title: Starch-chitosan hydrogels prepared by reductive alkylation cross-linking.
abstract: Starch-chitosan hydrogels were produced by oxidation of soluble starch to produce polyaldehyde and subsequently cross-linked with chitosan via reductive alkylation. The swelling ratio of starch-chitosan membranes was increased gradually with increasing starch ratio, but it was always lower than the native chitosan. In dry state, starch-chitosan membranes with low starch ratio (0.16, 0.38) showed similar tensile strength values to those of native chitosan while these values decreased with increasing starch ratios (0.73-1.36). Membranes in physiological buffer solution (PBS) gave a tensile modulus between 2.8 and 1.0 MPa, decreasing with increasing starch ratio (0.16-1.36 (Wstarch/Wchitosan)). When the membranes were incubated in PBS only, a moderate weight loss was observed for the first two weeks. Original weights of low starch weight ratio membranes (0-0.38) were at near 85%, while high ratio samples (0.73-1.55) were kept around 70% after three months. However, for the membranes incubated in alpha-amylase solution, very fast weight loss was observed. For low starch ratio membranes (0.16, 0.38, 0.73), the residual original weights were measured to be 11%, 6%, 20%, while for high ratio membranes (1.04 and 1.36) these were 45% and 30%, respectively, after two months of enzyme incubation. Scanning electron microscopy analysis of alpha-amylase degraded membranes exhibited rough surface morphology.
authors.affiliation: 3B's Research Group-Biomaterials, Biodegradables and Biomimetics, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal. turker.baran@dep.uminho.pt
authors.forename: E T
authors.initials: ET
authors.lastname: Baran
authors.forename: J F
authors.initials: JF
authors.lastname: Mano
authors.forename: R L
authors.initials: RL
authors.lastname: Reis
mesh_terms: D000478:Alkylation; D048271:Chitosan; D003432:Cross-Linking Reagents; D020100:Hydrogels; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D013213:Starch; D013718:Tensile Strength
chemical_list: D003432:Cross-Linking Reagents; D020100:Hydrogels; D013213:Starch; D048271:Chitosan