Osteogenic Differentiation in Chitosan-Based Scaffolds via P28 and VEGF Delivery

Repairing large bone defects remains a significant clinical challenge due to the limitations of current treatments, including infection risk, donor site morbidity, and insufficient vascularization. The autograft is still the gold standard for large bone defects. In this study, we developed chitosan-based (CS-based) scaffolds, incorporating with hydroxyapatite (HAp) and fluorapatite (FAp) ceramics, fabricated by UV crosslinking and freeze-drying, and loaded with P28 peptide, alone or in combination with vascular endothelial growth factor (VEGF), to evaluate the effect of dual bioactive factor delivery. We hypothesized that CS-based scaffolds would optimize ceramic composition and co-delivery of P28 and VEGF, and can enhance early-stage osteogenic differentiation and support bone regeneration. The CS-based scaffolds were characterized by their physicochemical properties, including swelling behavior, mechanical strength, porosity, and in vitro degradation. Biological evaluations were performed including cell proliferation assays, ALP activity, ARS staining, and RT-qPCR, to assess osteogenic differentiation. The results showed that the scaffolds had high porosity, excellent swelling behavior, and degraded within 8 weeks. Dual delivery of P28 and VEGF significantly enhanced early osteogenic markers, indicating a complementary effect. These findings demonstrated that CS-based scaffolds with an optimized ceramic ratio and bioactive factor incorporation have the potential to facilitate bone regeneration.