PAGE gel casting - (Aug/24/2006 )
Hi I'm pretty new to PAGE and I wanted to clarify some questions i have about polyacrylamide gel casting.
1) Is using a gel stand really necessary for casting a gel?
2) I have empty ready gel cassettes (from BioRad) and also glass plates (with spacers). Which should I use?
3) Are the gel cassettes reusable? (basically to use them after casting, I have to cut off the plastic covering at the bottom to expose the gel - can i just cover it up with parafilm or something and use it again?)
Sorry for asking such basic questions. Hope someone can answer them. Thanks!
well, we have the old fashioned plates and spacers, so i can tell you that they are good enough. i dont use the gel casting stand., i just hold the plates and spacers together with bull dog clips along the sides and seal the bottom with a thin layer of agarose. just put the clipped plates onto a clean glass surface onto which you have put a thin layer of molten agarose on -i use a pipette to make a line of agarose and press the botttom of the plates down on it. the agarose gets sucked in by capillary action to form a thin line along the base of my plates sealing it perfectly. after a cuople minutes you can cast the gel.
The way Soraya is doing is fine. however, if you need to make plenty of gels, it would be better to have the casting. You don't have time to lose with pouring gels.
I don't know how it looks, the cassettes from Bio-Rad. I have cassettes from novex (invitrogen) and I have to break them to get the gel. it's quite difficult to re-use.
If you have a casting stand, then use it. I think it's way easier to just clip the glass plates in and pour the gel as to handle with agarose and clippers. I use the stand and have no problems. Building the sandwich (glass plate, spacers, glass plate, plastic holder) and put it in the casting stand takes only 5 minutes, so no problem. It is only difficult, if your stand is old and does not fit any more tightly.
I also use only the Novex-Ready Gels from invitrogen, and these you can't reuse, only perhaps the comb. Don't know about the Bio-Rad ready gels.
We´re using the BioRad miniprotean II with 2-6 gels a day (the complete lab). With glas paltes and the spacers casting a gel needs only a few minutes in the casting stand, no need to work with agarose (i knew this technique from former times...) and the gels are pretty fine. We only use ready gels with a gradient, these are difficult to cast on your own!