Fabrication Of High Strength Hydrogels For Repairing Volumetric Bone Defects

Efficient repair of non-healing volumetric bone defect remains a challenge due to the additional complicated surgery required for fixation.In this thesis,we first synthesized hydrogen bonding crosslinked supramolecular polymer?SP?hydrogels termed as P?NAGA-VPA?by copolymerizing two monomers:hydrogen bonding monomer,N-acryloyl glycinamide?NAGA?and mineralization active monomer,vinylphosphonic acid?VPA?directly in concentrated aqueous solution.The P?NAGA-VPA?hydrogels were then subjected to in situ precipitation mineralization to generate novel high strength mineralized SP hydrogels.The concerted dual physical crosslinkages of NAGA H-bonds and nanocrystal-polymer interaction led to excellent comprehensive mechanical performances of the hydrogels.The mineralized SP hydrogel tubular scaffold was fabricated and encapsulated with bone morphogenetic protein-2?BMP-2?.The BMP-2-loaded mineralized SP hydrogel tube was finely sleeved over the murine radial defect without resorting to any additional surgical fixation.8-weeks implantation outcome demonstrated that this hybrid tubular scaffold contributed to an efficient repair of volumetric bone defect by accelerating new bone formation and seamlessly bonding to the bone surface.To further design a material used for large-size volumetric bone repair,we synthesized a kind of degradable high strength hydrogel named as P?ACG/GelMA?by combining the biodegradability of gelatin methacrylamide?GelMA?and excellent mechanical properties of poly?N-acryloyl 2-glycine??PACG?.The P?ACG/GelMA?hydrogel demonstrated high strength in acidic and neutral environment,while Ca²⁺crosslinking carboxyls could further contributed to the increased mechanical properties.And when immersed inenzymesolutionfor6weeks,theP?ACG/GelMA?hydrogeland P?ACG/GelMA?-Ca hydrogel were completely degraded.The P?ACG/GelMA?hydrogel and P?ACG/GelMA?-Ca hydrogel and their degradation products showed good cytocompatibility at cytotoxicity test in vitro.