title: Macro-hydrogels versus nanoparticles by the controlled assembly of polysaccharides.
abstract: The controlled assembly of oppositely charged chitosan (CS, Mw ∼ 33 × 10(3) to 600 × 10(3)g mol(-1)) and dextran sulfate (DS, Mw = 1.3 × 10(6)g mol(-1)) or heparin (HP, Mw = 1.8 × 10(4)g mol(-1)) led either to nanoparticles or macro-hydrogels, at room temperature. The control over the electrostatic attractive interactions was achieved using 2 mol L(-1) NaCl in the polyion solutions and subsequent dialysis to let the assembly occur. Macrohydrogels formed with an excess of polyanion. In the presence of an excess of polycation, colloidal gels were exclusively obtained. At salt concentrations lower than 1 mol L(-1), the spontaneous gelation provided macro-hydrogels, whatever the polyion in excess. Rheology measurements showed a similar elastic behaviour for CS-DS and CS-HP hydrogels, though CS-HP hydrogels appeared less cohesive. SAXS experiments revealed an aggregate morphology with internal and surface structure depending on the degree of acetylation (DA) of chitosan.
authors.affiliation: Ingénierie des Matériaux Polymères, Université Claude Bernard Lyon 1, Université de Lyon, CNRS UMR 5223 IMP, 15 bd. A. Latarjet, Bât. Polytech Lyon, 69622 Villeurbanne Cedex, France.
authors.forename: M
authors.initials: M
authors.lastname: Costalat
authors.affiliation: Ingénierie des Matériaux Polymères, Université Claude Bernard Lyon 1, Université de Lyon, CNRS UMR 5223 IMP, 15 bd. A. Latarjet, Bât. Polytech Lyon, 69622 Villeurbanne Cedex, France; Centre Technologique des Microstructures, Université Claude Bernard Lyon 1, Université de Lyon, 43 bd du 11 Novembre 1918, 69622 Villeurbanne Cedex, France.
authors.forename: P
authors.initials: P
authors.lastname: Alcouffe
authors.affiliation: Ingénierie des Matériaux Polymères, Université Claude Bernard Lyon 1, Université de Lyon, CNRS UMR 5223 IMP, 15 bd. A. Latarjet, Bât. Polytech Lyon, 69622 Villeurbanne Cedex, France.
authors.forename: L
authors.initials: L
authors.lastname: David
authors.affiliation: Ingénierie des Matériaux Polymères, Université Claude Bernard Lyon 1, Université de Lyon, CNRS UMR 5223 IMP, 15 bd. A. Latarjet, Bât. Polytech Lyon, 69622 Villeurbanne Cedex, France. Electronic address: Thierry.Delair@univ-lyon1.fr.
authors.forename: T
authors.initials: T
authors.lastname: Delair
mesh_terms: D020100:Hydrogels / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D011134:Polysaccharides / Q000737:chemistry*; D013696:Temperature
chemical_list: D020100:Hydrogels; D011134:Polysaccharides
keywords: Chitosan; Dextran sulfate; Heparin; Macro-hydrogel; Nanoparticles; Polyelectrolyte complexes