Electrochemistry of Reclox-Modified DNA Monolayer

金属表面氧化还原反应性DNA组装单层对于电化学DNA传感器和基于DNA的电子器件的发展具有重要意义。我们先前制备了含有2-O-（2-蒽醌基甲基）尿嘧啶的DNA片段，发现它们可以选择性地和它们互补的DNA序列强结合。重要的是，蒽醌（AQ）片段可以放置在双螺旋DNA的预定碱基对口袋中。我们期望该aq修饰的DNA可以作为测定DNA序列的电化学探针。本研究的主要目的是研究在金电极表面组装的aq修饰DNA的电化学性质。首先，我们制备了通过巯基修饰连接到金电极上的aq修饰DNA双链。一个组装的DNA单层（系统1）在氧化还原中心和电极表面之间有一个碱基不匹配。另一个（系统II）由相同的不匹配组成，但在氧化还原中心之外。电化学测量显示。系统I完全匹配DNA的电子转移（ET）速率估计为~50s^<-1>。系统1的错配DNA确实显示出更慢的ET速率。正如预期的那样，在系统II中，完全匹配和不匹配DNA的ET率相似（-50 ^<-1>）。然后，通过传统的测量方法，从减少的电化学反应中确定DNA中不匹配的存在。该技术可应用于SNP分型的杂交分析。重要的特点是，该分析不需要任何额外的试剂，催化剂，目标标记，和洗涤步骤。因此，本方法是一种简便易行的DNA单碱基错配检测方法。我们进一步研究了基于金属表面DNA链交换的SNP分型的其他可能性。氧化还原修饰的双链DNA在金属表面组装成单层。我们已经获得了几个实验结果，表明这种类型的氧化还原- dna结合电极可以通过简单的电化学分析用于SNP检测。DNA链交换技术已应用于核酸适配体生物传感器的研制。链交换方法的结果将在下一个资助期详细报告。少

Redox-resposive DNA assembled monolayer at a metal surface is important in relation to developments of electrochemical DNA sensors and DNA-based electronic devices.We previously prepared 2-O-(2-anthraquinoylmethyl)uridine-containing DNA fragments and found that they can bind selectively and strongly to their complementary DNA sequences. Importantly, the anthraquinone (AQ) moiety can be placed at the predetermined base-pair pocket in double helical DNA. We anticipated that the AQ-modified DNA could be used as an electrochemical probe for DNA sequence determination. The main purpose of the present research is to investigate electrochemical properties of the AQ-modified DNA assembled on a gold electrode surface.First, we prepared AQ-modified DNA duplex attached via thiol-modification onto a gold electrode. One assembled DNA monolayer (system 1) has a single base mismatch between the redox-center and the electrode surface. And the other (system II) consists of the same mismatch but at the … More outside of the redox-center. Electrochemical measurements revealed. that the electron transfer (ET) rate for the fully matched DNA of system I was estimated to be ~50s^<-1>. The mismatch-containing DNA of system I indeed showed much slower ET rate. As expected, in system II, the ET rates for fully matched and mismatched DNA were similar (-50s^<-1>).Then, the presence of mismatch in DNA was determined from the reduced electrochemical responses by a conventional measurement. The technique can be applied to hybridization assays of SNP typing. The important features are that the assay does not require any extra reagents, catalyst, target labeling, and washing steps. Therefore, the present method is a promising way for simple and convenient detection of single base mismatches in DNA.We further investigated other possibility for SNP typing that is based on DNA strand exchange at a metal surface. Redox-modified double strand DNA was assembled as monolayer at a metal surface. We have obtained several experimental results that this type of redox-DNA bound electrodes may be used for SNP detection by a simple electrochemical assays. DNA strand exchange has been applied to developments of aptamer-based biosensors. The results on strand exchange approach will be reported in detail in the next grant period. Less