GelRed is an intercalating nucleic acid stain used in molecular genetics for agarose gel DNA electrophoresis.
GelRed structurally consists of two ethidium subunits that are bridged by a linear oxygenated spacer.
[1][2] GelRed is a fluorophore, and its optical properties are essentially identical to those of ethidium bromide.
When exposed to ultraviolet light, it fluoresces with an orange color that strongly intensifies after binding to DNA.
[3] GelRed is sold as a solution in anhydrous DMSO or ultrapurified water.