Electrophoresis is a highly useful—and often-used—technique for separating proteins, RNA, and DNA, using a gel matrix through which an electric current is applied.
The gel matrix is a cross-linked polymer chosen for a specific composition and weight which depends on the type of molecule under analysis. The gel is a porous but solid matrix, which is placed into a small box. Next, samples of the material under analysis are placed into tiny wells in one end of the gel block. Once the samples have been added, an electric current is applied to the entire gel, and it is then left for several hours.
The term “electrophoresis" refers to the fact that an electromotive force propels molecules through the gel matrix. The distance that a molecule travels in the gel is dependent on its mass and charge.
When the process is complete, the gel can be stained to show the bands of protein or nucleic acid which have been separated by the electromotive force. As shown in the image provided, a single column of multiple horizontal bands represents the contents of one sample, and each band corresponds to a single DNA fragment from the initial sample.
Electrophoresis is used in a wide variety of ways, not all of which are confined to the research laboratory. The technique is used in many scientific disciplines, including biology, biochemistry, genetics, and microbiology, but is also used in forensic work, often in applications involving law enforcement.