Exosomes Endow Photocurable 3D Printing 45S5 Ceramic Scaffolds to Enhance Angiogenesis-osteogenesis Coupling for Accelerated Bone Regeneration

The reconstruction of the vascular network is crucial step in bone regeneration. Therefore, effectively modulating angiogenesis-osteogenesis coupling in bone tissue engineering scaffolds is currently an urgent need. In this study, we employed silane coupling agents containing double bonds to modify tetrahedral silicate, resulting in the preparation of a photocurable precursor of 45S5 bioactive glass (PG). PG was utilized as a binding agent for tricalcium phosphate (TCP) powder, and we employed a one-step photocuring 3D printing approach to fabricate PG/TCP (PT) scaffolds. Furthermore, the endothelial progenitor cell-derived exosomes (EPC-exos) was encapsulated by GelMA and anchored onto the PT scaffolds to create exosome-functionalized PT/G@Exos composite scaffolds. In summary, the PT/G@Exos composite scaffold effectively orchestrates the creation of a vascularized bone regeneration microenvironment by releasing EPC-exos, as well as calcium, silicon (Si), and phosphorus (P) elements. This enables an efficient modulation of the angiogenesis-osteogenesis coupling of bioactive scaffolds and accelerates bone regeneration.