Although most labs have optimized protocols for pouring gels prior to Western and immunoblot analysis, these experiments are often associated with variability and can be difficult for novices to master. Many different systems are available for pouring gels, in addition to the options of pre-cast gels. Most of these systems are not interchangeable, thus a lot of money can be spent on various systems before identifying which is the preferred platform. Therefore, some important things to research before purchasing a polyacrylamide system are ease of use, reliability and durability.
BioRad offers a complete kit for pouring and running gels. The system includes a gel casting stand and plates, a cell that can run one or two gels and a minitank that can be interchanged with other BioRad electrode modules for blotting, electrophoresis, and electro-elution. The plates that come with the system have permanently bonded spacers, which help with putting the system together, as well as, preventing leaking during the casting process. I have used this system for over 4 years and have found these spacers to be convenient and durable. They make putting together the apparatus and cleaning it much easier than dealing with separate spacers. One downfall to this is that you have to purchase additional plates to alter gel thickness, but the plates seem to be much more durable than traditional thin glass plates.
Although the BioRad system seems to be quite durable, unfortunately, the casting stand leaks easily during polymerization once the springs stretch out, a frustration that can result in loss of valuable time. I have found that placing parafilm on the bottom of your plates to act as a second seal before placing them on the casting stand prevents leakage and frustration. This helps with older systems that leak and can be beneficial with new systems because it serves as a backup to prevent potential leaks that can ruin a day of work. If you prefer to not pour your own gels, this system is still a good option because the running cell (and other accessories sold separately) fit the pre-cast BioRad gels, as well.
Another problem with this system is that the gel running cell can leak buffer if it is not positioned correctly against the plates. With a little practice in putting the system together this type of leak can be avoided, but if you are new to this system, it is best to check for leaks before you start running your gels. Otherwise, you will find yourself stopping your gel mid-run in order to fix the problem. All in all, this system does have problems (specifically, the leaking gel caster and gel running cell), however, with the tips I have mentioned above the problems can be avoided making this system worth the price for most labs.
Amy Bellmeyer, M.S.
Research Technician
Division of Pulmonary and Critical Care Medicine
Northwestern University