Angiogenic PolyHIPE Scaffolds Decorated with Extracellular Matrix as Periosteum Substitutes

1.The periosteum is the connective tissue that envelopes bone and contributes to the normal bone healing process. Periosteal grafts have shown excellent success in the treatment of nonunion bone defects but surgical challenges such as donor site morbidity and graft availability have limited their clinical use. Artificial periosteal membranes are being explored as off-the-shelf alternatives, with several groups investigating the use of decellularized tissues or extracellular matrix (ECM)-based strategies for this purpose. In this study, we investigate the use of in vitro-generated, fibroblast-derived ECM to decorate porous biodegradable scaffolds for use as synthetic periosteal grafts. Scaffolds were fabricated using an emulsion templating technique from a blend of polycaprolactone methacrylate (PCL-M) and poly(glycerol sebacate) methacrylate (PGS-M), resulting in membranes with large, interconnected pores (average pore size = 49.6 {+/-} 40.9 {micro}m, average window size = 12.6 {+/-} 6.1 {micro}m) and structural characteristics suitable for soft tissue applications. The BJ5ta fibroblast cell line was cultured on scaffolds for 14 days to deposit ECM, after which constructs were decellularized. When tested in vitro, periosteal-typical cells exhibited a significantly higher growth rate on ECM-decorated scaffolds compared to controls. Additionally, the chick chorioallantoic membrane (CAM) demonstrated that ECM decoration had a positive angiogenic effect. This proof-of-concept study highlights a promising approach to enhance the biological properties of synthetic membranes, while avoiding challenges associated with decellularizing whole tissues.