In Situ Formation Mechanism and Osteogenic Performance of Dislocation‐Rich Fibrous Octacalcium Phosphate Mediated by Silk Fibroin

Abstract Octacalcium phosphate (OCP) is a biodegradable material with excellent biocompatibility and osteoinductive activity, showing great promise in bone repair applications. Although silk fibroin (SF) demonstrates osteogenic potential and SF‐modified OCP has shown enhanced mineralization and osteogenesis in vitro, the underlying regulatory mechanism remains unclear. In this study, by combining cryo‐transmission electron microscopy analysis and density functional theory (DFT) calculations, the SF‐modified OCP is revealed that possesses a higher density of dislocations. The hydrophobic amino acid sequence of SF induced the formation of edge dislocations via an “adsorption‐epitaxy‐extrusion” mechanism, accompanied by changes in adsorption energy, which facilitated the transformation of OCP into hydroxyapatite (HAp) and enhanced osteoinduction. In vitro experiments further confirmed that SF‐modified OCP enhanced cytocompatibility, promoted ALP and ARS activity, upregulated osteogenic gene expression, and strengthened osteogenic protein expression. This work proposed a novel strategy for modulating defect structures in bioceramics through organic molecules and demonstrated the potential of dislocation‐engineered SF‐OCP for bone defect repair.