title: Bioresorption mechanisms of chitosan physical hydrogels: a scanning electron microscopy study.
abstract: Tissue-engineered biodegradable medical devices are widely studied and systems must present suitable balance between versatility and elaboration simplicity. In this work, we aim at illustrating that such equilibrium can be found by processing chitosan physical hydrogels without external cross-linker. Chitosan concentration, degree of acetylation, solvent composition, and neutralization route were modulated in order to obtain hydrogels exhibiting different physico-chemical properties. The resulting in vivo biological response was investigated by scanning electron microscopy. "Soft" hydrogels were obtained from chitosan of high degree of acetylation (35%) and by the neutralization with gaseous ammonia of a chitosan acetate aqueous solutions presenting low polymer concentration (Cp=1.6% w/w). "Harder" hydrogels were obtained from chitosan with lower degree of acetylation (5%) and after neutralization in sodium hydroxide bath (1M) of hydro-alcoholic chitosan solutions (50/50 w/w water/1,2-propanediol) with a polymer concentration of 2.5% w/w. Soft and hard hydrogels exhibited bioresorption times from below 10 days to higher than 60 days, respectively. We also evidenced that cell colonization and neo-vascularization mechanisms depend on the hydrogel-aggregated structure that is controlled by elaboration conditions and possibly in relation with mechanical properties. Specific processing conditions induced micron-range capillary formation, which can be assimilated to colonization channels, also acting on the resorption scenario.
authors: Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Ingénierie des Matériaux Polymères (IMP-UMR 5223), 15 Boulevard Latarjet, 69622 Villeurbanne Cedex, France. Electronic address: sebastien.malaise@gmail.com.
authors: Sébastien
authors: S
authors: Malaise
authors: Université de Bordeaux, Bordeaux 33000, France; Inserm U1026, Bioingénierie Tissulaire, Bordeaux 33000, France.
authors: Lila
authors: L
authors: Rami
authors: Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Ingénierie des Matériaux Polymères (IMP-UMR 5223), 15 Boulevard Latarjet, 69622 Villeurbanne Cedex, France.
authors: Alexandra
authors: A
authors: Montembault
authors: Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Ingénierie des Matériaux Polymères (IMP-UMR 5223), 15 Boulevard Latarjet, 69622 Villeurbanne Cedex, France.
authors: Pierre
authors: P
authors: Alcouffe
authors: Université de Lyon, Université Claude Bernard Lyon 1, Centre Technologique des Microstructure, 69622 Villeurbanne Cedex, France.
authors: Béatrice
authors: B
authors: Burdin
authors: Université de Bordeaux, Bordeaux 33000, France; Inserm U1026, Bioingénierie Tissulaire, Bordeaux 33000, France; CHU de Bordeaux, CIC-IT Biomaterials, F-33000 Bordeaux, France.
authors: Laurence
authors: L
authors: Bordenave
authors: CHU de Bordeaux, CIC-IT Biomaterials, F-33000 Bordeaux, France.
authors: Samantha
authors: S
authors: Delmond
authors: Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Ingénierie des Matériaux Polymères (IMP-UMR 5223), 15 Boulevard Latarjet, 69622 Villeurbanne Cedex, France.
authors: Laurent
authors: L
authors: David
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D048271:Chitosan / Q000737:chemistry* / Q000378:metabolism; D005260:Female; D020100:Hydrogels / Q000737:chemistry* / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D018919:Neovascularization, Physiologic / Q000187:drug effects; D019736:Prostheses and Implants; D051381:Rats; D017208:Rats, Wistar; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels; D048271:Chitosan
keywords: Biomaterial; Bioresorption; Capillary; Cell colonization; Hydrogel; Tuneable