Sensing technology is the frontier technology of modern science and technology, is one of the popular fields of people's research, occupies an extremely important position in the construction of the national economy, and the level of sensing technology is one of the important indicators to measure the level of scientific and technological development of a country. The development of new biochemical sensors with high sensitivity, high selectivity, fast response, good reproducibility and wide application is of great significance in the fields of pharmaceutical analysis, disease diagnosis, food hygiene and environmental monitoring.
Biochemical sensors refer to a type of sensors that are sensitive to biochemical materials and can convert the biological or chemical reactions produced by the substances to be detected into corresponding optical signals, electrical signals, thermal signals, etc., which can be identified. Biochemical sensors generally consist of three parts: an identification element, a converter, and a signal amplification device [1]. Its working principle is shown in Figure 1, when sensitive elements (antigens, antibodies, nucleic acids, sugars, lipids, proteins, tissues, cells, microorganisms and other bioactives) combine or interact with the target molecule, its physical and chemical properties and parameters will change accordingly, such as changes in light intensity, color, mass, charge, resonance frequency, etc., and then converted into electrical signals or optical signals through signal converters, after amplification and processing, and finally the signal will be displayed in the form of appropriate visualization. So as to achieve the purpose of analysis and detection.
Fig.1 Schematic diagram of the composition and principle of the biochemical sensor.
In 1962, the first biochemical sensors were developed to detect glucose in the blood [2], and since then a large number of different types of biochemical sensors have been developed, but only a few of them can meet the requirements of high reliability for commercial applications. In recent years, the advent of micro-electro-mechanical systems (MEMS) technology has brought about a turning point in the development of biochemical sensors [3]. MEMS is a cutting-edge high-tech technology developed on the basis of microelectronic technology, which has been widely used in agriculture, biology, medicine, information, automatic control, aerospace, military and other fields by combining electronic functions with mechanical, optical or other functions [4]. Compared with the traditional electromechanical system technology, MEMS has the following characteristics [5]:
1.Miniaturization: MEMS devices are small in size, light in weight, large in specific surface area, low in energy consumption, small in inertia, low in cost, and can be mass-produced.
2.Integration: Multiple sensors with different functions and sensitivities can be integrated into one to form a microsensor sequence or microactuator array to complete a specific function, and devices with different functions can be integrated together to form a powerful microsystem.
3.With silicon as the main material, excellent mechanical and electrical properties: silicon has the advantages of strength, hardness, light weight and good thermal conductivity.
References: 1] Xu Kejun, Ma Xiushui, Li Xiaolin. Sensors and Detection Technology[M].Beijing: Publishing House of Electronics Industry, 2008
2] clark l c jr, lyons c, electrode systems for continuous monitoring in cardiovascular surgery[j]. ann ny acad sci, 1962,102:29-45.
3] Guangyu Liu, Shangchun Fan, Haomin Zhou, Micromechanical and electronic systems and their applications[M].Beijing: Beihang University Press, 2003
4] Dong Zhang, Reflections on the development trend and challenges of MEMS[J].Science and Technology Information Development and Economy, 2006, 24: 180-181
5] Ma Qiang, Li Wenshi, Zhu Zhen, Research status and progress of MEMS[J].China Integrated Circuit, 2004, 10: 57-61+21
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