A multifunctional scaffold for bone infection treatment by delivery of microRNA therapeutics combined with antimicrobial nanoparticles.

Treating bone infections and ensuring bone repair is one of the greatest global challenges of modern orthopaedics, made complex by antimicrobial resistance (AMR) risks due to long-term antibiotic treatment and debilitating large bone defects following infected tissue removal. An ideal multi-faceted solution would eradicate bacterial infection without long-term antibiotic use while simultaneously stimulating osteogenesis and angiogenesis. Here, we developed a multifunctional collagen-based scaffold that addresses these needs by leveraging the potential of antibiotic-free antimicrobial nanoparticles (copper-doped bioactive glass, CuBG) to combat infection without contributing to AMR in conjunction with microRNA-based gene therapy (utilising an inhibitor of microRNA-138) to stimulate both osteogenesis and angiogenesis. CuBG scaffolds reduced the attachment of gram-positive bacteria by over 80%, showcasing antimicrobial functionality. The antagomiR-138 nanoparticles induced osteogenesis of human mesenchymal stem cells in vitro, and healed a large load-bearing defect in a rat femur when delivered on the scaffold. Combining both promising technologies resulted in a multifunctional antagomiR-138-activated CuBG scaffold inducing hMSC-mediated osteogenesis and stimulating vasculogenesis in an in vivo chick chorioallantoic membrane model. Overall, this multifunctional scaffold catalyses killing mechanisms in bacteria while inducing bone repair through osteogenic and angiogenic coupling, making this platform a promising multi-functional strategy for treating and repairing complex bone infections. This article is protected by copyright. All rights reserved.