Prepare And Research On Galactosylated Chitosan/alginate Liver Tissue Engineering Scaffold Materials

Liver failure will lead to many deaths, although orthotopic liver transplantation is currently the most effective treatment for severe hepatic failure, donor shortage and costly surgical procedure are still the factors limiting its widespread use by patients with liver failure. Recently liver tissue engineering as an alternative to liver transplants has been researched. The article prepared alginate/ galactosylated chitosan scaffold for liver tissue engineering by freeing and lyophilization techniques. Alginate matrix include unstable mechanical properties due to the ion exchange of crosslinked divalent cations with monovalent ,and lack of the specific cell-recognition signals, which enable the anchorage-dependent cells to promote the interaction with the matrix. In order to save these problems, We use galactosylated chitosan complex alginate. The join of the chitosan could promote the adhesive of the hepatocytes ,and the galactose is known as a specific adhesive ligand to asiloglycoprotein receptor of (ASGR), can promote the hepatocytes migration, proliferation , and specific gene expression.The materials prepared by freeing and lyophilization techniques, studied the preparative process of the scaffolds and the main factors of effecting its capability, including the freeing temperature the molecular weight of the chitosan the concentration of the chitosan. The article studied the degration performance of the alginate/ galactosylated chitosan scaffold in vitro, and discussed the mechanism of the materials.Scanning electron micrographs of the ALG/GC scaffolds as a function of the different freeing temperatures indicates: slowing-freezing at—20℃, and the grows of crystals allowed abutment between ice crystal, so the pore sizes is the most big, and interconnected, suitable for the cultivate of cells.The testing performance of the different concentration and different molecular weight of the chitosan, indicate: when the molecular weight of the chitosan is 300000, and the concentration is 4.5%, the porosity and the degration ratio is the best.The conclusion of the degradation shows that: the smaller molecular weight of the chitosan, because of its short molecule chain ,can easily enter into the interstructure of ALG, through the electrostatic interaction, consequently greatly changed the network of the ALG ,so the degradation of the scaffolds is more rapideness. In the process of the degradation ,the amidogen of the chitosan is easier to link with H~+ , so the PH of the Phosphate Buffer Solution gets higher , and the unstable of the ALG due to the ion exchange of crosslinked divalent cations with monovalent, the carboxylic groups can link with H~+ and so on.