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Diffusion of proteins and nonionic micelles in agarose gels by holographic interferometry
Author(s) -
Kong Donna D.,
Kosar T. Fettah,
Dungan Stephanie R.,
Phillips Ronald J.
Publication year - 1997
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690430105
Subject(s) - agarose , micelle , diffusion , globular protein , chemistry , pulmonary surfactant , micellar solutions , colloid , chemical physics , chromatography , analytical chemistry (journal) , chemical engineering , thermodynamics , aqueous solution , crystallography , physics , biochemistry , engineering
Diffusion coefficients measured by holographic interferometry are presented for two globular proteins and three nonionic surfactant species in agarose gels. The cloud points for the surfactants in agarose solutions are also given. In all cases, rates of diffusion in the gel are smaller than those in bulk solution, with the hindering effect of the gel increasing both with increasing gel concentration and with increasing solute size. It is shown that the diffusion rate of the surfactant micelles is very similar to that of proteins having similar hydrodynamic radii; it would therefore appear that the size and shape of the micelles in the solution and gel phases are similar. In addition, the measured rates of hindered diffusion agree very well with rates predicted by a rigorous hydrodynamic theory in which the solutes are modeled as hard spheres and the gel fibers are modeled as straight, cylindrical fibers. Hence, for the range of conditions considered, rates of hindered diffusion for both the globular proteins and the micellar species are determined primarily by hard‐sphere hydrodynamic and steric interactions between the solute and the gel matrix.