Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University , North Zhongshan Road 3663, Shanghai, 200062, P. R. China.
State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science and Laboratory of Advanced Materials, and Department of Chemistry, Fudan University , Shanghai, 200433, P. R. China.
Anal Chem. 2017 Feb 7;89(3):1831-1837. doi: 10.1021/acs.analchem.6b04168. Epub 2017 Jan 13.
Ascorbic acid (AA) levels are closely correlated with physiological and pathological events in brain diseases, but the mechanism remains unclear, mainly due to the difficulty of accurately analyzing AA levels in live brain. In this study, by engineering tunable defects and oxygen-containing species in carbon nanotubes, a novel aligned carbon nanotube fiber was developed as an accurate microsensor for the ratiometric detection of AA levels in live rat brains with Alzheimer's disease (AD). AA oxidation is greatly facilitated on the fiber surface at a low potential, leading to high sensitivity as well as high selectivity against potential sources of interference in the brain. Additionally, an unexpected, separate peak from the fiber surface remains constant as the AA concentration increases, enabling real-time and ratiometric detection with high accuracy. The results demonstrated that the AA levels were estimated to be 259 ± 6 μM in cortex, 264 ± 20 μM in striatum, and 261 ± 21 μM in hippocampus, respectively, in normal condition. However, the overall AA level was decreased to 210 ± 30 μM in cortex, 182 ± 5 μM in striatum, and 136 ± 20 μM in hippocampus in the rat brain model of AD. To the best of our knowledge, this work is the first to accurately detect AA concentrations in the brains of live animal model of AD.
抗坏血酸（AA）水平与脑部疾病的生理和病理事件密切相关，但机制尚不清楚，主要是因为难以准确分析活脑中的 AA 水平。在这项研究中，通过工程化调控碳纳米管中的可调缺陷和含氧物种，开发了一种新型的定向碳纳米管纤维，作为一种精确的微传感器，用于实时和比率检测阿尔茨海默病（AD）大鼠活脑中的 AA 水平。在低电势下，纤维表面上的 AA 氧化大大得到促进，从而具有高灵敏度和对大脑中潜在干扰源的高选择性。此外，从纤维表面分离出的一个意想不到的独立峰随着 AA 浓度的增加而保持不变，从而实现了高准确性的实时和比率检测。结果表明，正常情况下，皮层中的 AA 水平估计为 259±6 μM，纹状体中的 AA 水平为 264±20 μM，海马体中的 AA 水平为 261±21 μM。然而，在 AD 大鼠脑模型中，皮层中的 AA 总水平下降到 210±30 μM，纹状体中的 AA 水平下降到 182±5 μM，海马体中的 AA 水平下降到 136±20 μM。据我们所知，这是首次准确检测 AD 动物模型活脑中的 AA 浓度。
