Bifunctional Hydrogel-Integrated 3D Printed Scaffold for Repairing Infected Bone Defects

The clinical treatment of infectious bone defects isdifficultand time-consuming due to the coexistence of infection and bone defects,and the simultaneous control of infection and repair of bone defectsis considered a promising therapy. In this study, a dual-drug deliveryscaffold system was fabricated by the combination of a three-dimensional(3D) printed scaffold with hydrogel for infected bone defects repair.The 3D printed polycaprolactone scaffold was incorporated with biodegradablemesoporous silica nanoparticles containing the small molecular drugfingolimod (FTY720) to provide structural support and promote angiogenesisand osteogenesis. The vancomycin (Van)-loaded hydrogel was preparedfrom aldehyde hyaluronic acid (AHA) and carboxymethyl chitosan (NOCC)by the Schiff base reaction, which can fill the pores of the 3D-printedscaffold to produce a bifunctional composite scaffold. The in vitro results demonstrated that the composite scaffoldhad Van concentration-dependent antimicrobial properties. Furthermore,the FTY720-loaded composite scaffold demonstrated excellent biocompatibility,vascularization, and osteogenic ability in vitro.In the rat femoral defect model with bacterial infection, the dual-drugcomposite scaffold showed a better outcome in both infection controland bone regeneration compared to other groups. Therefore, the preparedbifunctional composite scaffold has potential application in the treatmentof infected bone defects.

Automated summary

A dual-drug delivery scaffold system combining a 3D printed scaffold with hydrogel was fabricated for the treatment of infectious bone defects. The scaffold incorporated biodegradable mesoporous silica nanoparticles and vancomycin-loaded hydrogel to provide structural support, promote angiogenesis and osteogenesis, and control infection. In vitro and in vivo experiments showed that the composite scaffold had antimicrobial properties, excellent biocompatibility, and promoted bone regeneration. This bifunctional scaffold has potential application in the treatment of infected bone defects.