Dopamine (DA) signaling is critically important in striatal function, and this metabolically demanding process is fueled largely by glucose. However, DA and glucose are typically studied independently and, as such, the precise relationship between DA release and glucose availability remains unclear. Fast-scan cyclic voltammetry (FSCV) is commonly coupled with carbon-fiber microelectrodes to study DA transients. These microelectrodes can be modified with glucose oxidase (GOx) to generate microbiosensors capable of simultaneously quantifying real-time and physiologically relevant fluctuations of glucose, a nonelectrochemically active substrate, and DA, which is readily oxidized and reduced at the electrode surface. A chitosan hydrogel can be electrodeposited to entrap the oxidase enzyme on the sensor surface for stable, sensitive, and selective codetection of glucose and DA using FSCV. This strategy can also be used to entrap lactate oxidase on the carbon-fiber surface for codetection of lactate and DA. However, these custom probes are individually fabricated by hand, and performance is variable. This study characterizes the physical nature of the hydrogel and its effects on the acquired electrochemical data in the detection of glucose (2.6 mM) and DA (1 μM). The results demonstrate that the electrodeposition of the hydrogel membrane is improved using a linear potential sweep rather than a direct step to the target potential. Electrochemical impedance spectroscopy data relate information on the physical nature of the electrode/solution interface to the electrochemical performance of bare and enzyme-modified carbon-fiber microelectrodes. The electrodeposition waveform and scan rate were characterized for optimal membrane formation and performance. Finally, codetection of both DA/glucose and DA/lactate was demonstrated in intact rat striatum using probes fabricated according to the optimized protocol. Overall, this work improves the reliable fabrication of carbon-fiber microbiosensors for codetection of DA and important energetic substrates that are locally delivered to the recording site to meet metabolic demand.

中文翻译：

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用于脑组织中葡萄糖和多巴胺联合检测的碳纤维微生物传感器的优化制造


多巴胺 (DA) 信号传导对于纹状体功能至关重要，而这种代谢过程需要大量葡萄糖来推动。然而，DA 和葡萄糖通常是独立研究的，因此，DA 释放和葡萄糖可用性之间的精确关系仍不清楚。快速扫描循环伏安法 (FSCV) 通常与碳纤维微电极结合来研究 DA 瞬态。这些微电极可以用葡萄糖氧化酶 (GOx) 进行修饰，以生成能够同时量化葡萄糖（一种非电化学活性底物）和 DA 的实时和生理相关波动的微生物传感器，DA 很容易在电极表面氧化和还原。可以电沉积壳聚糖水凝胶以将氧化酶捕获在传感器表面上，从而使用 FSCV 对葡萄糖和 DA 进行稳定、灵敏和选择性的共检测。该策略还可用于在碳纤维表面捕获乳酸氧化酶，以共同检测乳酸和 DA。然而，这些定制探针是单独手工制造的，并且性能各不相同。本研究表征了水凝胶的物理性质及其对检测葡萄糖 (2.6 mM) 和 DA (1 μM) 时获得的电化学数据的影响。结果表明，使用线性电位扫描而不是直接步进到目标电位可以改善水凝胶膜的电沉积。电化学阻抗谱数据将电极/溶液界面的物理性质信息与裸碳纤维微电极和酶改性碳纤维微电极的电化学性能联系起来。表征电沉积波形和扫描速率以获得最佳的膜形成和性能。 最后，使用根据优化方案制造的探针在完整的大鼠纹状体中证明了 DA/葡萄糖和 DA/乳酸的共同检测。总体而言，这项工作改进了碳纤维微生物传感器的可靠制造，用于共同检测 DA 和重要的能量底物，这些底物被本地传送到记录位点以满足代谢需求。