Bio-Rad PROTEAN II XL Cell - Manual (Page 19)

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4.4 Casting Agarose Gels
Agarose gels in vertical apparatus may slide down between the glass plates. To prevent this, one of the two
plates used to form the agarose gel sandwich should be a frosted inner plate (catalog number 165-1825 for
16 cm gels and catalog number 165-1826 for 20 cm gels).
1. Assemble the glass plate sandwich as outlined in Section 3, using one frosted plate and one regular clear
plate. The frosted plate should be the shorter inner plate (the plate on the inside during running). This will
allow visualization of the tracking dye during the run. Make sure that the frosted side of the plate is on the
inside of the gel sandwich.
2. Place the sandwich assembly in a warm air incubator (50 °C) for 5-10 minutes before casting the gel.
This will prevent premature gelling of the agarose.
3. Cam the warm assembly to the casting stand.
4. Immediately pour the molten (55 to 60 °C) agarose. One convenient method of pouring is to tilt the
sandwich assembly and pour agarose directly down the long rectangular glass plate.
Note: If an incubator is not available, molten (75 to 85 °C) agarose can be poured into a room
temperature sandwich assembly. This temperature is high enough to prevent premature gelling of the
agarose, yet low enough to prevent cracking of the glass plates.
5. Insert the prewarmed comb carefully.
6. Allow the agarose to cool to ambient temperature before use.