Development of asymmetric gradational-changed porous chitosan membrane for guided periodontal tissue regeneration

A novel kind of guided tissue regeneration (GTR) barrier membrane has been fabricated using an immersion–precipitation phase inversion technique (IPPI) with biodegradable natural polymer–chitosan. The membrane had an asymmetric gradational-changed porous structure including a dense skin layer, a transition region and a sponge-like porous layer. The concentration of chitosan solution and solvent evaporated time were two key factors that had significant effect on the porosity, average pore size, absorbed water ratio and mechanical properties of the porous membrane. The porous membrane not only degraded but maintaining the structure integrity for 5–6 weeks in the enzyme solution that can meet the demand for GTR. The biological experiment results showed the asymmetric membranes did not cause anaphylactic reaction, hemolysis, cytotoxicity and pyrogenic effect. All of the results indicated that the porous chitosan membrane had excellent biocompatibility and biodegradation, which could be used as a barrier for preventing apical migration of gingival epithelial cells and promoting growth of periodontal ligament cells in periodontal therapy.