Gel electrophoresis is a mainstay of molecular biology. So obviously making it cheaper will benefit both research labs and DIY biologists alike. While perusing blogs and other websites I collected a number of projects and instructions that ought to help make one a cheapass.
Sodium boric acid buffer (cheaper faster gels)
The running buffers TAE (TRIS acetate EDTA) and TBE (TRIS borate EDTA) are two of the most common types of electrophoresis buffers. According to a paper by Jonathan Brody and Scott Kern (link below), a sodium borate (SB) buffer is a better choice than either TAE and TBE. At normal electrophoresis voltages their results suggest the 3 buffers (TAE, TBE, SB) are roughly equivalent, with a potential edge given to SB buffer. However, in the high voltage contest (300V+ ish) SB is the better choice (TBE and TAE melt at high voltages).
The SB buffer utterly dominates TBE and TAE for reasons I will explain. SB buffer is cheaper per gel than the other two – TAE=$0.27, TBE=$0.67, SB=$0.07 (data from the Bordy et. al. paper). The results quality of a gel in SB buffer at normal voltages and high voltages is as good as the other two buffers at normal voltages. A higher voltage leads to faster migration time and the paper and comments on the paper suggest a 60 minute run in TAE or TBE can be completed in 20 minutes with SB buffer.
I tried to make some SB myself but had some issues, I think, because I lacked boric acid (to to adjust the pH). I tried making the SB buffer with sodium tetraborate and 1N HCl but the gel melted at 300V and 150V. I suspect part of the issue is the chloride ions from the HCl and the other part is the power-supply. I am using a 75W max unit and repeatedly the machine hit max power and the voltage couldn’t be maintained. Once the boric acid arrives I’ll be trying the experiment again.
Recipe (from Brody’s paper)
- 1X Stock
- 5mM sodium tetraborate decahydrate (disodium borate decahydrate) adjusted to pH 8.5 with boric acid.
- 20X stock
- 100mM sodium tetraborate decahydrate (disodium borate decahydrate) adjusted to pH 8.0 with boric acid (when the stock is diluted to 1x the pH will be correct)
Sodium boric acid: a Tris-free, cooler conductive medium for DNA electrophoresis (PDF, Minnesota State University)
DIY Hardware Guides
I am less familiar with the hardware side of electrophoresis so I will simply link any readers over to the following projects. When I get the time to build one I will share my experience.
Build a gel box – University of Utah’s Instructions (PDF)