Study of DNA-Ferrocene Conjugate for Application to Gene Targeting

介绍了两个电化学基因传感器的应用实例。我们首先介绍了一种含二茂铁基的二茂铁衍生物。使用质粒DNA（pBR 322）的凝胶迁移试验表明，该化合物在UV辐射后与DNA双链不可逆地结合。这是由于DNA双链体中的peptide部分和核酸酶之间的光加合物形成。在循环伏安法测量中，该化合物给出可逆的氧化还原波，这归因于二茂铁部分的电极反应。因此，该化合物有望用于双螺旋DNA的氧化还原标记;与DNA共价结合的试剂使双链具有氧化还原活性功能。基于这些结果，在DNA修饰电极系统中的组合使用中证明了电化学基因靶向的可能应用;首先用靶DNA处理用DNA探针修饰的金电极以形成DNA双链，在随后的处理中产生氧化还原波。 ...更多信息 而没有杂交过程的DNA修饰电极（单链DNA）的氧化还原活性约为二分之一。接下来，介绍了一种能够报告DNA杂交的DNA修饰电极。我们一直在研究各种DNA修饰电极系统。利用离子通道传感器的原理，其中一些已经应用于DNA结合分子和离子以及DN结合蛋白的电化学传感。在这里，化学感受性表面吸附层被改进为DNA/二茂铁双层格式，以提供分析物依赖的电化学信号。电极制备如下进行：首先用11-氨基烷乙醇修饰金电极，随后与1，1-二茂铁二甲酸反应。与具有氨基功能的寡脱氧核糖核酸反应得到具有DNA/二茂铁界面结构的修饰电极。循环伏安法测量显示，由于二茂铁的电极反应的可逆氧化还原波抑制到一半后形成的DNA层。如果用具有与固定的DNA特定的碱基序列的DNA水溶液处理电极，则氧化还原波进一步被抑制到十分之一。这些结果表明，该电极系统可以适用于电化学检测的DNA杂交没有任何种类的报告分子。少

Two examples of electrochemical gene sensor are described. We first introduced a ferrocene derivative with psoralen moiety. A gel-shift assay using a plasmid DNA (pBR322) showed that the compound binds irreversibly to DNA double strands upon UV radiation. This is due to photoadduct formation between the psoralen moiety and nucleases in the DNA duplex. In cyclic voltammetric measurements, the compound gave reversible redox waves, which were ascribed to the electrode reaction of the ferrocene moiety. Thus, the compound was expected to be useful for redox labeling of double-helical DNA ; the reagent which is bound covalently to DNA gives the double-strand a redox-active function. Based on these results, a possible application to electrochemical gene targeting was demonstrated in a combined use in a DNA-modified electrode system ; a gold electrode modified with a DNA probe was first treated with the target DNA to form the DNA double-strand gave redox waves upon a subsequent treatment with … More the labeling reagent while the redox activity for the DNA-modified electrode without the hybridization procedure (single-stranded DNA) was about one-half. Next, a DNA modified electrode, which can report DNA hybridization, was introduced. We have been investigating various DNA-modified electrode systems. By taking advantage of the principle of an "ion-channel sensor", some of those have been applying to electrochemical sensing of DNA-binding molecules and ions as well as DN-binding proteins. Here, the chemoreceptive surface adlayer was improved to a DNA/ferrocene bilayer format to give an analyte-dependent electrochemical signal. Electrode preparation was made as follows ; a gold electrode was first modified with 11-aminoalkanethiol and was subsequently reacted with 1, 1-ferrocendicarboxylic acid. Reaction with an oligodeoxyribonucleic acid with an amino function gave a modified electrode with a DNA/ferrocene interfacial structure. Cyclic voltammetric measurements revealed those reversible redox waves due to the electrode reaction of ferrocene suppressed to one-half upon formation of the DNA layer. If the electrode was treated with an aqueous solution of DNA having specific base sequence to the immobilized DNA, the redox waves were further suppressed to one-tenth. These results suggest that the electrode system can be applicable to the electrochemical detection of DNA hybridization without any kind of reporter molecules. Less