Determination of effective hydrodynamic diameters of biopolymer molecules in high-viscosity mixtures by photon-correlation spectroscopy

Abstract

Using model high-viscosity single-component and mixed systems based on biopolymers with different molecular sizes (poly(ethylene glycol), dextran, and polysucrose) as examples, it is shown by photon-correlation spectroscopy combined with monoand polymodal analysis that solvent viscosity should be used, when calculating the hydrodynamic diameter of molecules in single-component aqueous solutions and mixed solutions of dextran and polysucrose, which have close molecule sizes, by the Stokes–Einstein equation. For mixtures of dextran and polysucrose with polyethylene glycol, the viscosity of the medium, the role of which is played by the poly(ethylene glycol) solution, should be used.