Research On Preparation And Properties Of Bioactive Glass/Gelatin Methacryloyl Composites Scaffolds

Every year,millions of people suffer from bone defects caused by complex breaks,tumors or traumas,making a significant public health problem.Autografts transplantation is considered as the gold standard for the treatment of bone defects,while its disadvantages such as insufficient donor tissue and donor site morbidity limited the application in clinic.Allografts transplantation is an alternative,but it may result in immune rejection and the risk of pathogen transmission.The appearance and development of bone tissue engineering scaffolds provides effective strategies for the treatment of bone defects.However,bone grafts used in both research and clinic are still inadequate.Therefore,it is critical to develop a new bone repairing scaffold with high bioactivity which can fully meet the clinical requirements.Recently,composites scaffolds made of bioactive glass(BG)and gelatin methacryloyl(GelMA),which focus on mimicking the structure and chemical compositions of natural bone,have been extensively investigated for bone tissue engineering.This study focuses on the preparation and characterization of BG/GelMA composites scaffolds for bone regeneration.There are three sections in the research.Firstly,BG and strontium incorporated BG(Sr-BG)were synthesized by sol-gel method with alkali-catalyzed template.Then,BG/GelMA composites hydrogels were synthesized through a sequential crosslinking with freeze-drying method and the physicochemical and biological properties were investigated.Finally,BG/GelMA/Alginate(Alg)composites scaffolds were synthesized by 3D printing and the effects of Sr-BG on the physicochemical and biological properties of 3D-printed scaffolds were investigated.Firstly,BG and Sr-BG were synthesized by sol-gel method with alkali-catalyzed template.Both BG and Sr-BG possessed good dispersibility and regular spherical shape.In vitro mineralization test showed that BG and Sr-BG had good apatite-forming ability.Then,the composites hydrogels from BG and GelMA prepared by a sequential physical and chemical crosslinking(gelation + UV)approach.The results showed that the compressive modulus of BG/GelMA composites hydrogels increased significantly through the sequential crosslinking approach.The addition of BG resulted in a significant increase in physiological stability and apatite-forming ability.In vitro data indicated that BG/GelMA composites hydrogels promoted cell attachment,proliferation and differentiation.Finally,BG/GelMA/Alg composites scaffolds with highly interconnected porous structure were prepared by 3D printing.In vitro mineralization test showed that the addition of BG and Sr-BG resulted in the significant increase of apatite-forming ability.In vitro data demonstrated that 3D-printed composites scaffolds possessed good biocompatibility.The Sr-BG/GelMA/Alg scaffold showed sustained release of Sr ion and better performance in promoting cell proliferation.