GelRed

GelRed is an intercalating nucleic acid stain used in molecular biology for agarose gel electrophoresis. GelRed is structurally closely related to ethidium bromide and consists of two ethidium subunits that are bridged by a linear spacer.

Its fluorophore, and therefore its optical properties, are essentially identical to those of ethidium bromide. When exposed to ultraviolet light, it will fluoresce with an orange color that strongly intensifies after binding to DNA. The substance is marketed as a less toxic and more sensitive alternative to ethidium bromide. GelRed is sold as a solution in DMSO or, more recently, in water.