Surface modification of polyurethane towards promoting the ex vivo cytocompatibility and in vivo biocompatibility for hypopharyngeal tissue engineering.

Polymeric substrates with good biocompatibility have been widely employed to create a living construct with the complexities of tissue histology and function in the field of tissue engineering. In this study, poly(ester-urethane) (58213, NAT022) was used to be substrate due to its good physical and chemical properties. Proteins like gelatin or silk fibroin were covalently bonded on its surface using method of diamine aminolysis and glutaraldehyde crosslinking, which had been setup in our group in order to improve poly(ester-urethane)'s hydrophilicity and biocompatibility. The modification was proved by the measurements of static and dynamic contact angles and fluorescence detection. The biological properties were evaluated as in vitro cell culture and in vivo transplantation via cell number counting, morphology observation, immunohistochemistry analysis, etc. The results showed that gelatin or silk fibroin grafted membrane displayed good cytocompatibility, i.e. good proliferation and differentiation of human hypopharynx fibroblast and skeletal muscle cell though the control poly(ester-urethane) indicated low toxicity to cells and good biocompatibility, which was also verified in in vivo experiment. After poly(ester-urethane)-silk fibroin was implanted subcutaneously in rat back, it exhibited a better compatibility to peripheral tissue and faster biodegradation than the control poly(ester-urethane) did. This information supplied us valuable knowledge for poly(ester-urethane) to be used as matrix in situ hypopharynx regeneration study.