Ohgami Naoto, Upadhyay Sanjay, Kabata Ayumi, Morimoto Katsuya, Kusakabe Hitoshi, Suzuki Hiroaki
Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan.
Biosens Bioelectron. 2007 Feb 15;22(7):1330-6. doi: 10.1016/j.bios.2006.06.007. Epub 2006 Jul 18.
A microfluidic system for the analysis of the activities of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) was fabricated. The device consists of a glass chip with a micro-electrochemical L-glutamate sensor and a polydimethylsiloxane (PDMS) sheet with a Y-shaped micro-flow channel. A sample solution and a substrate solution for the enzymes were introduced from two injection ports at the end of the flow channel. When the flows were stopped, substrates in a solution mixed immediately with either of the enzymes by diffusion in a mixing channel. L-glutamate produced by the enzymatic reaction of GOT or GPT in the flow channel was detected by using the L-glutamate sensor. A distinct current increase was observed immediately after mixing, and the initial slope of the response curve varied in proportion to the activity of GOT or GPT. The relation between the slope of the response curve and the enzyme activity was linear between 7 and 228 U l-1 for GOT and 9 and 250 U l-1 for GPT. The quality of the response curve was improved with an increase in the channel height. The measurement based on the rate analysis in the micro-flow channel facilitated the reduction of the influence of interferents. The influence of the viscosity of the sample solution was also checked for the analysis of real samples. The determination of the enzyme activities was also conducted in a system with micropumps fabricated for a sample injection. Two solutions could be mixed in the mixing channel, and the activity of the enzymes could be measured as in the experiments using microsyringe pumps.
制备了一种用于分析谷草转氨酶（GOT）和谷丙转氨酶（GPT）活性的微流控系统。该装置由一个带有微电化学L-谷氨酸传感器的玻璃芯片和一个带有Y形微流通道的聚二甲基硅氧烷（PDMS）片组成。酶的样品溶液和底物溶液从流道末端的两个进样口引入。当流动停止时，溶液中的底物通过在混合通道中的扩散立即与两种酶中的任一种混合。使用L-谷氨酸传感器检测流道中GOT或GPT酶促反应产生的L-谷氨酸。混合后立即观察到明显的电流增加，响应曲线的初始斜率与GOT或GPT的活性成比例变化。对于GOT，响应曲线的斜率与酶活性之间的关系在7至228 U l-1之间呈线性，对于GPT，在9至250 U l-1之间呈线性。随着通道高度的增加，响应曲线的质量得到改善。基于微流道中速率分析的测量有助于减少干扰物的影响。还检查了样品溶液粘度对实际样品分析的影响。酶活性的测定也在一个为样品注射制造的带有微型泵的系统中进行。两种溶液可以在混合通道中混合，并且可以像使用微型注射器泵的实验一样测量酶的活性。
