Free Periosteal Flaps with Scaffold: An Overlooked Armamentarium for Maxillary and Mandibular Reconstruction

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.

From Free Tissue Transfer to Hydrogels: A Brief Review of the Application of the Periosteum in Bone Regeneration

The periosteum is a thin layer of connective tissue covering bone. It is an essential component for bone development and fracture healing. There has been considerable research exploring the application of the periosteum in bone regeneration since the 19th century. An increasing number of studies are focusing on periosteal progenitor cells found within the periosteum and the use of hydrogels as scaffold materials for periosteum engineering and guided bone development. Here, we provide an overview of the research investigating the use of the periosteum for bone repair, with consideration given to the anatomy and function of the periosteum, the importance of the cambium layer, the culture of periosteal progenitor cells, periosteum-induced ossification, periosteal perfusion, periosteum engineering, scaffold vascularization, and hydrogel-based synthetic periostea.

Ex Vivo Preservation of Ovine Periosteum Using a Perfusion Bioreactor System

Periosteum is a highly vascularized membrane lining the surface of bones. It plays essential roles in bone repair following injury and reconstruction following invasive surgeries. To broaden the use of periosteum, including for augmenting in vitro bone engineering and/or in vivo bone repair, we have developed an ex vivo perfusion bioreactor system to maintain the cellular viability and metabolism of surgically resected periosteal flaps. Each specimen was placed in a 3D printed bioreactor connected to a peristaltic pump designed for the optimal flow rates of tissue perfusate. Nutrients and oxygen were perfused via the periosteal arteries to mimic physiological conditions. Biochemical assays and histological staining indicate component cell viability after perfusion for almost 4 weeks. Our work provides the proof-of-concept of ex vivo periosteum perfusion for long-term tissue preservation, paving the way for innovative bone engineering approaches that use autotransplanted periosteum to enhance in vivo bone repair.