pH-Switchable Bioelectrocatalysis of Hydrogen Peroxide on Layer-by-Layer Films Assembled by Concanavalin A and Horseradish Peroxidase with Electroactive Mediator in Solution

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• 作者：Huiqin Yao ; Naifei Hu
• 刊名：Journal of Physical Chemistry B
• 出版年：2010
• 出版时间：March 11, 2010
• 年：2010
• 卷：114
• 期：9
• 页码：3380-3386
• 全文大小：225K
• 年卷期：v.114,no.9(March 11, 2010)
• ISSN：1520-5207

文摘

The lectin protein concanavalin A (Con A) and the glycoenzyme horseradish peroxidase (HRP) were assembled into {Con A/HRP}_n layer-by-layer films on electrodes mainly by biospecific affinity between them. The cyclic voltammetric (CV) response of ferricyanide (Fe(CN)₆³⁻) at {Con A/HRP}_n film electrodes was very sensitive to the environmental pH. The peak currents of Fe(CN)₆³⁻ were quite large at pH 4.0 but greatly suppressed at pH 9.0, demonstrating reversible pH-sensitive “on−off” behavior. This property could be used to realize pH-controlled electrochemical reduction of H₂O₂ catalyzed by HRP immobilized in {Con A/HRP}_n films and mediated by Fe(CN)₆³⁻ in solution. The modulation of the solution pH was also realized by in situ biochemical reactions with various enzymes in solution and was used to tune the pH-switchable bioelectrocatalysis. The possible mechanism of the pH-responsive on−off behavior of the films toward the probe was explored, and the electrostatic interaction between the films and the probe is believed to play a key role in deciding the pH-sensitive behavior of the films. This “smart” interface may be used to establish a foundation for fabricating novel pH-controllable electrochemical biosensors based on bioelectrocatalysis with immobilized enzymes.