{Reference Type}: Journal Article {Title}: From Free Tissue Transfer to Hydrogels: A Brief Review of the Application of the Periosteum in Bone Regeneration. {Author}: Xin H;Tomaskovic-Crook E;Al Maruf DSA;Cheng K;Wykes J;Manzie TGH;Wise SG;Crook JM;Clark JR; {Journal}: Gels {Volume}: 9 {Issue}: 9 {Year}: 2023 Sep 21 {Factor}: 4.432 {DOI}: 10.3390/gels9090768 {Abstract}: 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.