Specific Oxygen-Containing Functional Groups on the Carbon Surface Underlie an Enhanced Sensitivity to Dopamine at Electrochemically Pretreated Carbon Fiber Microelectrodes
Specific Oxygen-Containing Functional Groups on the Carbon Surface Underlie an Enhanced Sensitivity to Dopamine at Electrochemically Pretreated Carbon Fiber Microelectrodes
复制标题
DOI：
10.1021/la9048924
复制
发表时间：
2010-06-01
期刊：
影响因子：
3.9
通讯作者：
Sombers, Leslie A.
中科院分区：
文献类型：
--
作者：
Roberts, James G.;Moody, Benjamin P.;Sombers, Leslie A.
在体内使用碳纤维微电极的神经化学研究已被证明是选择性和灵敏度时，再加上背景扣除快速扫描循环伏安法（FSCV）。已经建立了各种电化学预处理，以提高这些传感器的灵敏度，然而，这些增强策略的基本化学机制仍然知之甚少。我们已经研究了一种电化学预处理，其中从-0.5至1.8 V的扩展三角波形施加到电极之前，使用更标准的波形范围从-0.4至1.3 V的多巴胺的伏安检测。这种预处理增强了电子转移动力学和显着提高灵敏度。为了深入了解化学机理，使用常见的分析技术研究了电极。接触式原子力显微镜（AFM）被用来证明，表面粗糙度没有改变纳米电化学预处理。利用拉曼光谱研究碳表面上的氧化物官能团，并证实通过电化学调节增加了羰基和羟基官能团。这些基团的选择性化学修饰后收集的光谱暗示羟基官能度，而不是羰基，作为增强的电化学信号的主要贡献者。最后，我们已经证明，这种电化学预处理可用于创建碳微盘电极与那些与较大的，常规处理的圆柱形碳纤维微电极相关联的灵敏度。
The in vivo use of carbon-fiber microelectrodes for neurochemical investigation has proven to be selective and sensitive when coupled with background-subtracted fast-scan cyclic voltammetry (FSCV). Various electrochemical pretreatments have been established to enhance the sensitivity of these sensors; however, the fundamental chemical mechanisms underlying these enhancement strategies remain poorly understood. We have investigated an electrochemical pretreatment in which an extended triangular waveform from -0.5 to 1.8 V is applied to the electrode prior to the voltammetric detection of dopamine using a more standard waveform ranging from -0.4 to 1.3 V. This pretreatment enhances the electron-transfer kinetics and significantly improves sensitivity. To gain insight into the chemical mechanism, the electrodes were studied using common analytical techniques. Contact atomic force microscopy (AFM) was used to demonstrate that the surface roughness was not altered on the nanoscale by electrochemical pretreatment. Raman spectroscopy was utilized to investigate oxide functionalities on the carbon surface and confirmed that carbonyl and hydroxyl functional groups were increased by electrochemical conditioning. Spectra collected after the selective chemical modification of these groups implicate the hydroxyl functionality, rather than the carbonyl, as the major contributor to the enhanced electrochemical signal. Finally, we have demonstrated that this electrochemical pretreatment can be used to create carbon microdisc electrodes with sensitivities comparable to those associated with larger, conventionally treated cylindrical carbon fiber microelectrodes.