Periosteum, a membrane covering the surface of the bone, plays an essential role in maintaining the function of bone tissue-and especially in providing nourishment and vascularization during the bone regeneration process. Currently, most artificial periostea have relatively weak mechanical strength and a rapid degradation rate, and they lack integrated angiogenesis and osteogenesis functions. In this study, a bi-layer, biomimetic, artificial periosteum composed of a methacrylated gelatin-nano-hydroxyapatite (GelMA-nHA) cambium layer and a poly (N-acryloyl 2-lycine) (PACG) -GelMA-Mg 2+ fibrous layer was fabricated via 3D printing. The GelMA-nHA layer is shown to undertake the function of improving osteogenic differentiation of rat bone marrow mesenchymal stem cells with the sustainable release of Ca 2+ from nHA nanoparticles. The hydrogen-bonding-strengthened P(ACG-GelMA-L)-Mg 2+ hydrogel layer serves to protect the inner defect site and prolong degradation time (60 days) to match new bone regeneration. Furthermore, the released magnesium ion exhibits a prominent effect in regulating the polarization phenotype of macrophage cells into the M2 phenotype and thus promotes the angiogenesis of the human umbilical vein endothelial cells in vitro. This bi-layer artificial periosteum was implanted into a critical-sized cranial bone defect in rats, and the 12-week post-operative outcomes demonstrate optimal new bone regeneration.
It has always been a huge challenge to construct high-strength hydrogels that are composed entirely of natural polymer. In this study, inspired by the structural characteristics of extracellular matrix (ECM),...
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