固载于壳聚糖-纳米金复合膜修饰玻碳电极上的葡萄糖氧化酶的直接电化学研究及其生物传感应用

通过将葡萄糖氧化酶固载于壳聚糖-纳米金复合膜内所构置的传感器，实现了葡萄糖氧化酶的直接电化学，并采用循环伏安法与电化学阻抗法对修饰电极进行了表征。研究表明：在除氧缓冲溶液中，葡萄糖氧化酶-壳聚糖-纳米金复合膜修饰电极表现出一对良好的氧化还原峰，这对峰归因于葡萄糖氧化酶的氧化还原，证明葡萄糖氧化酶被成功固载于复合膜内。电子传递速率常数为15.6 s-1,说明葡萄糖氧化酶的电活性中心与电极之间的电子传递很快。将壳聚糖与纳米金相结合还提高了葡萄糖氧化酶在复合膜内的稳定性并保持其生物活性，并可以用于葡萄糖检测。计算得到其表观米氏常数为10.1 mmol·L-1。而且，该生物传感器可以用于血样中葡萄糖含量的测定。

Direct Electrochemistry of Glucose Oxidase Immobilized on Chitosan‐gold Nanoparticle Composite Film on Glassy Carbon Electrodes and Its Biosensing Application

The direct electrochemistry of glucose oxidase (GOx) immobilized on a composite matrix based on chitosan (CHIT) and Au nanoparticles (Au NP) underlying on a glassy carbon electrode was achieved. The cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the modified electrode. In deaerated buffer solutions, the cyclic voltammetry of the composite films of GOx-Au NP-CHIT showed a pair of well-behaved redox peaks that were assigned to the redox reaction of GOx, confirming the effective immobilization of GOx on the composite film. The electron transfer rate constant was estimated to be 15.6 s⁻¹, indicating a high electron transfer between the GOx redox center and electrode. The combination of CHIT and Au NP also promoted the stability of GOx in the composite film and retained its bioactivity, which might have the potential application to glucose determination. The calculated apparent Michaelis-Menten constant was 10.1 mmol·L⁻¹. Furthermore, the proposed biosensor could be used for the determination of glucose in human plasma samples.