| Objective:Bone defects are a common problem in orthopedic clinics with complex causative factors,such as trauma,tumors,infections and congenital diseases.Among them,infected bone defects are the more problematic type and their treatment is mainly based on surgical intervention and antibiotic therapy.However,the current classical autologous bone graft or allogeneic bone graft treatment for repairing bone defects has certain shortcomings,such as postoperative pain in the donor area,insufficient graft bone source,immune rejection,etc.And the increasing rate of bacterial resistance during anti-infection treatment has become a major problem in the treatment of the disease.Therefore,the research and application of 3D printed scaffolds combined with biofunctional materials for bone tissue engineering technology in bone defect repair has received increasing attention in recent years.In this study,polyhydroxyalkanoate(PHA)/β-tricalcium phosphate(β-TCP)3D-printed scaffolds(PT),compounded with copper(Cu)-containing calcium alginate-chitosan hydrogel(CAC),were used,while their physicochemical properties and biofunctional activities,such as characterization,biocompatibility,bone repair and antibacterial capacity,were investigated.Method:PT 3D printed scaffolds were obtained by mixing PHA and β-TCP in a certain ratio and prepared using a 3D printing system,and PT/CAC and PT/CAC/Cu scaffolds were obtained by compounding different hydrogels.Characterization analysis was performed using scanning electron microscopy and infrared spectral analyzer.Biocompatibility in vitro was probed using CCK-8,live/dead cell staining,acute hem olysis assay and cell adhesion scanning electron microscopy.Bone repair capacity in vitro were probed using alkaline phosphatase assay,alizarin red assay,fluorescence quantitative PCR and cellular immunofluorescence assay.Antibacterial properties in vitro were probed using plate coating assay and live/dead bacterial staining.And then bone repair capacity in vivo were probed by Micro CT analysis and staining of tissue sections in a cranial defect model.Antibacterial properties in vitro were probed by plate coating assay in an infection model.Finally,biocompatibility in vivo was probed by staining of tissue sections in visceral and bone defects.Results:We prepared PT 3D printed scaffolds with regular porous structures and successfully compounded CAC and CAC/Cu hydrogels.The initial concentration of Cu with cytotoxicity was determined by ex vivo correlation experiments,and the composite scaffolds with safe biocompatibility were screened.The best osteogenic induction performance of the PT/CAC/Cu scaffold group was confirmed by ex vivo osteogenesis-related experiments.The best antibacterial performance of the PT/CAC/Cu scaffold group was confirmed by ex vivo antibacterial-related experiments.Conclusion:We successfully prepared a copper-containing hydrogel 3D printed scaffold with regular porous structure.The composite scaffold with safe biocompatibility was screened through in vivo and ex vivo related experiments,and proved to have good osteoinductive and antibacterial properties,which is a very promising bone tissue engineering scaffold for the treatment of infected bone defects. |
