Quantitative gel electrophoresis of polystyrene particles with 20–60 nm radii on 30% crosslinked polyacrylamide gel

Abstract

AbstractThe hypothesis was tested that polyacrylamide gel which is presumably of constant fiber structure within a practical range of gel concentrations would yield a linear Ferguson plot in the gel electrophoresis of particles in the size range of 10–100 nm. Polystyrene particles ranging from 22 to 60 nm in radius were subjected to gel electrophoresis on 30% N,N′‐methylenebisacrylamide‐crosslinked polyacrylamide (2.0 to 3.2% gel concentration) containing 50 mM 3‐[(3‐cholamidopropyl)‐dimethyl ammonio]‐1‐propane sulfonate (CHAPS). Visualization of the zones required transparent gels which were formed by polymerization both at 50 °C and in the presence of 6 M urea. Ferguson plots [log(mobility) vs. gel concentration] were progressively curved with increasing particle size from 22.4 to 59.4 nm radius. As in agarose gel electrophoresis, this curvature comprises one or several sigmoidal curve elements, presumably indicative of particle compression [1, 2]. However, by contrast with agarose gel electrophoresis, the curves can be aligned along a linear, rather than a convex axis, and may therefore be designated as “overall‐linear” in essential agreement with the hypothesis underlying this study. However, contrary to expectation, the polyacrylamide gel electrophoresis of particles in the size range of interest did not provide a practical method since the gel concentration range comprising Ferguson plots of the polystyrene particles in polyacrylamide is excessively narrow and the concentration range needed for extrapolation of the Ferguson plot to obtain free mobility values is excessively wide.