Multifunctional SDF-1-loaded hydroxyapatite/polylactic acid membranes promote cell recruitment, immunomodulation, angiogenesis, and osteogenesis for biomimetic bone regeneration

Bone repair is a complex and multifactorial regulatory process, and achieving precise and efficient bone regeneration is a fundamental goal of bone tissue engineering. Promoting the synergistic effects of cell recruitment, immunomodulation, angiogenesis, and osteogenesis is a feasible strategy to augment bone repair. In this work, the multifunctional agent stromal cell-derived factor-1 (SDF-1) was loaded onto hydroxyapatite (HAp) nanowires and observed to endow HAp/polylactic acid (PLA) (HP) membrane with versatile capabilities for efficient guided bone regeneration. After being loaded onto HAp nanowires by physical and electrostatic adsorption, SDF-1 showed a relatively rapid release during the early period of bone regeneration and a slow-release during the later period. At the initial stage of bone repair, the SDF-1-HAp/PLA (S-HP) membrane promoted endogenous cell recruitment and macrophage M2 polarization. Later, the S-HP membrane facilitated vessel formation and finally enhanced mature bone regeneration. Therefore, the S-HP membrane could efficiently promote precise and oriented bone tissue regeneration through its synergistic multifunctional effects, demonstrating that this scaffold possesses great potential in guided tissue regeneration and provides guidance for the design of other functional biomaterials.