A simple method of drying polyacrylamide slab gels that eliminates cracking

Abstract

The polyacrylamide slab gel is the most common gel format for analyzing protein samples by electrophoresis. Drying these gels is useful in many biological applications; for example, autoradiography, in which radiolabeled proteins are separated to enable their detection and identification. Dried protein gels can also serve as an ideal method of preserving the gel itself for permanent record-keeping and allowing densitometry at a convenient time. Here I describe a simple and highly reproducible gel-drying method that results in dried gels without the cracks that are frequently encountered with many existing gel-drying methods.

Keywords: SDS-PAGE; gel cracking; gel drying; polyacrylamide gel; sieve acrylic plate.

Figure 1.. Gel-drying assembly.

(A) Schematic diagram of the gel-drying assembly. (a) Acrylic frame; (b) sieve acrylic plate; (c) clamps; (d) cellophane sheets; (e) polyacrylamide gel. A hypodermic needle is inserted at the arrow for venting air that is trapped around the edges of the gel. (B) Top view of an actual assembly containing a gel to be dried. White clamps shown in the figure can be replaced by regular binder clips. (C) Magnified view of a portion of gel-drying assembly (B) showing a hypodermic needle inserted into air pockets at the edge of gel in between the two cellophane sheets.

Figure 2.. Gel-drying device.

(A) 15 × 15 cm sieve acrylic plate with several holes of approximately 1 mm diameter each. Specially designed white clamps shown in the figure can be replaced by regular binder clips. (B) 15 × 15 cm acrylic frame with a border of approximately 1.25 cm width.

Figure 3.. Dried polyacrylamide gels.

(A) 7.5% SDS-PAGE; and (B) 4–15% gradient SDS-PAGE. These gels were air-dried using the gel-drying assembly shown in Figure 1, and as per the method described.