Ethidium Bromide Alternatives?

Timothy Bushnell bushnt at
Tue May 24 01:18:50 EST 1994

In Article <2rqufh$43p at>, PHEACOCK at
(Philip Heacock) wrote:
>Hello, is there a less toxic (or safer) alternative to ethidium bromide?
>We thought of dying the DNA with ethidium homodimers (from Molecular Probes)
>but I am a little woried that this stuff is going to be a whole lot more
>mutigenic. The plus side of the homodimer is you stain the DNA before you run
>it on the gel, thus you use less than 0.1 ng per lane.  Thanks for your help.
>Phil Heacock

    I am not sure what you want.  Are you looking for a more sensitive
method for staining gels or one that is safer?  If it is the latter, we have
been using  hoechst 33258 (bisBenzimide (sigma cat. B 2883)) to stain our
gels.  This dye is not toxic but is less sensitive than ethidium bromide.  I
have been told that it binds to the phosphate backbone, but don't have a
reference for you.  You do not need to purchase a new transilluminator, but
need a different filter for a land camera (yellow I believe).

    To use this dye, make it up a 1.5x10-4M stock in water.  For a 50 ml
gel, dilue by adding 300 ul of stock to 670 ul of 1x SSC and add 700 ul to
the gel.  Add the rest to the tank buffer.  Makre sure that you then run the
gel in the dark.  Afterwords, look on a UV transilluminator and you should
see yellow-green bands.

    Again, it is not as sensitive as ethidium bromide, but a lot safer.


Timothy Bushnell
Rensselaer Polytechnic Institute
Plant Research Group

    Sigh no more ladies, sigh no more.  Men were deceivers ever.  One foot on
sea and one at shore.  To one thing constant never.  So sigh not so, but let
them go and be you bligh and bonny.  Converting all your sounds of woe into hey
nonnie nonnie.

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