA duplex, because it has threading intercalating part connected to two bulky groupsA DNA-immobilized gold electrode was dipped into the solution containing the light-to-electric converting intercalator (Ru(bpy)_3, Ru(bpy)_2dppz, NDI-Ru_2). When the visible light was irradiated to the surface of the electrode, continuous photocurrent occurred in the presence of tertiary amine as an electron donor. The amount of photocurrent increased by 36% in the case of Ru(bpy)_2dppz, 86% in the case of NDI-Ru_2 after the formation of double-stranded DNA. This result suggested that the metallointercalator was concentrated on the surface of gold electrode by its affinity to DNA duplex. In the case of NDI-Ru_2, we consider that electron was smoothly transferred from ruthenium to gold electrode through naphthalenediimide because NDI acts as an electron acceptor. In conclusion, we could discriminate between double stranded and single stranded DNA from the magnitude of the photocurrent using a ruthenium intercalator.