Electrodeposition of Carbon Nanotubes-Chitosan-Glucose Oxidase Biosensing Composite Films Triggered by Reduction of p-Benzoquinone or H2O2

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• 作者：Qingmei Zhou ; Qingji Xie ; Yingchun Fu ; Zhaohong Su ; Xue'en Jia ; Shouzhuo Yao
• 刊名：Journal of Physical Chemistry B
• 出版年：2007
• 出版时间：September 27, 2007
• 年：2007
• 卷：111
• 期：38
• 页码：11276 - 11284
• 全文大小：393K
• 年卷期：v.111,no.38(September 27, 2007)
• ISSN：1520-5207

文摘

We report here on the electroreduction of p-benzoquinone (BQ) or H₂O₂ as a new trigger for simple, fast,uniform, and controllable electrodeposition of chitosan (CS) hydrogels and biosensing nanocomposite filmsof CS, multiwalled carbon nanotubes (MWCNTs), and glucose oxidase (GOD). The multiparameterelectrochemical quartz crystal microbalance (EQCM) based on crystal electroacoustic impedance analysiswas used to dynamically monitor the deposition processes. When the EQCM Au electrode was immersed ina weakly acidic solution (here pH 5.1 acetic buffer) containing BQ (or H₂O₂) and CS, the proton consumptionduring BQ (or H₂O₂) electroreduction increased the local solution pH near the electrode surface and led tothe deposition of CS hydrogel on the electrode surface at local pH near and above the pK_a value of CS. Theconcentration of BQ (or H₂O₂) required for CS electrodeposition was theoretically evaluated based on anelectrogenerated base-to-acid titration model and supported by experiments. Co-deposition of GOD andMWCNTs with the CS hydrogel was achieved, and the resulting MWCNTs-CS-GOD nanocomposite filmswere demonstrated for glucose biosensing. The MWCNTs-CS-GOD enzyme electrode prepared by BQreduction exhibited a current sensitivity of 6.7 A mM^-1 cm^-2 to glucose, and the linear range for glucosedetection at 0.7 V vs SCE was from 5 M to 8 mM, with a detection limit of 2 M and a Michaelis-Mentenconstant of 6.8 mM. The BQ-electroreduction protocol exhibited the best sensor performance, as comparedwith H₂O₂-reduction and previously reported water-reduction values. The present protocol via electroreductionof a deliberately added oxidant that is accompanied by a local pH change is highly recommended for widerapplications in pH-dependent deposition of other films.