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The sieving of spheres during agarose gel electrophoresis: Quantitation and modeling

1989; Wiley; Volume: 28; Issue: 8 Linguagem: Inglês

10.1002/bip.360280811

1097-0282

Gary A. Griess, Elena T. Moreno, Richard A. Easom, Philip Serwer,

Nanopore and Nanochannel Transport Studies

Abstract By use of agarose gel electrophoresis, the sieving of spherical particles in agarose gels has been quantitated and modeled for spheres with a radius ( R ) between 13.3 and 149 mm. For quantitation, the electrophoretic mobility has been determined as a function of agarose percentage ( A ). Because a previously used model of sieving [D. Rodbard and A. Chrambach (1970) Proc. Natl. Acad. Sci. USA 65 , 970–977] was found incompatible with some of these data, alternative models have been tested. By use of an underivatized agarose, two models, both based on the assumption of a single effective pore radius ( P E ) for each A , were found to yield P E values that were independent of R and that were in agreement with values of P E obtained independently ( P E = 118 nm × A −0.74 ): sieving by altered hydrodynamics in a cylindrical tube of radius, P E , and sieving by steric exclusion from a circular hole of radius, P E . The same analysis applied to a 6.5% hydroxyethylated commercial agarose yileded a steeper P E vs A plot and also agreement of the above tow models with the data. The P E vs A plot was significantly altered by both further hydroxyethylation and factors that cause variation in the electro‐osmosis found in commercial agarose.