Ethidium Bromide Solution (CAS 1239-45-8)

Ethidium bromide is commonly used as a nucleic acid stain for PAGE or agarose gel electrophoresis. The fluorescence of Ethidium Bromide increases 21-fold upon binding to double-stranded RNA and 25-fold on binding double-stranded DNA so that destaining the background is not necessary with a low stain concentration (10 μg/ml). Because of the binding to DNA, Ethidium Bromide is a powerful inhibitor of DNA polymerase. Ethidium Bromide has also been used in conjunction with acridine orange to differentiate between viable, apoptotic and necrotic cells. For staining a gel after electrophoresis, dilute a sample of the stock solution to 0.5 μg/ml with water and incubate the gel for 15-30 min. Destaining is usually not needed but can be carried out in water for 15 min if decreased background is necessary. The DNA bands can then be detected on a UV light box (254 nm wavelength). Ethidium bromide can also be incorporated into the gel and running buffer at 0.5 μg/ml and visualized immediately after electrophoresis.