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Apparent persistence lengths and diffusion behavior of high molecular weight hyaluronate
Author(s) -
Ghosh Snehasish,
Li Xiao,
Reed Christopher E.,
Reed Wayne F.
Publication year - 1990
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360301110
Subject(s) - chemistry , ionic strength , persistence length , diffusion , dilution , radius of gyration , thermodynamics , analytical chemistry (journal) , electrolyte , polymer , chromatography , aqueous solution , organic chemistry , physics , electrode
High purity, high molecular weight hyaluronate from bacteria and rooster comb exhibited clear polyelectrolyte properties, as observed by static and dynamic light scattering. The scattered intensity of hyaluronate solutions increased markedly with ionic strength, while the radii of gyration decreased. Apparent persistence lengths within the wormlike chain model in the coil limit were estimated as a function of ionic strength. The total apparent persistence length varied from about 87 Å in the high ionic strength limit to nearly 400 Å at 1 m M added NaCl. The apparent electrostatic persistence length varied approximately as the inverse square root of the ionic strength. Deviations from the theoretically predicted inverse ionic strength dependence were investigated in terms of excluded volume effects. Dynamic light scattering yielded “ordinary phase” diffusion coefficients whose dependence on polymer and salt concentration agreed reasonably well with hydrodynamic coupled mode theory in the linear limit. Extrapolations to infinite polymer dilution at fixed salts yielded, surprisingly, a constant diffusion coefficient. Thus, there was no evidence of either polyion expansion or electrolyte friction effects in the infinite dilution diffusion coefficients. Since clear evidence for polyion expansion was seen in the static scattering, it is thought that the relative stiffness and consequent openness of the hyaluronate coils lead to partial free draining behavior. There was no evidence for an “extraordinary phase” under no added salt and low added salt conditions. The overall results are contrasted with the very different behavior previously reported for medium purity hyaluronate from animal sources.