Silicon-Phosphorus-Nanosheets-Integrated 3D-Printable Hydrogel as a Bioactive and Biodegradable Scaffold for Vascularized Bone Regeneration.

Natural bone is a highly vascularized tissue that relies on the vasculature for blood and nutrients supply to maintain skeletal integrity. Bioactive nanomaterials with the capability of improving vascularized bone regeneration are highly demanded for bone tissue engineering. In this work, 2D silicon phosphorus (SiP) is explored as a new kind of bioactive and biodegradable nanomaterial with excellent angiogenesis and osteogenesis, and a 3D printed biohybrid hydrogel of GelMA-PEGDA incorporated with photocrosslinkable SiP-nanosheet (GelMA-PEGDA/SiPAC) is developed to apply on bone tissue engineering. Findings show that the GelMA-PEGDA/SiPAC possessess excellent biocompatibility and biodegradability, and can sustainably release Si and P elements. Compared with the biohybrid hydrogel scaffolds incorporated with black phosphorus nanosheets, the GelMA-PEGDA/SiPAC can further enhance the osteogenesis of mesenchymal stem cells, and tubular networking of human umbilical vascular endothelial cells. In a rat calvarial bone defect model, the superior angiogenesis and osteogenesis induced by GelMA-PEGDA/SiPAC have been confirmed in vivo. The current strategy paves a new way to design a multifunctional SiP nanocomposite scaffold on mediating the osteogenesis and angiogenesis in one system, and provides a bioactive and biodegradable alternative nanomaterial for tissue engineering and regenerative medicine.