Real-Time Monitoring of Polyacrylamide Gel Electrophoresis by Schlieren Optics

Abstract
A modernized schlieren optics was applied to follow protein bands visually during polyacrylamide gel electrophoresis. A band containing as little as 0.3 μg of a protein could be detected. Besides the protein bands, usually overlooked phenomena such as boundary migration of the buffer components could be visualized. As an example, electrophoretic patterns thus obtained for SDS-polyacrylamide gel electrophoresis with a discontinuous buffer system are presented. The use of a split-type colored filter was found to be useful for coloring a particular location on the gel red or blue depending on the sign of the refractive index gradient. This means of detection also seems useful in that, firstly, it makes electrophoretic mobility measurement more quantitative and, secondly, it allows localization of a protein band and sampling in the intact state.