Principle and application of gel electrophoresis

2022-06-09 0 By

Electric gel electrophoresis is a technique widely used in life science laboratories to separate large molecules such as DNA, RNA and proteins.In this technique, molecules are separated according to their size and charge.Gel electrophoresis is usually performed in the laboratory to analyze DNA, RNA, or protein samples from a variety of sources.Gel electrophoresis How gel electrophoresis works Gel electrophoresis takes advantage of differences in the size and charge of different molecules in a sample.The DNA or protein sample to be separated is loaded onto a porous gel placed in an ion buffer medium.Each molecule with a different size and charge will move through the gel at a different speed when an electric charge is applied.The porous gels used in the technique act as molecular sieves to separate larger molecules from smaller ones.Smaller molecules move faster through the gel, while larger ones are left behind.The mobility of particles is also controlled by their respective electric charges.Two oppositely charged electrodes that are part of the system pull molecules towards them based on their charge.Agarose gel electrophoresis The gel used in electrophoresis is usually made from a material called agarose, which is a gel-like substance extracted from seaweed.The porous gel can be used to separate large molecules of many different sizes.The gel is immersed in a salt buffer solution in an electrophoresis chamber.Tris-borate-edta (TBE) is commonly used as a buffer.Its main function is to control the pH value of the system.There are two electrodes at each end of the chamber — one positive and one negative.Then, with the help of a pipette, the sample to be analyzed is loaded into a small hole in the gel.After loading, a current of 50 — 150 V will be applied.The charged molecules present in the sample now migrate through the gel towards the electrode.The negatively charged molecules move toward the positive pole, the positively charged molecules move toward the negative pole.The speed at which each molecule passes through the gel is called its electrophoretic mobility and is largely determined by its net charge and size.Strongly charged molecules move faster than weakly charged ones.Smaller molecules run faster, leaving larger ones behind.Therefore, strong charge and small size increase the electrophoretic mobility of molecules, while weak charge and large size decrease it.When all the molecules in the sample are of the same size, the separation will be based solely on their size.After separation, the gel is stained with dye to show the separation bands.Ethidium bromide is a common fluorescent dye used in gel electrophoresis.The gel was immersed in diluted ethidium bromide solution and placed on a UV transmittance to observe the separation band.Check or photograph the bands immediately for future reference as they spread into the gel over time.Dyes can also be pre-loaded into the gel to track the migration of molecules.Gel electrophoresis is widely used in molecular biology and biochemistry laboratories in the fields of forensic medicine, conservation biology and medicine.It is mainly applied in the following aspects:DNA analysis in isolation of DNA fragments for DNA fingerprinting to investigate crime scenes analysis of the results of POLYMERase chain reaction analysis of genes associated with specific diseases used for taxonomic studies to distinguish between different species DNA analysis in the use of DNAIn paternity identification of fingerprints in the study of protein structure and function in the analysis of antibiotic resistance for the analysis of large molecules imprinting techniques by analyzing genetic similarities between populations or species to study evolutionary relationshipsSustainable development and present situation of Biological Laboratory Consumables Tiangen Molecular biology experiment automation solution optical microscopic imaging system and sensor requirements for living cell imaging