Silk protein-enriched hybrid bone cement enhances osteogenesis and bone regeneration: In vitro and in vivo evidence

Bioactive bone cements are widely used to treat bone defects; however, achieving an optimal balance of biocompatibility, bioactivity, and osteogenic potential remains a major challenge. Incorporating naturally derived bioactive molecules, such as silk proteins, represents a promising strategy to enhance the biological performance of regenerative biomaterials METHODS: This study investigated the physicochemical, in vitro, and in vivo properties of a novel bone cement incorporating hydrolyzed silk proteins. A novel bone cement was prepared by combining a solid phase composed of hydroxyapatite and agalmatolite with a liquid phase containing chitosan and hydrolyzed silk proteins (fibroin and sericin) at concentrations of 1, 10, and 25 wt%. The physicochemical properties of the cements were characterized, and their biological performance was evaluated through in vitro and in vivo experiments RESULTS: The cements containing natural products showed apatite layer formation and calcium ion release. Moreover, physicochemical stability of the cement-fluid interface, pH, wettability, setting times, and bioactivity improved. Cellular proliferation was observed in samples with higher silk concentrations, demonstrating cytocompatibility, which is an essential factor for predicting in vivo performance. In vivo studies showed that increased new bone formation and complete closure of the defect were associated with higher amounts of hydrolyzed silk proteins included in the cements CONCLUSION: The incorporation of hydrolyzed fibroin and sericin significantly improved the osteogenic performance of the developed bone cements by enhancing their physicochemical properties, cytocompatibility, and bone regenerative capacity, demonstrating their potential as bioactive materials for bone repair.