Suzelei Montanari

Polysaccharide gels based on chitosan and modified starch: structural characterization and linear viscoelastic behavior.

We investigated the properties of polymeric systems formed by cross-linking chitosan with modified starch (oxidized maltodextrin). Such a macromolecular cross-linker proved to be efficient to react with chitosan with potentially minimal toxicity. The structural characterization of modified starch alone and of the two-polysaccharide reactive systems was performed using (1)H NMR and FTIR. The rheological behaviors of all systems, from solutions to gels, were also characterized. Depending on experimental parameters, such as chitosan concentration, cross-linking pH, degree of oxidation of starch, and molar ratio of reactive groups, different kinds of systems ranging from pure viscoelastic solutions to stiff hydrogels were formed. These versatile systems could be used in biomedical applications because of the good biocompatibility of their constituents.

Polysaccharide-Based Adhesive for Biomedical Applications: Correlation between Rheological Behavior and Adhesion

Adhesion to biological tissues is a challenge especially when the adhesive is in contact with physiological fluids. Abdominal hernia is a disease that often requires the implantation of a mesh within the abdominal wall. To minimize pain and postsurgical complications, gluing the mesh appears to be a convenient method. For this purpose, a bioadhesive system based on solutions of chitosan and modified starch (oxidized maltodextrin) has been developed. Mixtures of these polysaccharides form either viscoelastic solutions or hydrogels, depending on various experimental parameters (chitosan concentration, starch degree of oxidation, molar ratio between amine and aldehyde functions, pH, etc.). An adhesion test was developed to assess the adherence of such systems under conditions similar to the intended use. The rheological behavior of each formulation was correlated to its adherence, and it was found that optimum adhesion is obtained for systems exhibiting an intermediate behavior between the viscoelastic solution and the gel.