Overoxidized polypyrrole-coated carbon fiber microelectrodes for dopamine measurements with fast-scan cyclic voltammetry
Overoxidized polypyrrole-coated carbon fiber microelectrodes for dopamine measurements with fast-scan cyclic voltammetry
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DOI：
10.1021/ac960153y
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发表时间：
1996-07-01
影响因子：
7.4
通讯作者：
Wightman, RM
中科院分区：
文献类型：
--
作者：
Pihel, K;Walker, QD;Wightman, RM
过度氧化的聚吡咯薄膜已被电化学涂覆在碳纤维微电极上，并在扫描速率为300 V/s的情况下，使用背景减去快速扫描循环伏安法测量多巴胺。只有当电极在pH 7.4的水溶液中扫描到高电位（1400 mV vs SSCE）时，电极表面的膜才稳定。将过度氧化聚吡咯涂层电极上的多巴胺敏感性、抗坏血酸和二羟基苯基乙酸（DOPAC）排斥与涂有全氟离子交换材料Nafion的碳纤维电极上的多巴胺敏感性和排斥进行了比较。在300 V/s下，过氧化聚吡啶包被电极对多巴胺的敏感性几乎是未包被电极的3倍。此外，在体内对抗坏血酸和DOPAC（多巴胺的常见干扰）的反应衰减方面，膜与Nafion一样有效。过度氧化的聚吡咯涂层电极植入大鼠大脑后，对多巴胺保持稳定反应数小时。该电化学沉积方法在椭圆和圆柱形电极上均有效。这与使用Nafion薄膜的浸涂程序形成对比，后者会导致圆柱形电极上的涂层不均匀。
Thin films of overoxidized polypyrrole have been electrochemically coated onto carbon fiber microelectrodes and used for dopamine measurements with background-subtracted, fast-scan cyclic voltammetry at a scan rate of 300 V/s. The films were stable on the electrode surface only when the electrodes were scanned to high potentials (1400 mV vs SSCE) in pH 7.4 aqueous buffer. Dopamine sensitivity and ascorbate and dihydroxyphenylacetic acid (DOPAC) rejection at the overoxidized polypyrrole-coated electrode were compared to those at carbon fiber electrodes coated with Nafion, a perfluorinated ion-exchange material. At 300 V/s, the overoxidized polypyrrole-coated electrode was almost 3 times more sensitive to dopamine than an uncoated disk electrode, Furthermore, the films were as effective as Nafion in the attenuation of the response to ascorbate and DOPAC, common interferences of dopamine in vivo. Overoxidized polypyrrole-coated electrodes maintained a stable response to dopamine for several hours when implanted in the rat brain. The electrochemical deposition procedure was effective at both elliptical and cylindrical electrodes. This is in contrast to the dip-coating procedures employed with Nafion films that lead to nonuniform coatings at cylindrical electrodes.