title: Synthesis and structural characterization of chitosan nanogels.
abstract: Colloidal physical gels of pure chitosan were obtained via an ammonia-induced gelation in a reverse phase emulsion. The water weight fraction and the chitosan concentration in the water phase were optimized so as to yield nanogels with controlled particle size and size distribution. The spherical morphology of the nanogels was established by transmission electron microscopy with negative staining. Wide-angle X-ray scattering experiments showed that these gels were partially crystalline. The electrophoretic mobilities of the particles remained positive up to pH 7, above which the particles aggregated due to the charge neutralization. From the investigation on the colloidal stability of these nanogels in various conditions (pH, salt concentration, temperature), an electrosteric stabilization process of the particles was pointed out, related to the conformation of mobile chitosan chains at the gel-liquid interface. Therefore, the structure of the nanogels was deduced as being core-shell type, a gelified core of neutralized chitosan chains surrounded by partially protonated chains.
authors: bioMerieux, Chemin de l'orme, Marcy l'étoile, France.
authors: Fabrice
authors: F
authors: Brunel
authors: Laurent
authors: L
authors: Véron
authors: Catherine
authors: C
authors: Ladavière
authors: Laurent
authors: L
authors: David
authors: Alain
authors: A
authors: Domard
authors: Thierry
authors: T
authors: Delair
mesh_terms: D048271:Chitosan / Q000138:chemical synthesis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D046529:Microscopy, Electron, Transmission; D000080385:Nanogels; D011092:Polyethylene Glycols / Q000138:chemical synthesis* / Q000737:chemistry; D011094:Polyethyleneimine / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000080385:Nanogels; C413692:polyethylene glycol polyethyleneimine nanogel; D011092:Polyethylene Glycols; D011094:Polyethyleneimine; D048271:Chitosan