Development of a 3D-printed polycaprolactone/magnesium phosphate composite scaffold functionalized with novel antimicrobial peptides for enhanced bone defect regeneration

The treatment of large-sized infectious bone defects is currently one of the most urgent clinical challenges that need to be addressed in clinical practice. The clinical application of autologous and allogeneic bone grafts faces numerous persistent challenges that remain unresolved. Therefore, there is an urgent need to develop a bone repair scaffold capable of large-scale production, safe for in vivo use, and possessing robust bone repair and anti-infective properties. In this study, a 3D-printed bone repair scaffold was fabricated using a polycaprolactone (PCL) and magnesium phosphate (MgP) composite material. The scaffold subsequently underwent surface modification with the antimicrobial peptide Tet213 with a DOPA tail, ultimately leading to the development of a novel bone repair scaffold named DTet213@PCL/MgP. The experimental results demonstrated that the DTet213@PCL/MgP scaffold exhibited outstanding antibacterial efficacy against Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus), along with superior proliferation and osteogenesis capabilities for MC3T3-E1 preosteoblastic cells. In a rat radial defect model, the scaffold effectively induced new bone formation at the defect site, resulting in rapid bone regeneration. Furthermore, histopathological examination (H&E staining) of major organs confirmed the excellent in vivo biocompatibility and safety profile of the DTet213@PCL/MgP scaffold. In the future, the DTet213@PCL/MgP scaffold represents a novel solution for the treatment of large-scale infected bone defects, capitalizing on its dual functionality in osteogenesis and infection control.