Bio-Rad GelAir Drying System - Manual (Page 12)

2. Cut a piece of Bio-Rad filter paper (catalog number 165-0921) slightly larger than the
gel and wet it completely. Roll the gel out on top of the wetted paper. Place the paper
and gel on the bottom layer of cellophane. Using a wash bottle, add water to the surface
of the filter paper and directly around the edges of the gel. Be sure to fill in the wells of
the gels with water.
3. Cut a piece of plastic food wrap to approximately the same dimensions as the cellophane
(12.5" x 12.5"). Wet the plastic wrap in water. The wrap does not absorb water, but wet-
ting it helps make handling easier. Holding one end of the plastic wrap with both hands,
drape the other end across one edge of the plastic frame and lower the sheet to cover the
entire frame. If air bubbles are trapped beneath the plastic wrap, raise the sheet to expose
the bubbles and then lower it again. If this does not eliminate the bubbles, add more water
beneath the sheet and try again. It is important to remove all bubbles to avoid gel crack-
ing.
Fig. 11. Autoradiography gel assembly with filter paper backing.
4. Wet the second sheet of cellophane in water and lay it over the plastic wrap, ensuring all
four sides of the cellophane overhang the plastic frame. Bubbles trapped between the
plastic wrap and the top sheet of cellophane can remain. The plastic wrap may appear
wrinkled, but this is normal and should not be a concern. Continue with steps 7-9, of
Section 3.1.
5. Continue drying the gel long after it "feels" dry. If the paper is still damp (even though it
may not "feel" damp) and the gel is removed from the frame, the gel will crack. A 3 hour
drying time for a single gel on filter paper is recommended.
6. When the gel is dry, carefully peel off the cellophane top layer and plastic wrap to expose
the gel. The gel is now ready for autoradiography or fluorography.
Drying Agarose Gels
The GelAir Drying System can be used to dry agarose gels effectively and with little dis-
tortion.
1. Agarose gels require no preparation prior to drying.
2. Follow the procedure in section 3.3 (Drying Gels for Autoradiography; Cellophane
Backing. When assembling the gel sandwich, place a sheet of plastic food wrap over the
agarose gel before applying the top sheet of cellophane. The layer of plastic wrap reduces
stress on the agarose gel and minimizes cracking. Agarose gels require less effort during
assembly than do polyacrylamide gels because agarose gels do not crack when bubbles
are present around them. Lay the plastic wrap and cellophane on top of the gel and ensure
that all four sides of the plastic wrap and cellophane are overhanging the bottom frame.
Cellophane
Cellophane
Plastic Wrap
Acrylamide Gel
Filter Paper
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