BMSC-Exosome/CGF Complex Enhances Bone Regeneration

Bone defect repair remains challenging. This study developed GelMA-CGF-EXOs composites integrating autologous CGF (from rat blood) and BMSC-derived EXOs to enhance bone regeneration. CGF and BMSC-derived EXOs were isolated via centrifugation. EXOs were validated by TEM (cup-shaped, 141.8 nm), Western blot (CD9/CD63/Tsg101), and nanoparticle tracking. GelMA-CGF hydrogels (15% optimal concentration) were characterized structurally (SEM/FTIR) and mechanically. BMSC proliferation/adhesion (live/dead/CCK-8) and osteogenic differentiation (ALP/Alizarin red, ALP/Runx2/OPN Western blot) were tested. In vivo, rat calvarial defects (four groups) were evaluated via Micro-CT, histology, and immunofluorescence (OCN/OPN/Runx2) at 4/8 weeks. 1.BMSCs showed spindle morphology, multilineage differentiation, and EXOs exhibited cup-shaped structures (141.8 nm, CD9+/CD63+/Tsg101+). 2.15% GelMA-CGF displayed interconnected pores, improved mechanical strength, reduced degradation (<70% at 30 days), and enhanced BMSC adhesion/proliferation. ALP/Runx2/OPN expression was upregulated, confirming osteogenic potential. 3.GelMA-CGF-EXOs achieved sustained EXO release (72% over 40 days) versus rapid GelMA-EXO release (24 days). CGF-EXO synergy further elevated BMSC proliferation (CCK-8) and osteogenesis (ALP/mineralization). 4.In vivo, GelMA-CGF-EXOs maximized new bone volume (Micro-CT), angiogenesis (H&E/Masson), and OCN/OPN/Runx2 expression versus controls. GelMA-CGF-EXOs synergistically enhance BMSC osteogenesis via sustained bioactive release, demonstrating superior mechanical stability, biocompatibility, and bone regeneration efficacy in vitro/vivo, offering a promising strategy for clinical bone repair. (208 words)