Ethidium bromide thanks to its ability to show an intense fluorescence (ex 300nm/em 620nm) after binding with DNA.
Ethidium
bromide (EB) is inexpensive, sufficiently sensitive and very stable and thanks
to this property has been the stain of choice for nucleic acid gel staining for
decades.
However on the other hands, EB is also a known powerful mutagen.
Recent years
alternative reagents able to show an intense fluorescence
after binding with DNA but not able to permeate cell membrane were developed:
My preferred one:
Gel REd - Biotium (VWR cod. 41003)
https://biotium.com/product/gelred-nucleic-acid-gel-stain/
Safety assessment available at:
https://biotium.com/wp-content/uploads/2013/07/GelRed-and-GelGreen-Safety-Report.pdf
Cost: About 90€
for 500ul (stock 10000X) à 90€ for 5liter of agarose à 0,9€ for a mini gel
(15x2well)
2,5€ for a midi gel (up to 30x2 well)
Another
alternative that I used in the past is the Sybr Safe (thermo cod. S33102)
is another
possible alternative. but in my experience, it shows limited stable under UV
excitation.
More details are
available in the following link
