What is electrophoresis ?

Electrophoresis is a laboratory technique used to separate and analyze molecules, such as proteins, nucleic acids (DNA, RNA), and other charged particles, based on their size, charge, and mobility in an electric field. It is commonly employed in various fields of science, including molecular biology, biochemistry, and clinical diagnostics.

The basic principle of electrophoresis involves applying an electric field to a medium (usually a gel or a capillary) containing the sample of interest. Since many biological molecules carry a net electric charge due to the presence of positively or negatively charged groups, they will migrate in response to the electric field. The speed of migration is influenced by several factors:

Charge: Molecules with a higher net charge will migrate faster under the influence of the electric field.
Size and Shape: Smaller molecules tend to move through the medium more quickly than larger ones. Additionally, the shape of the molecules can affect their mobility.
Medium: The medium through which the molecules are migrating, such as agarose or polyacrylamide gels, can impact the separation based on size.
There are different types of electrophoresis techniques, each tailored for specific types of molecules and separation goals:

Gel Electrophoresis: In gel electrophoresis, a sample is loaded into wells within a gel matrix, and the gel is then subjected to an electric field. The two most common types are agarose gel electrophoresis, used for separating larger DNA fragments, and polyacrylamide gel electrophoresis (PAGE), which provides better resolution for smaller molecules like proteins and shorter DNA fragments.

SDS-PAGE: Sodium dodecyl sulfate polyacrylamide gel electrophoresis is a variant of PAGE used for separating proteins based on their molecular weight. SDS is used to denature proteins and give them a uniform negative charge, enabling separation based mainly on size.

Capillary Electrophoresis: This technique uses a narrow capillary tube filled with a conductive buffer, allowing for very high-resolution separations of small molecules. It is often used for analyzing DNA fragments, RNA, and small proteins.

Isoelectric Focusing (IEF): This method separates molecules based on their isoelectric point (pI), which is the pH at which a molecule carries no net charge. IEF is especially useful for separating proteins based on their charge differences.

Electrophoresis is a fundamental tool in molecular biology and biochemistry, enabling researchers to separate and study different molecules within a mixture, facilitating the understanding of their characteristics and functions.