Direct electron transfer of glucose oxidase promoted by carbon nanotubes
Direct electron transfer of glucose oxidase promoted by carbon nanotubes
复制标题
DOI：
10.1016/j.ab.2004.05.057
复制
发表时间：
2004-09-01
影响因子：
2.9
通讯作者：
Chen, J
中科院分区：
文献类型：
--
作者：
Cai, CX;Chen, J
通过将碳纳米管（CNT）分散在表面活性剂如十六烷基三甲基溴化铵（CTAB，阳离子表面活性剂）的溶液中获得碳纳米管（CNT）的稳定悬浮液。碳纳米管（分散在0.1%CTAB溶液中）对固定在碳纳米管表面的葡萄糖氧化酶（GOx）的直接电子转移有促进作用。将GOx固定在碳纳米管表面后，其直接电子转移速率大大提高。在磷酸盐缓冲溶液（PBS，pH6.9）中，循环伏安法显示出一对边界清晰的氧化还原峰，对应于GOx的直接电子转移，其中点电位约为-0.466 V（vsSCE（饱和甘汞电极））。估算了表观非均相电子转移速率常数（k（s））和中点电位（E-1/2）等电化学参数。E-1/2对溶液pH的依赖性表明，GOx的直接电子转移反应是一个双电子转移与双质子转移耦合的反应过程。实验结果还表明，固定的GOx保留其生物电催化活性的葡萄糖的氧化，这表明电极可能会发现在生物传感器（例如，它可以用作生物燃料电池中的生物阳极）的用途。本文提出的方法可以很容易地扩展到其他氧化还原酶或蛋白质的直接电化学研究。(C)2004年爱思唯尔公司All rights reserved.
A stable suspension of carbon nanotubes (CNT) was obtained by dispersing the CNT in a solution of surfactant, such as cetyltrimethylammonium bromide (CTAB, a cationic surfactant). CNT (dispersed in the solution of 0.1% CTAB) has promotion effects on the direct electron transfer of glucose oxidase (GOx), which was immobilized onto the Surface of CNT. The direct electron transfer rate of GOx was greatly enhanced after it was immobilized onto the surface of CNT. Cyclic voltammetric results showed a pair of well-defined redox peaks, which corresponded to the direct electron transfer of GOx, with a midpoint potential of about -0.466 V (vs SCE (saturated calomel electrode)) in the phosphate buffer solution (PBS, pH 6.9). The electrochemical parameters such as apparent heterogeneous electron transfer rate constant (k(s)) and the value of midpoint potential (E-1/2) were estimated. The dependence Of E-1/2 on solution pH indicated that the direct electron transfer reaction of GOx is a two-electron-transfer coupled with a two-proton-transfer reaction process. The experimental results also demonstrated that the immobilized GOx retained its bioelectrocatalytic activity for the oxidation of glucose, suggesting that the electrode may find use in biosensors (for example, it may be used as a bioanode in biofuel cells). The method presented here can be easily extended to immobilize and obtain the direct electrochemistry of other redox enzymes or proteins. (C) 2004 Elsevier Inc. All rights reserved.