Fabrication and Evaluation of Enzyme Switches

本计画的目的是制作以酵素的特定催化能力为基础而运作的锯齿状酵素开关。在整个项目中取得了以下成果。通过电聚合吡咯将心肌黄酶（Dp）和葡萄糖氧化酶（GOD）固定在电极表面。固定化酶电极的伏安行为表明，这些酶保持其活性。本文提出了一种测定酶反应动力学参数的电化学方法。对参数的详细分析表明，Dp的活性中心具有疏水性.研究了交叉指型微阵列电极（Au、Pt或ITO ;电极和间隙宽度，4- 20 μ m）在静止和流动条件下的电化学行为。阵列电极具有放大氧化还原循环电流响应的能力，并且它们的行为可以通过数字模拟来预测。氧化还原聚合物涂层的阵列电极具有开关特性.在此基础上，将含Dp的吡咯/N-甲基吡咯共聚物电化学涂覆在微阵列电极上，制备了酶传感器。加入Dp的底物NADH，通过酶反应将阵列表面的聚合物还原至绝缘状态。因此，该阵列器件在NADH的作用下表现出开关特性。用十八烷基三乙氧基硅烷处理阵列电极使表面疏水;这个过程对于在间隙区域获得这种聚合物形成和快速开关响应是必不可少的。

The purpose pf the present project is to fabricate enbricate enzyme switches which operate based on the specific catalytic capability of enzymes. The following results are obtained throughout this project.1. Diaphorase (Dp) and glucose oxidase (GOD) were immobilized on electrode surfaces by electropolymerization of pyrroles. Voltammetric behavior the enzyme-immobilized electrodes indicated that these enzymes remained their activity. We have proposed a new electrochemical method for determination of various kinetic parameters of the enzyme reactions. A detailed analysis of the parameters suggested that active center of Dp is hydrophobic.2. The electrochemical behavior of interdigitated microarray electrodes (Au, Pt, or ITO ; eletrode and gap widths, 4-20mum) was investigated in stationary and flowing conditions. The array eletrodes have capabilities of magnifying the current responses due to redox cycling and their behavior can be predicted by the digital simulation. The array electrodes coated with redox polymers exhibit switch-like characteristics.3. Based on the above results, an enzyme device was fabricated by the eletrochemical coating pyrrole/N-methylpyrrole copolymer containing Dp on the microarray electrodes. The addition of NADH, a substrate for Dp, resulted in reduction of the polymer on the array surface to insulating state through the enzyme reaction. Therefore, the array device exhibited the on-off switching characteristics upon of NADH. The treatment of array electrode with octadecyltriethoxysilane made the surface hydrophobic ; this process is essential to obtain this polymer formation at gap area and rapid switching responses.