Previously, I have used the Bio-Rad mini-vertical gel electrophoresis unit. Here, I am in a new laboratory which uses the Hoefer SE 245 Dual Gel Caster. Frankly, I am very impressed with this unit, which has some unique modifications as compared to other units, especially when it comes to alleviating the problem of leakage. I am sure many people have encountered leakage problems when pouring their polyacrylamide solution into a gel caster, especially at the bottom of the assembly or when the plate separators on the side are shifted slightly inward. Well, the SE 245 Dual Gel Caster does a wonderful job in fixing these problems with some novel, simple modifications.
The SE 245 Dual Gel Caster, as the name implies, can make one or two glass plate sandwiches for pouring one or two mini polyacrylamide gels. Different size spacers can be purchased, which accommodate different comb sizes. We use primarily the 0.75 mm and the 1.0 mm size combs. As a side note, even with the 1.0 mm combs, I can only load 25 ul per lane, at best. A cam (a plastic knob which is inserted and rotated, pushing the gel sandwich downwards against the silicone rubber casket to create a very tight seal) on each side of the casting cradle seals the bottom of the sandwich against a silicone rubber gasket. The casting cradle can fit two casting clamps, each with its own gel sandwich. The casting clamp, with the pressure bar and three clamp screws on each side, holds the glass plates tightly, with the spacers in between. The T-shaped spacers, a great modification in my opinion, ensure that the spacers do not accidentally move inward, which can cause leakage. The long flat side of the T-shaped spacers fits between both plates, and the top of the T rests along the sides of the plates. The glass plate sandwich slides into the casting clamp and is secured by tightening the six screws. Then, the casting clamp is placed on the casting cradle and fastened with the cams which are inserted on each side and turned, sealing the sandwich tightly to the rubber casket. As you can see, there are many layers built in to ensure that leakage does not occur, without compromising on time and space.
The gel is poured between the glass plates. Once the gel is polymerized, the whole thing is disassembled, and the gel sandwich is removed from the casting clamp. The only negative of this product is that a few times while trying to remove the gel sandwich from the casting clamp, which can get stuck to one side of the clamp even with the screws loosened, the glass plates holding the gel separated, introducing air pockets and making the gel totally useless.
Besides washing the components and getting rid of the residual polymerized gel after use, there is very little maintenance involved. The components are sturdy and very well made.
Hee Chul Lee
University of Michigan