title: Polyelectrolyte complexes and layer-by-layer capsules from chitosan/chitosan sulfate.
abstract: Polyelectrolyte complex formation of chitosans of varying average molecular weight and degree of acetylation with chitosan sulfate or poly(styrene sulfonate) was studied by static light scattering in dilute solution at various ionic strengths. Unlike the molecular weight, the degree of acetylation was found to have a significant effect on the resultant structural densities of the complexes. The same system was applied to the preparation of micrometer-sized hollow shells by means of a layer-by-layer technique (in total eight layers). Their behavior toward fluorescent probes such as fluorescein and rhodamin 6G or fluorescein isothiocyanate labeled dextrans at various ionic strengths and pH (observed by confocal laser light scanning microscopy) could be understood through a discussion of electrostatic forces between the highly charged shells and the probes to be dominant. At an ionic strength of 0.1 M and above, charge effects are largely suppressed (screening effect) and a size-dependent "cutoff" for the permeation of the macromolecular fluorophore was observed.
authors: Max Planck Institute for Colloids & Interface Research Golm, D-14424 Potsdam, Germany. Gisela.Berth@Capsulution.com
authors: Gisela
authors: G
authors: Berth
authors: Andreas
authors: A
authors: Voigt
authors: Herbert
authors: H
authors: Dautzenberg
authors: Edwin
authors: E
authors: Donath
authors: Helmuth
authors: H
authors: Möhwald
mesh_terms: D000107:Acetylation; D002214:Capsules / Q000737:chemistry*; D002686:Chitin / Q000031:analogs & derivatives* / Q000737:chemistry*; D048271:Chitosan; D018625:Microscopy, Atomic Force; D008970:Molecular Weight; D009994:Osmolar Concentration; D010539:Permeability; D000071228:Polyelectrolytes; D011108:Polymers / Q000737:chemistry*; D011137:Polystyrenes; D013431:Sulfates / Q000737:chemistry
chemical_list: D002214:Capsules; D002686:Chitin; D048271:Chitosan; D000071228:Polyelectrolytes; D011108:Polymers; D011137:Polystyrenes; D013431:Sulfates; C003321:polystyrene sulfonic acid