Are there alternatives to ethidium bromide for staining nucleic acids within agarose gels?
There are a number of dyes that can replace ethidium bromide, but none that are both non-toxic and as sensitive. Nontoxic alternatives to ethidium bromide for staining DNA in agarose gels are basic dyes such as methylene blue, toluidine blue, azure A, and brilliant cresyl blue described by Santillan-Torres1993. For a discussion on current practices for disposal of ethidium bromide, see Hengen1994Juntibs. A more sensitive stain is SYBR Green I from Molecular Probes. This dye is extremely sensitive, but costs much more than ethidium bromide. Two forms of SYBR Green are availible. SYBR Green I is recommended for DNA and SYBR Green II is recommended for single-stranded nucleic acids (including RNA). Both can be used with a standard UV transilluminator (300 nm) but are much more sensitive when used with a 254 nm illuminator (typically an epi-illuminator). SYBR Green I from Molecular Probes can be used with either agarose or polyacrylamide gels, and is particularly suitable for low amount of
