Development of high-resolution scanning electrochemical microscopy for nanoscale topography and electrochemical simultaneous imaging

This article reviews our recent progress in the development of high-resolution scanning electrochemical microscopy (SECM) and its application to biological samples. SECM uses an ultramicroelectrode (UME) as a probe and a scanning mechanical stage for controlling the probe position. To improve the resolution of SECM, we have developed a fabrication method for pyrolytic carbon nanoelectrodes and a current feedback system for probe-sample distance control. The current feedback system effectively provides high-quality electrochemical and noncontact topography images because the current signal depends on the probe-sample distance. High-resolution SECM has overcome the limit of microscale imaging resolution and enabled the imaging of local regions within cells. In this study, we address four topics: nanoelectrode fabrication, current feedback probe-sample distance control systems, membrane protein imaging, and neurotransmitter detection.