title: Dextran permeation through poly(N-isopropylacrylamide) hydrogels.
abstract: The permeation of macromolecules such as fluoroescein-labeled dextran fractions through thermally reversible hydrogels has been investigated. A permeation model has been formulated, which takes into account hydrogel porosity and tortuosity as well as the combined effect of a geometric restraint for a relatively large solute molecule at a pore entrance and the friction between solute molecules moving through the pores and pore walls. Based on this model, we have estimated the tortuosity and average pore size of a swollen hydrogel, poly(N-isopropylacrylamide) [poly(NIPAAm)] and a swollen heterogel, poly(N-isopropylacrylamide-co-vinyl-terminated dimethylsiloxane) [poly(NIPAAm-co-VTPDMS)]. The permeation data for dextran molecules up to the size of 43.5 A in radius show good agreement with the values predicted from the model.
authors.affiliation: Alza Corp, Palo Alto, CA 94303.
authors.forename: L C
authors.initials: LC
authors.lastname: Dong
authors.forename: A S
authors.initials: AS
authors.lastname: Hoffman
authors.forename: Q
authors.initials: Q
authors.lastname: Yan
mesh_terms: D000180:Acrylic Resins; D001672:Biocompatible Materials; D002152:Calorimetry, Differential Scanning; D003911:Dextrans; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives; D007700:Kinetics; D008433:Mathematics; D008962:Models, Theoretical; D010539:Permeability; D013329:Structure-Activity Relationship
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; D003911:Dextrans; C015219:fluorescein isothiocyanate dextran; C052970:poly-N-isopropylacrylamide; D016650:Fluorescein-5-isothiocyanate