Enzyme-Modified Carbon-Fiber Microelectrode for the Quantification of Dynamic Fluctuations of Nonelectroactive Analytes Using Fast-Scan Cyclic Voltammetry

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• 作者：Leyda Z. Lugo-Morales ; Philip L. Loziuk ; Amanda K. Corder ; J. Vincent Toups ; James G. Roberts ; Katherine A. McCaffrey ; Leslie A. Sombers
• 刊名：Analytical Chemistry
• 出版年：2013
• 出版时间：September 17, 2013
• 年：2013
• 卷：85
• 期：18
• 页码：8780-8786
• 全文大小：309K
• 年卷期：v.85,no.18(September 17, 2013)
• ISSN：1520-6882

文摘

Neurotransmission occurs on a millisecond time scale, but conventional methods for monitoring nonelectroactive neurochemicals are limited by slow sampling rates. Despite a significant global market, a sensor capable of measuring the dynamics of rapidly fluctuating, nonelectroactive molecules at a single recording site with high sensitivity, electrochemical selectivity, and a subsecond response time is still lacking. To address this need, we have enabled the real-time detection of dynamic glucose fluctuations in live brain tissue using background-subtracted, fast-scan cyclic voltammetry. The novel microbiosensor consists of a simple carbon fiber surface modified with an electrodeposited chitosan hydrogel encapsulating glucose oxidase. The selectivity afforded by voltammetry enables quantitative and qualitative measurements of enzymatically generated H₂O₂ without the need for additional strategies to eliminate interfering agents. The microbiosensors possess a sensitivity and limit of detection for glucose of 19.4 卤 0.2 nA mM^鈥? and 13.1 卤 0.7 渭M, respectively. They are stable, even under deviations from physiological normoxic conditions, and show minimal interference from endogenous electroactive substances. Using this approach, we have quantitatively and selectively monitored pharmacologically evoked glucose fluctuations with unprecedented chemical and spatial resolution. Furthermore, this novel biosensing strategy is widely applicable to the immobilization of any H₂O₂ producing enzyme, enabling rapid monitoring of many nonelectroactive enzyme substrates.