A multifunctional bioactive material that stimulates osteogenesis and promotes the vascularization bone marrow stem cells and their resistance to bacterial infection.

The main limitation of tissue engineering lies in the inability to stimulate osteogenesis, angiogenesis of stem cells and broad-spectrum antimicrobial activity. However, the development of multifunctional bioactive materials with these capabilities remains a great challenge. In this study, we prepared mesoporous silica nanoparticles encapsulated with silver nanocrystals (AG-MSN) with uniform sphere size and mesopores. Platelet-derived growth factor BB (PDGF-BB) was effectively loaded in the AG-MSN mesopores (P-AG-MSN). The silicon ions (Si) released by P-AG-MSN stimulate osteogenic differentiation of bone marrow stromal cells (BMSC) by activating the alkaline phosphatase (ALP) activity of bone-related genes and increasing protein (OCN, RUNX2 and OPN) expression. Ag+ ions could be slowly released from the interior of the shell, highlighting their durable antibacterial activity. The sustained release of PDGF-BB from P-AG-MSN stimulated the angiogenic differentiation of BMSC, as indicated by the enhanced secretion of vascular endothelial growth factor (VEGF), HIF-1α, HGF and ANG-1 and protein expression. Our results show that P-AG-MSN can clearly promote BMSC osteostimulation and vascularization. This research serves as a preliminary study of the utilization of this multifunctional mixture to fabricate a new active biological scaffold that integrates BMSC osteostimulation, vascularization and bactericidal effects by 3D printing technology.