SYBR® Safe DNA Gel Stain From Molecular Probes (Invitrogen)

Invitrogen’s SYBR® Safe DNA gel stain has completely changed the way we approach agarose gel electrophoresis in our lab. It has been able to achieve this by eliminating the use of ethidium bromide, which has been the age old benchmark for staining DNA to consequently visualize it under UV light. The SYBR® Safe DNA gel stain is one of very few products available which provide a safe alternative to traditional ethidium bromide staining.

One selling point of the SYBR® Safe DNA gel stain, which is not immediately evident from its name, is that it also works on RNA and therefore addresses all requirements for labs doing routine nucleic acid research. It is provided in solution as a concentrate in either DMSO or TBE/TAE buffers. As far as I’m aware, it can be provided diluted down to working concentrations in TBE/TAE buffers which can then be used directly to make gels, but this option is more expensive in the long term. I personally prefer the concentrate option in DMSO, which is designed to match the common working concentrations of ethidium bromide. Therefore, it can be used exactly the same way as ethidium bromide working solutions were used, either added to the pre-heated liquid gel prior to casting (in small volumes of 1 – 5 ul of the concentrate directly) or into the DNA samples at lower volumes prior to loading in the gel. I personally add 3.5 ul to 100 ml of freshly prepared agarose solution, after I’ve let it cool down to approximately 60°C. The color of the solution turns slightly redder than it would with a comparable amount of ethidium bromide. Thorough stirring of the solution ensures that the SYBR® Safe stain disperses completely and this prevents inefficient DNA staining.

Similarly to ethidium bromide, the SYBR® Safe gel stain is sensitive to light. I have compared a freshly prepared gel with a gel left overnight on the bench and observed a significant decrease in DNA visualization. This may be attributed to its long term stability in an agarose gel as well. Ever since a PhD student in our lab recommended that we use this product as a replacement to ethidium bromide from her undergraduate project experience, we have been completely converted to SYBR® Safe fans.