Bioelectrochemical-Array Sensor Using DNA Conjugate as Chemical Sensing Element

本研究项目涉及1)酶法合成聚对苯二酚，2)化学修饰电极的制备和基因传感器的应用，3)DNA微阵列的扫描电化学显微镜成像。首先，我们通过酶法氧化Albutin合成了氧化还原聚合物，形成了聚对苯二酚糖苷衍生物，然后通过化学去除糖保护基团将其转化为PQ。然后将聚合物应用于具有单链寡核苷酸(ODN)/PQ表面结构的DNA偶联修饰电极。电化学研究表明，该电极通过改变其氧化还原活性来响应表面锚定的ODN的杂交。通过对电化学和生物亲和反应的详细研究，认为DNA偶联修饰电极是一种能够检测特定基因的电化学传感器。作为高通量分析设备开发的起点，我们尝试用SECM对DNA共轭电极的比电化学活性进行二维成像。我们最终成功地实现了1)DNA微点(20微米)的2D成像和2)通过监测微点的氧化还原活性通过2D成像检测DNA杂交。

This research project has involved 1)enzymic synthesis of poly(hydroquinone), PQ, 2)chemically modified electrode preparations and gene sensor applications, and finally, 3)scanning electrochemical microscopic(SECM) imaging of DNA microarray. First, we synthesized the redox polymer by enzymic oxidation of albutin to form poly(hydroquinone glycoside) derivative, which was subsequently converted to PQ by chemical removal of the sugar-protecting group. The polymer was then applied to DNA-conjugate modified electrode having a single-stranded oligodeoxyribonucleotide (ODN)/PQ surface structure. Electrochemical studies showed that the electrode was responsive to the hybridization of the surface-anchored ODN by changing its redox activity. By detailed studied on the electrochemistry and the bioaffinity reaction, the DNA-conjugate modified electrode was concluded to be a candidate of electrochemical sensor capable of detection of specific genes. As the start point of high-throughput analytical device development, we made an attempt of two-dimensional imaging of the specific electrochemical activity of the DNA conjugate electrode using a SECM. We have finally succeeded 1)2D imaging of the DNA microdots (20 micron) and 2)detection of DNA hybridization through 2D imaging by monitoring the redox activity of the microdot.