Two-dimensional electrophoresis separates the same sample with two distinct separation techniques or two different electrophoresis separations. The separated bands from one electrophoresis are resolved more with the second electrophoresis.
IEF, followed by PAGE or AGE, is the most frequent two-dimensional electrophoresis. The gel from the IEF capillary is removed and placed across the PAGE or AGE gel slab at right angles for the second electrophoresis. If PAGE is used for the second electrophoresis, it is often PAGE with SDS.
Two-dimensional electrophoresis can also be a single sample run on either agarose or polyacrylamide gels. The gel is then turned 90 degrees, and the same electrophoresis is run on the separated solutes to separate each band from the first run into more bands.
The image shows a two-dimensional electrophoresis separation of proteins, which is IEF followed by PAGE with SDS. IEF first separated the proteins on a very narrow gel strip. This strip was then positioned at the top of a polyacrylamide gel with SDS for the second electrophoresis. The IEF gel has a very narrow strip on top, and the remainder of the image shows the many separated proteins on the PAGE with SDS.
