镀金和碳纳米管修饰金电极上吸附态葡萄糖氧化酶比活性的EQCM研究

采用石英晶体微天平(EQCM)技术监测了裸金电极、镀金和碳纳米管修饰金电极上葡萄糖氧化酶(GOD)的吸附过程. 通过EQCM测量吸附固定的GOD质量, 并实时检测酶反应产物H2O2的氧化电量, 求算了各表面上吸附态GOD的比活性(ESAi). 结果表明, 各表面上均可吸附一定的GOD, 且吸附态GOD均有一定的酶活性; 修饰CNTs可增大酶吸附量和酶电极对葡萄糖的响应电流, 但ESAi随CNTs修饰量的增大而降低; Au电极上电镀金后, 酶吸附量和酶电极对葡萄糖的响应电流亦增大, 但ESAi与裸金电极上的基本一致.

EQCM Studies on Enzymatic Specific Activities of Glucose Oxidase Adsorbed on Au-electroplated and Carbon Nanotubes-modified Au Electrodes

The electrochemical quartz crystal microbalance (EQCM) technique was employed to monitor in situ the adsorption of glucose oxidase (GOD) onto bare Au, Au-electroplated, and carbon nanotubes(CNTs)-modified Au electrodes. The enzymatic specific activities (ESAi) for GOD adsorbed on various surfaces were measured from the mass of adsorbed GOD obtained via EQCM characterization and the charge for oxidation of enzymatically generated H2O2. The results showed that GOD could adsorb on the investigated surfaces with different adsorption amounts, and the adsorbed GOD was enzymatically active to some degree; the modification of CNTs increased the adsorption amount of GOD and the response current to glucose, but the ESAi decreased with the increase of the amount of modified CNTs; the Au electroplating on Au electrode also increased the response current to glucose, but the ESAi changed little after the electroplating.