Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials and Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, P. R. China.
Analyst. 2017 May 2;142(9):1452-1458. doi: 10.1039/c7an00138j.
Nitric oxide (NO) is key free-radical messenger and neuronal signal which is closely related to many brain diseases. It is a challenge to develop a sensitive and reliable biosensor for in vivo monitoring of NO in the brain. In this research, a simple ratiometric electrochemical biosensor for NO monitoring in rat brain following cerebral ischemia was developed using a carbon nanotube fiber (CNF) modified with hemin, in which the CNF not only served as a platform to assemble the hemin molecule, but greatly facilitated the electron transfer of hemin on to the electrode surface. Additionally, the hemin molecule was found to play dual roles: as a stable catalyst for the reduction of NO for selective detection of NO at -0.67 V versus silver/silver chloride, as well as an inner reference element to provide a built-in correction, to avoid the interference from the complicated brain environment. The developed ratiometric biosensor can detect NO with a linear range from 25 to 1000 nM, with a low limit of detection down to 10 nM, which fulfills the requirements for in vivo measurement of NO. The remarkable analytical performance of the present biosensor, as well as the long-term stability and good reproducibility established this as a reliable approach for in vivo monitoring of NO in the hippocampus of rat brains following cerebral ischemia. This is the first report that the average level of NO increased from 61 ± 23 nM to 141 ± 18 nM after cerebral ischemia for 15 min.
一氧化氮（NO）是一种关键的自由基信使和神经元信号分子，与许多脑部疾病密切相关。开发一种用于体内监测大脑中 NO 的敏感可靠的生物传感器是一个挑战。在这项研究中，我们使用经过血红素修饰的碳纳米纤维（CNF）开发了一种用于监测大鼠脑缺血后 NO 的简单比率型电化学生物传感器，其中 CNF 不仅作为组装血红素分子的平台，而且极大地促进了血红素在电极表面的电子转移。此外，血红素分子被发现具有双重作用：作为还原 NO 的稳定催化剂，用于在相对于银/氯化银 -0.67 V 处选择性检测 NO，以及作为内参元素提供内置校正，以避免复杂的大脑环境的干扰。所开发的比率型生物传感器可检测 25 至 1000 nM 范围内的 NO，检测下限低至 10 nM，满足体内测量 NO 的要求。本生物传感器具有出色的分析性能，以及长期稳定性和良好的重现性，为在脑缺血后大鼠海马体中进行体内监测 NO 提供了一种可靠的方法。这是首次报道脑缺血 15 分钟后，NO 的平均水平从 61 ± 23 nM 增加到 141 ± 18 nM。
