Preservation of NADH voltammetry for enzyme-modified electrodes based on dehydrogenase.
Preservation of NADH voltammetry for enzyme-modified electrodes based on dehydrogenase.
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DOI：
10.1021/ac980354x
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发表时间：
1999-03
影响因子：
7.4
通讯作者：
M. Hayes;W. Kuhr
中科院分区：
文献类型：
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作者：
M. Hayes;W. Kuhr
最小化过电位和产生高法拉第电流是快速扫描伏安法测定烟酰胺腺嘌呤二核苷酸（NADH）的关键问题，以提高基于辅酶A酶的酶修饰电极的灵敏度。虽然NADH伏安法在固体电极表面表现出高的过电位和差的伏安峰形，但电极表面的修饰可以改善在碳纤维上的电化学响应。然而，这些改进在酶的共价连接后严重退化。本研究的重点是在整个酶连接过程中创建改进的电子转移特性和保留这些特性。开发了一种新的抛光和电化学预处理方法，该方法在碳纤维电极上产生降低的过电位和高法拉第电流。在酶的制造过程中，导致伏安响应的降解的因素进行了研究，老化和共价修饰的预处理表面有助于这种降解。最小化制备时间的附着过程，反过来，最大化保留了容易的电子转移特性。这些附着过程包括改变酶的表面附着反应。减少制备时间的技术包括对现有技术进行建模，然后在可能的情况下改进动力学和传质问题。替代的共价连接方法包括直接电化学胺反应和电化学还原酰肼反应。荧光和电化学研究证实了这些探针的表面附着和保留的电子转移性能。
Minimizing overpotential and generating high faradaic currents are critical issues for fast-scan voltammetry of beta-nicotinamide adenine dinucleotide (NADH) for the sensitivity of enzyme-modified electrodes based on dehydrogenases. Although NADH voltammetry exhibits high overpotential and poor voltammetric peak shape at solid electrode surfaces, modification of the electrode surface can improve the electrochemical response at carbon fibers. However, these improvements are severely degraded upon the covalent attachment of enzyme. The creation of improved electron-transfer properties and the retention of these properties throughout the enzyme attachment process is the focus of this study. A novel polishing and electrochemical pretreatment method was developed which generated a decreased overpotential and a high faradaic current at carbon-fiber electrodes for NADH. Factors that lead to a degradation of voltammetric response during the enzyme fabrication were investigated, and both the aging and the covalent modification of the pretreated surface contributed to this degradation. Attachment processes that minimized the preparation time, in turn, maximized the retention of the facile electron-transfer properties. These attachment processes included varying the surface attachment reactions for the enzyme. Preparation time reduction techniques included modeling existing techniques and then improving kinetic and mass transport issues where possible. Alternate covalent attachment methods included a direct electrochemical amine reaction and an electrochemically reductive hydrazide reaction. The surface attachment and retention of electron-transfer properties of these probes were confirmed by fluorescence and electrochemical studies.