Characteristics, types, preparation methods and product introduction of microelectrode

1.  characteristics of microelectrode

The common electrode size in electrochemical research is millimeter level, which limits its application in some fields due to its relatively large size. A microelectrode is an electrode less than 25 μm on at least one dimensional scale, whose size is smaller than the diffusion layer thickness. Compared with traditional electrodes, microelectrodes have many advantages, such as small size, high current density, fast response, low IR drop and high reliability

High noise ratio, fast mass transfer speed, easy to reach steady state, etc. These characteristics of microelectrodes can achieve fast and high sensitivity detection.

There are a variety of methods for the preparation of microelectrodes, including electrodeposition, electrochemical etching, laser drawing and internal filling, as well as self-assembly technology, chemical vapor deposition, template method, ion beam etching technology, screen printing, ultraviolet illumination

New methods such as radio-chemical coating technology. Microelectrodes are widely used in cell detection and in situ analysis of living organisms in the field of life analysis. After modification on the surface of the microelectrode, it can be used to achieve highly selective and sensitive detection of the content of neurotransmitters in cells and in vivo, as well as some key signal molecules of NO and CO in vivo. Microelectrodes can be widely used in the field of in vivo analysis, biosensing, biological cell detection, scanning probe microscopy, capillary electrophoresis ⁃ electrochemical detection system, life science, food science and environmental analysis and monitoring and other fields, for the development of chemical sensors, biosensors for fast, high sensitivity detection.

2. Type and preparation method of microelectrode

According to different electrode materials, microelectrodes are mainly divided into non-metallic microelectrodes and precious metal microelectrodes. Carbon microelectrode, carbon fiber microelectrode and carbon nanotube functional microelectrode are the main non-metallic microelectrodes, and platinum microelectrode and gold microelectrode are widely used in precious metal microelectrodes. According to the shape characteristics of microelectrode, microelectrode can be divided into micro-disk electrode, micro-disk electrode, micro-ring electrode, micro-array electrode and so on. Screen printed electrode and thin film microelectrode are two kinds of microelectrodes which are widely used at present.

The traditional methods of preparing microelectrodes are mainly electrodeposition and electrochemical etching, self-assembly technology, ion beam etching technology, screen printing technology, chemical coating technology and so on. Among them, electrochemical etching method has low cost, simple instrument and good reproducibility, and smaller microelectrodes can be obtained after several times of insulation, but the preparation process is more complicated, and electrochemical etching method mainly prepares hemispherical microelectrodes. The microelectrodes prepared by various methods include carbon ultramicroelectrode, carbon nanotube microelectrode, carbon fiber microelectrode, platinum microelectrode, and gold microelectrode, which are used for single cell detection, in vivo analysis, detection of biochemical substances such as dopamine and glucose, and detection of small molecule substances such as oxygen and superoxide ions.

3, microelectrode products and applications

There are many kinds of microelectrodes, and different products developed by different manufacturers are also different. Several commonly used microelectrode products are introduced.

Spain Micrux uses lithography technology, as well as metal deposition and stripping process to prepare thin film metal microelectrode, electrode material is platinum or gold, metal microelectrode size of 10x6x0.75mm, small size, high detection sensitivity, low reagent consumption and low cost efficiency, suitable for 1-5ul sample detection. There are many types of thin film metal microelectrodes, including metal single electrode, metal micromulti-electrode, microarray electrode, fork value microelectrode, fork value microarray electrode, annular fork value array electrode, and microfluidic microelectrode developed in combination with microfluidic microelectrode, etc., and provide a multi-functional working platform suitable for microelectrodes, droplet and flow state detection. Suitable for the development of biosensors and flow state detection.