Kawagoe J L, Niehaus D E, Wightman R M
Department of Chemistry, University of North Carolina, Chapel Hill 27599-3290.
Anal Chem. 1991 Dec 15;63(24):2961-5. doi: 10.1021/ac00024a029.
A miniaturized enzyme-modified electrode has been constructed and evaluated. The tip of a capillary-encased, carbon-fiber electrode is recessed, and tetrathiafulvalene-tetracyanoquinodimethane crystals are electrochemically deposited in the recessed tip. Flavoenzymes are placed in the recess by cross-linking with glutaraldehyde. The specific enzymes used are glucose oxidase to form a microbiosensor for glucose, and a combination of acetylcholine esterase and choline oxidase to form a microbiosensor for acetylcholine. The sensor is operated in an amperometric mode with Eapp = 150 mV versus a sodium saturated calomel electrode, and the response appears to be limited by the kinetics of the enzyme reaction. The effective maximum current density for the glucose electrode is greater than 600 microA/cm2. At low concentrations of glucose, oxygen provides a significant interference by attenuating the signal. The device is simple to prepare and has a rapid response time. Interference from ascorbate has been significantly reduced by the design and by addition of a layer of ascorbate oxidase. Although not yet suitable for use in tissue, the biosensors are suitable for detection in situations where oxygen concentrations do not frequently change.
一种小型化酶修饰电极已被构建并评估。毛细管包裹的碳纤维电极尖端有凹陷，四硫富瓦烯 - 四氰基喹啉二甲烷晶体通过电化学沉积在凹陷尖端。通过与戊二醛交联将黄素酶置于凹陷处。所使用的特定酶为葡萄糖氧化酶，用于形成葡萄糖微生物传感器；以及乙酰胆碱酯酶和胆碱氧化酶的组合，用于形成乙酰胆碱微生物传感器。该传感器在安培模式下运行，相对于饱和甘汞电极的外加电压Eapp = 150 mV，响应似乎受酶反应动力学限制。葡萄糖电极的有效最大电流密度大于600 μA/cm²。在低浓度葡萄糖时，氧气通过衰减信号产生显著干扰。该装置制备简单且响应时间快。通过设计以及添加一层抗坏血酸氧化酶，抗坏血酸的干扰已显著降低。尽管该生物传感器尚未适用于组织，但适用于氧气浓度不频繁变化的情况的检测。
