Abstract:AIM: To prepare ultraviolet (UV)-crosslinked hydrogel serving as a biocompatible orbital filler, and to explore its biological characteristics as well as its efficacy in expanding orbital soft tissue. METHODS: A novel medical hydrogel was fabricated via UV-induced photopolymerization. Its biosafety was assessed through cytotoxicity test, hemolysis assay and cell apoptosis detection. In vivo imaging examinations were conducted to observe the regulatory effect of the prepared hydrogel on orbital tissue development. RESULTS: The target hydrogel was successfully synthesized by photopolymerization, which possessed typical three-dimensional network structure, favorable hydrophilicity, appropriate swelling behavior and satisfactory mechanical performance. Biosafety evaluations confirmed its good biocompatibility with no obvious cytotoxicity, hemolytic reaction or abnormal cell apoptosis observed. In vivo implantation in juvenile rabbit orbits caused no evident pathological changes in major visceral organs. Imaging findings verified that the hydrogel could promote orbital tissue development, exerting reliable orbital expansion effects with favorable biological safety. CONCLUSION: The UV-crosslinked medical hydrogel prepared in this study has stable physicochemical properties and excellent biocompatibility. It can effectively expand orbital tissue.