Amersham Biosciences Hoefer DALT, User Manual, Page: 16 / 70

Preparing the Gel Caster Hoefer DALT System
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Amersham Biosciences
Preparing the Gel Caster
Set up the gel caster near a sink, in a tray or container that can act as a catch basin for
any liquid that may overflow the unit or empty out of it when you open it to remove the
gels. Alternatively, place the unit on a plastic or rubber kitchen drain board that empties
into a sink.
The DALT Gel Caster can accommodate up to twenty-five 1-mm, or twenty-three
1.5-mm gel cassettes, with separator sheets between each cassette, before the first
cassette and after the last cassette. If you are not preparing the maximum number of
gels, use filler blocks and separator sheets to take up the excess caster volume. Place
separator sheets between the filler blocks.
Cast at least 22 cassettes for two 10-sample runs to allow for the possibility of one or
two imperfect gels.
1. Check that the caster is level. Remove the front plate and rest the caster on its back,
with its feet facing you. Place the triangular sponge in the base of the V-shaped feed
channel.
Plates are more easily loaded in this orientation. Check that the caster is clean, and
free of dust.
2. Lubricate the foam sealing gasket with a light coating of GelSeal to help assure leak-
proof sealing. Place the gasket in the groove along the front side of the caster. Avoid
stretching the gasket.
3. Start filling the gel caster by placing a separator sheet against the inside wall to
make it easier to remove the cassettes and filler blocks after polymerization.
If you are casting fewer than the maximum number of gels, first add a selection of
filler blocks, with a separator sheet between each block. For example, to cast twelve
1.0-mm gels, you may need four 25-mm blocks and one 3-mm block, with
separator sheets between each block. To cast twelve 1.5-mm gels, you may need
three 25-mm blocks, one 12-mm block, one 6-mm block, and one 3-mm block,
with separator sheets between each block.
Next add the cassettes, with all hinge strips vertical and aligned on the side of the
unit opposite the feed tube. Insert a gel separator sheet between each cassette pair.
End with a separator sheet between the final cassette and the gel caster face plate. If
necessary, use additional separator sheets to bring the level of the stack even with
the edge of the caster.
4. Put the removable front plate of the gel caster in place and screw on the black
knurled knobs. Tighten these hand tight (not over-tight), then carefully place the gel
caster in an upright position.
Be sure the sealing gasket on the front plate forms a tight seal against the face plate.