Development of High-Resolution Scanning Electrochemical Microscopy for Nanoscale Topography and Electrochemical Simultaneous Imaging

Abstract

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 probesample 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.

Evaluation of Redox Activity of Human Myocardium‐derived Mesenchymal Stem Cells by Scanning Electrochemical Microscopy

“…The experiments were carried out in the following order: the UME was set to a negative potential and brought as close as possible to the cell's bottom surface. Afterwards, the electrochemical cell/bath was switched off immediately (voltage switching mode) . After adding a known amount of redox mediator, the media was mixed gently, a positive potential was applied and the UME was retreated at 200 μm from the cell's surface.…”

Biological imaging with scanning electrochemical microscopy

“…Though, currently, shear force-based feedback is the leading methodology for constant-distance SECM work on cells, the specific positioning task has also been accomplished with alternative distancedependent signal inputs for the regulating control units. Examples include responsive circuitries using DC [46,47] and AC [48] SECM tip currents or probe impedance [46]. Problematic for all currently available solutions for constant-distance cellular SECM is the technical complexity of the necessary apparatus, the need for high user skills for successful operation and the relatively long duration for the completion of full living cell scans.…”

Nano- and Microsensors for In Vivo Real-Time Electrochemical Analysis: Present and Future Perspectives

“…Nanopipettes offer several important advantages, including ease of manufacture, small size, and needle-like geometry. This makes them a suitable probe for scanning probe microscopy, including in scanning ion conduction microscopy (SICM) [ 41 , 42 , 43 ] and scanning electrochemical microscopy (SECM) [ 44 , 45 ].…”