Electrochemical/Optical Nanoprobes for High-Resolution Chemical Analysis at Neuronal Microenvironment

该奖项支持开发一种结合近场扫描光学显微镜（NSOM）和扫描电化学显微镜（SECM）的仪器，其目标是定位单个神经元表面的特定化学物质。 中枢神经系统中的信号传递是由特定的化学信使介导的;因此，测量神经元微环境中化学物质的浓度分布对于提高对神经传递和脑功能的理解至关重要。由于信号事件发生在高度局部化的区域，其尺寸小于几百纳米，因此常用的电化学和光学技术受到电极尺寸（1微米）和光波长的限制。此外，神经过程是高度复杂的化学事件，因此经常需要通过两种或多种技术的组合来同时监测各种分析物。 然而，同步的时空分辨率的技术，是如此困难，所观察到的事件通常缺乏一一对应。 所采取的方法将通过开发既可用作光源又可用作电极的纳米探针来克服这些困难。多功能性允许在同一时间和同一位置进行电化学和光学测量。该项目探索使用选择性蚀刻光纤作为电化学/光学纳米探针的基础。蚀刻技术允许可再现地制造具有小于10 nm的尖端直径的光纤。通过利用尖锐的纤维，电化学/光学纳米探针的直径为100 nm的活性区域将被设计和构建。 一旦构建，将使用探针-样品距离的电化学调节测试尖端的单个神经元囊泡的近场光学成像。该项目将为本科生和研究生在跨学科环境中的培训提供机会，如果成功，将导致可以在神经科学和细胞生物学中广泛利用的新技术。

This award supports development of an instrument that combines near-field scanning optical microscopy (NSOM) and scanning electrochemical microscopy (SECM) with the goal of localizing specific chemicals at the surface of single neurons. Signal transmission in the central nervous system is mediated by specific chemical messengers; thus the measurement of concentration distributions of chemical species in neuronal microenvironments is critically important to improving understanding of neurotransmission and brain function. Because signaling events occur at highly localized areas whose dimensions are less than several hundred nanometers, commonly used electrochemical and optical techniques are limited by electrode size (1 micron) and by the wavelength of light. In addition, neuronal processes are highly complicated chemical events, so that simultaneous monitoring of various analytes by the combination of two or more techniques is frequently required. Synchronization of the spatial-temporal resolution of the techniques, however, is so difficult that the observed events usually lack one-to-one correspondence. The approach to be taken will overcome these difficulties through development of nanoprobes that can serve as both a light source and also an electrode. The multi-functionality allows for electrochemical and optical measurements at the same time and same location. This project explores the use of selectively etched optical fibers as a basis of electrochemical/optical nanoprobes. The etching technique allows for reproducible fabrication of optical fibers with a tip diameter of less than 10 nm. By taking advantages of the sharp fibers, electrochemical/optical nanoprobes with an active area of 100 nm in diameter will be designed and constructed. Once constructed, the tips will be tested for near-field optical imaging of single neuronal vesicles using electrochemical regulation of the probe - sample distance. The project will provide an opportunity for training of both undergraduate and graduate students in an interdisciplinary environment and, if successful, lead to new technology that can be exploited broadly in neuroscience and cell biology.