微过氧化物酶-11在碳纳米管/壳聚糖修饰电极上的直接电化学及电催化(英文)  

Direct electrochemistry and electrocatalytic activity of microperoxidase-11 immobilized on chitosan wrapped single-walled carbon nanotubes

作　　者：姜慧君[1,2] Philippe Mercier Shiunchin C. Wang 杜翀[1] 李晓伟[1] 杨辉[1] Daniel L.Akins 

机构地区：[1]中国科学院上海微系统与信息技术研究所,上海200050 [2]南京医科大学药学院,南京210029 [3]CASI and Department of Chemistry,The City College of The City University of New York

出　　处：《功能材料与器件学报》2009年第2期132-142,共11页Journal of Functional Materials and Devices

基　　金：the National Natural Science Foundation of China(No.20673136,20706056);the National"863"High-Technology Research Program of China(2006AA05Z136,2007AA05Z141);the 100 People Plan Program of the Chinese Academy of Sciences and the Pujiang Program of Shanghai City(No.06PJ14110) for support of this work

摘　　要：采用一步法于室温下有选择性地将小管径的单壁碳纳米管(SWCNTs)分散于生物相容性的聚合物——壳聚糖的水溶液中,并将其滴涂于玻碳电极表面,制备出微过氧化物酶-11(MP-11)修饰电极。循环伏安结果表明SWCNT促进了MP-11在电极表面的直接电子传递,在pH=7.2的磷酸缓冲溶液中,MP-11的式电位为-0.36V(vs.SCE),MP-11在电极表面的直接电子转移表观速率常数和覆盖度分别为78s-1和8.76×10-10mol.cm-2。进一步的研究结果显示,固定在SWCNT表面的MP-11能保持其对氧气和过氧化氢还原的生物电催化活性,适合用作生物燃料电池的阴极和过氧化氢传感器。氧气在该修饰电极上的还原经历一个四电子过程;该过氧化氢生物传感器对过氧化氢还原的检测具有响应灵敏度高(响应时间小于4s),检测线性范围为2.5×10-6～7.0×10-5μM,检测限为0.8μM,相应的米氏常数和检测灵敏度分别为1.0mMand22.4μA/mM。One- step aqueous dispersion and diameter -selective separation of HiPco single -walled carbon nanotubes （SWCNTs） has been accomplished through noncovalent complexation of the nanotubes with a water -soluble, biocompatible polymer chitosan （CHI） at room temperature. ＂Smaller -diameter＂ SWCNTs are preferentially dispersed and wrapped by CHI in the aqueous supernatant that results following noncentrifuged precipitation, while ＂larger- diameter＂ SWCNTs exist in the precipitate. Such CHI wrapped small -diameter individual SWCNTs have been used for the immobilization of microperoxidase - 11 （MP - 11 ） for direct electrochemistry and electrocatalytic purposes. We found that SWCNTs facilitate the direct electron transfer be- tween MP -11 and the electrode surface, with a formal potential of MP -11 at about -0.36 V （vs. SCE） in phosphate buffer solution （pH 7.2）. The heterogenous electron transfer rate constant and surface coverage of MP- 11 are estimated to be 78 s^-1 and 8.76 × 10^-10 mol/cm^2, respectively. Further study demonstrates that the modified electrode retains its electrocatalytic activity toward the reduction of both O2 and n2O2. The immobilized MP- 11 can catalyze O2 through a four -electron process to water, which could be used as a cathode in a bio fuel cell. Such SWCNT based biosensor exhibits a rapid response time, of less than 4 s, and a good linear detection range for H2O2 concentration, from 2.5 μM to 70 μM with a detection limit of 0. 8 μM. The apparent Michaelis -Menten constant （Km ） and the maximum electrode sensitivity （im=/Km ） are evalua- ted to be 1.0 mM and 22.4 μA/mM, respectively.

关 键 词：微过氧化物酶-11 单壁碳纳米管 壳聚糖 直接电化学 电催化 

分 类 号：O441.4[理学—电磁学]