A self-forming bone membrane generated by periosteum-derived stem cell spheroids enhances the repair of bone defects.

The periosteum, a highly specialized thin tissue, is instrumental in contributing to as much as 70 % of early bone formation. Recognizing the periosteum's vital physiological roles, the fabrication of a biomimetic periosteum has risen as an auspicious strategy for addressing extensive bone defects. In the study, we obtained such biomimetic periosteum by utilizing periosteum-derived stem cells (PDSCs) spheroids. These spheroids are induced to spontaneously generate a bioactive membrane on a delicate 3D-printed polycaprolactone (PCL) substrate. This process yields a biomimetic periosteum rich in the resources needed for bone repair. The in vitro evaluations demonstrated that this membrane can act as a repository for growth factors and stem cells. The release kinetics confirmed a sustained delivery of BMP-2 and VEGF, which promoted enhanced osteogenesis and angiogenesis in vitro, respectively. The in vivo results further highlighted robust bone regeneration from critical cranial defects upon the application of this biomimetic periosteum. The biomimetic periosteum, easily harvested and potent in bioactivity, presents substantial clinical potential, particularly for the treatment of critical-sized bone defects. STATEMENT OF SIGNIFICANCE: PDSC theoretically demonstrates substantial potential in membrane construction, a value we've harnessed in this pioneering application. By employing cell spheroids, we've successfully integrated a substantial number of cells into the membrane framework. PDSC spheroids exhibit the remarkable ability to self-assemble into functional membranes, endowing them with robust biological capabilities that enhance their performance in biological systems. The in vitro evaluations demonstrated that this membrane can act as a repository for growth factors and stem cells. The in vivo bone repair facilitated by this membrane is notably effective, characterized by superior bone quality and accelerated formation rates. This process mirrors the natural intramembrane ossification, offering a promising approach to bone integration and regeneration.