I have been using TBE-PAGE gel to see small fragments of DNA by post-staining that means gel is stained with EtBr after electrophoresis. Someone told me that you can add EtBr before polymerizing acrylamide, but I have never seen protocols like that.

Have you added EtBr before polymerization? Have you compare these staining methods? Let me know your experiences and knowledge.

  • 1
    $\begingroup$ TBE-PAGE gels generally take a while to run (especially the big Urea-PAGE gels for RNA) and the EtBr can quickly migrate out of the gel. Since PAGE gels are relatively thinner than agarose gels, staining post-run is not a problem. However, I have not really tried adding EtBr before polymerization. $\endgroup$
    Commented Aug 31, 2015 at 5:14
  • $\begingroup$ You can also add some EtBr to the running buffer in the anode chamber. The EtBr is positively charged and will migrate through the gel towards the cathode while the nucleic acids in your sample will migrate towards the anode. $\endgroup$
    – mdperry
    Commented Sep 1, 2015 at 23:09
  • $\begingroup$ Thank you for the comments, all. I seems you can add EtBr in gel before polymerization. And I could see the problem when doing so, and the solution. $\endgroup$
    – 243
    Commented Sep 2, 2015 at 16:58


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