| Name | Electrophoresis |
| Synonyms | Electrophoresis |
overview
Electrophoresis (Electrophoresis ), the phenomenon of charged particles moving in a fluid under the action of electric field force. The method of separating, identifying or preparing amino acids, proteins, nucleic acids, inorganic ions, virus particles and living cells by applying this phenomenon is called electrophoresis technology. Electrophoresis technology is widely used in biochemical industry, clinical medical examination, molecular biology, agricultural breeding and crop, livestock and poultry metabolism research.
introduction
In 1807, Russian physicist F.F.Reuss observed electrophoresis. In 1897, F.Kochlausch derived the theoretical formula for ion movement in an electric field. Early researchers used cation electrophoresis to represent the movement of charged colloidal particles. The movement of small molecules in the electric field is represented by ion electrophoresis. In 1909, L. Michae-lis used English for electrophoresis (Electrophoresis) for the first time. In 1937, Tiselius (A.Tiselius) established mobile interface electrophoresis and successfully divided serum protein into 5 main components. He won the 1948 Nobel Prize in Chemistry. After the 2050s, paper electrophoresis and polyacrylamide gel electrophoresis were commonly used in biological research. The immunoelectrophoresis established by the combination of electrophoresis technology and immune technology has greatly promoted the development of immunology. Isoelectric point focusing technology greatly improves the resolution of electrophoresis. Two-dimensional electrophoresis technology was established in the 70 s to bring molecular biology research to the level of a single subunit. In the 1980s, the alternating pulsed electric field gradient gel electrophoresis technology was invented to better separate the chromosomal DNA molecules of eukaryotic cells.
principle
The particles in the solution become charged particles due to their own ionization or adsorption of certain ions in the liquid, or the liquid molecules adsorbed on the surface of the particles are ionized. Due to the different charging properties of different substances, the direction and speed of movement in the electric field are also different. Electrophoretic mobility (also known as swimming mobility) is commonly used to indicate the swimming speed of charged particles with different characteristics in the same electric field. Electrophoretic mobility refers to the swimming velocity of charged particles under unit electric field intensity. The mobility is determined by the net charge, size and shape of the particle, as well as the liquid resistance of the particle during swimming, the degree of hydration and dissociation trend of the particle.
influencing factors
particle swimming speed is not only affected by its own properties, but also affected by other external factors. The main ones are: ①The higher the electric field strength, the faster the charged particles move; ②The farther the pH value of the solution is from the pH value of the particle isoelectric point, the more net charge the particle carries, and the faster the swimming speed; ③The ionic strength of the solution The higher the particle swimming speed, the slower the particle swimming speed, the more heat generated by electrophoresis, and the faster the temperature of the electrophoresis system; ④The increase in temperature increases. In addition, the dielectric and chemical properties of the solution, the amount of viscosity and polar molecules, as well as the adsorption and heterogeneity of the support, ion exchange capacity, electroosmosis, siphon, evaporation, etc. will affect the electrophoresis process.
device
It consists of power supply, electrophoresis tank and auxiliary equipment for temperature and humidity control. The power supply is a high-power rectifier device with stable voltage or current performance. The voltage can reach 5,000V and the current can reach 400 mA. There are various forms of electrophoresis tanks, including tubular, horizontal, vertical, etc. Both ends of the electrophoresis tank are buffer storage tanks, and platinum wire electrodes are connected to the power supply.
Electrophoresis technology has simple equipment, convenient operation, high resolution and good reproducibility. The results of electrophoresis can be displayed or measured by dye staining, ultraviolet absorption, autoradiography, biological activity of enzymes, laser scanning and other methods.
application
Electrophoresis technology is widely used in various theories and application branches of biology. In clinical medicine, electrophoresis technology is the first to show that albumin and multiple globulin particles contain several components, and it is used in liver cirrhosis, Diagnosis of jaundice, bone marrow cancer, etc.; in agriculture, isoenzyme technology is often used to electrophoresis proteins in crop seeds or animal and plant tissues, and then enzyme color technology is used for zymogram analysis, comparison of variety differences and metabolic characteristics. Agarose gel electrophoresis is often used in the purification and analysis of nucleic acids in the breeding process. Electrophoresis technology is indispensable for molecular biology research. The purification and molecular weight determination of biological macromolecules, the study of gene expression products, the detection of plasmids and gene recombinants all require electrophoresis technology. F.Sanger of the United Kingdom and Gilbert of the United States (W.Gilbert) used electrophoresis to establish a rapid DNA sequence analysis method and P.Berg of the United States to share the 1980 Nobel Prize in Chemistry. In recent years, electrophoresis technology has been used to separate and purify bioactive substances in the test module of the Columbia Space Shuttle in the United States. For the first time, electrophoresis technology has been studied under weightlessness.
References
[1] China Agricultural Encyclopedia Editor-in-Chief Committee Biology Volume Editorial Committee, China Agricultural Encyclopedia Editorial Department. China Agricultural Encyclopedia. Electrophoresis.
[2] China Agricultural Encyclopedia Editor-in-Chief Committee Soil Volume Editorial Committee, China Agricultural Encyclopedia Editorial Department. China Agricultural China Agricultural Encyclopedia.