A Key Laboratory of Theoretical Organic Chemistry and Functional Molecule of Ministry of Education, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan, Hunan 411201, P. R. China.
School of Chemistry and Molecular Engineering, Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, East China Normal University, 500 Dongchuan Road, Shanghai 200241, P. R. China.
Anal Chem. 2020 Mar 3;92(5):3981-3989. doi: 10.1021/acs.analchem.9b05484. Epub 2020 Feb 20.
The in vivo monitoring of ascorbic acid (AA) following physiological and pathological events is of great importance because AA plays a critical role in brain functions. The conventional electrochemical sensors (ECSs) usually suffered from poor selectivity and sluggish electron transfer kinetics for cerebral AA oxidation. The exploitation of ECSs adapt to the electrochemical detection (ECD)-microdialysis system, here we reported a facile ratiometric electrochemical sensor (RECS) for in vivo/online repetitive measurements of cerebral AA in brain microdiaysate. The sensor were constructed by careful electrodeposition of graphene oxide (GO) onto glassy carbon (GC) electrodes. Methylene blue (MB) was electrostatically adsorbed onto the GO surface as a built-in reference to achieve ratiometric detection of AA. The subsequent proper electroreduction treatment was able to readily facilitate the oxidation of AA at a relatively negative potential (-100 mV) and the oxidation of MB at separated potential (-428 mV). The in vitro experiments demonstrated that the RECS exhibited high sensitivity (detection limit: 10 nM), selectivity, and stability toward AA determination, enabling the in vivo/online repetitive measurement of cerebral AA in brain microdiaysate with high reliability. As a result, the designed RECS was successfully applied in the ECD-microdialysis system to in vivo/online repetitive monitoring the dynamic change of cerebral AA in the progress of the global cerebral ischemia/reperfusion events. More, the microinjection of endogenous AA and AA oxidase (AAOx) verified the reliability of the proposed RECS for in vivo/online repetitive cerebral AA detection. This proposed sensor filled the gap that no rational electrochemical sensor has been developed for the ECD-microdialysis system since its creation by the Mao group in 2005, which provided a reliable and effective method for brain chemistry research.
在生理和病理事件后对抗坏血酸（AA）进行体内监测非常重要，因为 AA 在大脑功能中起着关键作用。传统的电化学传感器（ECS）通常由于对脑 AA 氧化的选择性差和电子转移动力学缓慢而受到限制。开发适应电化学检测（ECD）-微透析系统的 ECS 时，我们在这里报道了一种用于在脑微透析物中进行体内/在线重复测量脑 AA 的简便比率型电化学传感器（RECS）。该传感器通过仔细将氧化石墨烯（GO）电沉积到玻碳（GC）电极上构建而成。亚甲蓝（MB）静电吸附到 GO 表面上作为内置参比，以实现 AA 的比率型检测。随后进行适当的电还原处理，能够在相对负的电位（-100 mV）下容易地促进 AA 的氧化，以及在分离的电位（-428 mV）下促进 MB 的氧化。体外实验表明，RECS 对 AA 测定具有高灵敏度（检测限：10 nM）、选择性和稳定性，能够在脑微透析物中进行体内/在线重复测量脑 AA，具有高度可靠性。结果，所设计的 RECS 成功地应用于 ECD-微透析系统中，用于在全脑缺血/再灌注事件过程中进行体内/在线重复监测脑 AA 的动态变化。此外，内源性 AA 和 AA 氧化酶（AAOx）的微注射验证了所提出的 RECS 用于体内/在线重复检测脑 AA 的可靠性。该传感器填补了自 2005 年 Mao 小组创建 ECD-微透析系统以来，尚无合理的电化学传感器用于该系统的空白，为脑化学研究提供了可靠有效的方法。
