Trans-Blot® SD Semi-Dry Electrophoretic Transfer Cell From Bio-Rad

Trans-Blot® SD Semi-Dry Electrophoretic Transfer Cell From Bio-Rad
The Bio-Rad Trans-Blot® SD Semi-Dry Electrophoretic Transfer Cell allows for efficient blotting of proteins from polyacrylamide gels onto PVDF or nylon membranes in only minutes. The system accomplishes this by producing high field strength (V/cm2). It can also be used to blot DNA: ranging from several hundred bases to 15 kb, or RNA: up to 3.5 kb, from agarose gels onto nylon membranes, without any gel pretreatments. In our lab, however, we use this system exclusively for transferring proteins onto membranes for subsequent Western blot analysis. The Bio-Rad transfer cell is very compact, measuring 16 x 21 cm. It can transfer a maximum gel size of 15 x 20 cm. I have transferred up to 3 mini acrylamide gels with this unit without compromising transfer efficiency.

After running my acrylamide gels, I transfer my proteins to a PVDF membrane in order to perform Westerns with antibodies of interest, usually anti-HSF-1 or anti-actin. I typically incubate the gel in transfer buffer for about 10 minutes before transferring to the membrane. After activation in methanol, I also incubate the PVDF membrane in transfer buffer. For some unknown reason, I get a more efficient transfer by incubating the gel and membrane in transfer buffer before doing the actual transfer. Next, I cut out four pieces of Bio-Rad extra thick blotting paper so that they are a little bigger than the gel and PVDF membrane. I wet two of these pieces of blotting paper and place them on the platinum anode. I drain off extra buffer and remove bubbles that may be trapped by rolling over the paper with a glass pipette. Next, I carefully place the PVDF membrane on top of the blotting paper and then place the gel on top of the PVDF membrane. The sandwich assembly is completed by placing another two thick, pre-wetted pieces of blotting paper on top of the gel. To remove any remaining trapped bubbles and excess buffer, I roll the glass pipette over the whole sandwich a couple of the times. I then add few drops of buffer at the top to resaturate the sandwich. Next, the cathode is placed on top and locked into place. The position is well-marked to prevent the electrode being placed in the wrong direction. Finally, the safety cover is placed onto the unit and plugged into our Bio-Rad power supply. In our situation, we find that we get optimal transfer of proteins to the membrane when the transfer is run at 15 volts for 30 minutes. I have tried using higher voltage for shorter period of time, but the transfer efficiency is reduced.

This system requires very little maintenance. It just needs to be wiped off with 70% ethanol. The unit is very durable; we haven’t had any problems with this unit.

Hee Chul Lee
Research Fellow
University of Michigan
Internal Medicine

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Trans-Blot® SD Semi-Dry Electrophoretic Transfer Cell From Bio-Rad
The Good

It is a lot quicker than using a fully wet transfer.

The Bad

Even with all the pipette-rolling, I still seem to get few bubbles as seen on my Westerns. In the beginning, needed to work out the parameters for optimal transfer.

The Bottom Line

It beats waiting an hour to transfer as with a traditional, wet system which also requires a lot of transfer buffer. Great product.