Study On The Bilateral Interactions Between Macrophages And Chitosan-based Biomaterials

The host inflammatory reaction is a normal response to injury and the presence of foreign substances. The magnitude and duration of the inflammatory process has a direct impact on material biostability and biocompatibility, hence affecting the efficacy of biomedical devices. Macrophage is a central cell type in directing host inflammatory and immune processes; thus, its response to biomaterials is extremely important in understanding material-mediated host response.In this paper, to determine the effect of biodegradable biomaterial surface chemistry on macrophage behaviors such as adhesion, spread, activation and apoptosis, the rat's celiac macrophages were cultured on a series of chitosan-gelatin membranes, poly(lactic acid), chitosan-g-(lactic acid) and chitosan derivatives membranes. Protein adsorption behavior on chitosan-gelatin membranes was measured by ELISA. Macrophages behaviors were measured by the methods of MTT test, scan electronic microscope, ELISA and electrophoresis.The results indicated that chitosan and gelatin had good hydrophilicity. Many properties of gelatin membranes were improved by the introduction of chitosan, such as the mechanical properties, the swelling properties and biodegradation. Poly(lactic acid) was hydrophobic and its hydrophilicity was enhanced by the introduction of chitosan. The hydrophilicity of chitosan membrane was more enhanced by the introduction of phosphonic group but reduced by the introduction of alkyl group.Protein adsorption behavior was influenced by the factors of hydrophilicity, charged characteristic and structure of water of chitosan-gelatin membranes in swollen state. The cell experiments demonstrated that biomaterial suface chemistry had an obvious impact on the behaviors of macrophages. Hydrophilic and cationic surfaces promoted macrophages adhesion and spread, but surfaces which were too hydrophilic or had too high density of positive charges were not beneficial to macrophages adhesion and spread. All membranes shown low release of TNF-α, indicating no significant activation and inflammation . Macrophages apoptosis was not induced by all membranes, which demonstrated that all membranes had good biocompatibility. Macrophages accelerated the biodegradation of chitosan-gelatin membranes, but had no notable influence on poly (lactic acid) and chitosan derivatives membranes during 10 days culture period.