Fabricating 3D Printable Self-Oxygenating Hybrid Bioactive Hydrogel Scaffolds for Vascularized Bone Regeneration

Limited cells and growth factors, insufficient mechanical properties, and the hypoxic status in defect areas are the severe challenges faced by bone tissue engineering (BTE) scaffolds, currently. In this work, a 3D printable composite scaffold (Gel-MCM-41-CaO 2 ) without cells or growth factors is designed to promote vascularized bone regeneration through sustained release of oxygen and bioactive ions, utilizing a 1D tube encapsulation release technology to achieve slow release of oxygen from both ends of MCM-41-CaO 2 . Calcium silicate is used as a cross-linking agent and a bioactive agent to cross-link with sodium alginate, combined with polyacrylamide to form a hybrid double network, which endows the hydrogel with excellent compressive strength and 3D printable properties. Based on amounts of data in vitro and in vivo, the oxygen and silicon ions released from this hydrogel scaffold can promote cell proliferation and differentiation, upregulate the expression of osteogenic and angiogenic-related genes, and promote angiogenesis and osteogenesis. This work presents a strategy for fabricating BTE scaffolds without the need for cells or growth factors, with the potential to be applied in clinical bone regeneration and repair.