Stained Gels Can Be Stored for Several Months in Nonsealed Polyethylene Bags

It is customary to dry gels (SDS-PAGE, native gels, or two-dimensional gels) after staining for record keeping purposes. This is typically carried out with gel dryers or by drying between two cellophane sheets held together by acrylic frames. Here, we report a simple method to store a variety of stained gels without any storage buffer within flexible nonsealed polyethylene bags. Gels can be stored for several months at room temperature without significant shrinking or protein diffusion. The gel stays hydrated owing to the de facto sealing achieved by the polyethylene sheets adhering air-tightly to the gel on either side. The microsaturated environment generated by the thin film of water molecules trapped between the gel and the polyethylene sheets, combined with the nonporous nature of the polyethylene sheets, apparently keeps the gel from cracking or shrinking significantly. The intensity of stained proteins increased during storage probably from the slight gel shrinkage observed. Storing gels in this manner is convenient (a) when low abundance protein spots from multiple two-dimensional electrophoresis gels have to be excised for in-gel tryptic digestion or electroelution and (b) for wet gel autoradiography. In addition to avoiding dryer contamination and saving drying time, these bags prevent the moist gel from sticking to X-ray film. Such storage could also prove useful for electrophoretic transfer of fixed and stained gels.