Biomimetic periosteum-bone scaffolds with codelivery of BMP-2 and PDGF-BB for skull repair

Tissue engineering employs the use of bioactive materials to facilitate the filling and acceleration of bone defect healing, thereby introducing novel concepts to the field of in situ bone repair. Some studies have shown that periosteum plays an important role in bone regeneration and repair. In this study, biomimetic periosteum-bone scaffolds were prepared by depositing poly-L-lactic acid (PLLA) electrospun fibers on the surface of the gelatin/chitosan cryogel to mimic the bone and periosteum structure, respectively. To improve the bioactivity of the scaffold, bone morphogenetic protein-2 (BMP-2) was loaded into a loose porous mesh-like cryogel, while platelet-derived growth factor-BB (PDGF-BB) was encapsulated in the core of PLLA nanofibers with core-shell structure. Both of these two growth factors were released locally at the site of bone defect, where they exert a synergistic effect on osteogenesis, thereby greatly accelerating bone healing. The in vitro experiments demonstrated that the biomimetic periosteum-bone scaffolds exhibited favourable biocompatibility and osteogenesis ability. Furthermore, the in vivo experiments indicated that the composite scaffold repaired rat skull defects in a more rapid and effective manner. In conclusion, biomimetic periosteum-bone scaffolds with codelivery of BMP-2 and PDGF-BB shows significant potential for bone regeneration.