Partition and Permeation of Dextran in Polyacrylamide Gel

Abstract

Partition of sized FITC-dextrans in polyacrylamide gel showed a relationship between Kav and solute radius as predicted by the theory of Ogston, which is based solely on geometry of the spaces. Permeability data for the same dextrans were fit to several theories, including those based on geometry and those based on hydrodynamic interactions, and the gel structure predicted by the partition and permeability data were compared. The Brinkman effective-medium model (based on hydrodynamic interactions and requiring a measure of the hydraulic conductivity of the matrix) gave the best fit of permeability data with the values for fiber radius (rf) and void volume of the gel (epsilon) that were obtained from the partition data. The models based on geometry and the hydrodynamic screening model of Cukier, using the rf and epsilon from partition data, all predicted higher rates of permeation than observed experimentally, while the effective-medium model with added term for steric interaction predicted lower permeation than that observed. The size of cylindrical pores appropriate for the partition data predicted higher rates of permeation than observed. These relative results were unaffected by the method of estimating void volume of the gel. In sum, it appears that one can use data on partition of solute, combined with measurement of hydraulic conductivity, to predict solute permeation in polyacrylamide gel.

Obesity as a predictor of adverse outcome across black and white race

“…It is a biocompatible polymer easily moldable with UV light and characterized by a non‐adhesive surface, which allows the formation of EBs, and it is selectively permeant to soluble molecules of defined dimensions. It is evident that the larger the molecule then the lower the permeability of the PA hydrogel to this molecule (Williams et al, 1998). This property of the biomaterial permits the accumulation of molecules with molecular weights higher than the polymer cutoff.…”

Macroporous Poly(N‐isopropylacrylamide) Hydrogels with Adjustable Size “Cut‐off” for the Efficient and Reversible Immobilization of Biomacromolecules

“…However, it is much more probable that similar to results for other gels, e.g. crosslinked polyacrylamide, [33] the partitioning and permeation of linear dextrans into the crosslinked PNIPA can not be appropriately described with the Stokes radius while this is possible for globular proteins. Hence, the Stokes radii also over-estimate the hindrance for the uptake of dextran in the temperature-responsive gels.…”

Hydrodynamic radius ladders of proteins

“…One approach has been to use a series of proteins that differ in molecular weight; these proteins also differ in surface properties (e.g., charge and hydrophobicity) that can affect transport [1,2]. Another approach uses fractions of Dextran and other linear polymers of different average molecular weights [3]; these fractions are polydisperse in size and have conformational properties dissimilar to folded proteins (i.e., random coil vs. compact conformations) that result in distinctive hydrodynamic properties [4].…”