Ethidium bromide (or homidium bromide, chloride salt homidium chloride) is an intercalating agent commonly used as a fluorescent tag (nucleic acid stain) in molecular biology laboratories for techniques such as agarose gel electrophoresis.

What kind of dye is ethidium bromide?

EtBr, or ethidium bromide, is also known as 3,8-diamino-5-ethyl-6-phenylphenanthridinium bromide—a dye used in biochemical research laboratories. EtBr is a red, crystalline, nonvolatile solid that is soluble in water and is available as a powder or as a solution.

What is the role of ethidium bromide?

Ethidium Bromide (EtBr) is sometimes added to running buffer during the separation of DNA fragments by agarose gel electrophoresis. It is used because upon binding of the molecule to the DNA and illumination with a UV light source, the DNA banding pattern can be visualized.