Large bone defects remain an unsolved clinical challenge because of the lack of effective vascularization in newly formed bone tissue. 3D bioprinting is a fabrication technology with the potential to create vascularized bone grafts with biological activity for repairing bone defects. In this study, vascular endothelial cells laden with thermosensitive bio-ink were bioprinted in situ on the inner surfaces of interconnected tubular channels of bone mesenchymal stem cell-laden 3D-bioprinted scaffolds. Endothelial cells exhibited a more uniform distribution and greater seeding efficiency throughout the channels. In vitro, the in situ bioprinted endothelial cells can form a vascular network through proliferation and... More
Large bone defects remain an unsolved clinical challenge because of the lack of effective vascularization in newly formed bone tissue. 3D bioprinting is a fabrication technology with the potential to create vascularized bone grafts with biological activity for repairing bone defects. In this study, vascular endothelial cells laden with thermosensitive bio-ink were bioprinted in situ on the inner surfaces of interconnected tubular channels of bone mesenchymal stem cell-laden 3D-bioprinted scaffolds. Endothelial cells exhibited a more uniform distribution and greater seeding efficiency throughout the channels. In vitro, the in situ bioprinted endothelial cells can form a vascular network through proliferation and migration. The in situ vascularized tissue-engineered bone also resulted in a coupling effect between angiogenesis and osteogenesis. Moreover, RNA sequencing analysis revealed that the expression of genes related to osteogenesis and angiogenesis is upregulated in biological processes. The in vivo 3D-bioprinted in situ vascularized scaffolds exhibited excellent performance in promoting new bone formation in rat calvarial critical-sized defect models. Consequently, in situ vascularized tissue-engineered bones constructed using 3D bioprinting technology have a potential of being used as bone grafts for repairing large bone defects, with a possible clinical application in the future.
3D bioprinted BMSCs-laden GelMA hydrogel scaffold, (GB), 3D bioprinting, 3D dual-extrusion bioprinted BMSCs-laden GelMA hydrogel and RAOECs-laden 3P hydrogel scaffold, (GB-3PR), 3D dual-extrusion bioprinted GelMA hydrogel and RAOECs-laden 3P hydrogel scaffold, (G-3PR), 3D printed GelMA hydrogel scaffold, (G), 4′,6-diamidino-2-phenylindole, (DAPI), Alizarin red S, (ARS), Alkaline phosphatase, (ALP), Dulbecco's modified Eagle's medium, (DMEM), Dulbecco's phosphate-buffered saline, (DPBS), Fourier-transform infrared, (FTIR), In situ vascularization, Large segmental bone defects, PLA-PEG-PLA, (3P), RNA sequencing Analysis, Tissue engineering, analysis of variance, (ANOVA), bone mesenchymal stem cells, (BMSCs), bone mineral density, (BMD), bone volume to tissue volume, (BV/TV), complementary DNA, (cDNA), differentially expressed genes, (DEGs), endothelial cells, (ECs), ethylenediamine tetraacetic acid, (EDTA), extracellular matrix, (ECM), fetal bovine serum, (FBS), gelatin methacryloyl, (GelMA), gene ontology, (GO), glyceraldehyde-3-phosphate dehydrogenase, (GAPDH), green fluorescent protein, (GFP), hematoxylin and eosin, (H&E), lithium phenyl-2,4,6-trimethylbenzoylphosphinate, (LAP), micro-computed tomography, (micro-CT), nuclear magnetic resonance, (NMR), optical density, (OD), paraformaldehyde, (PFA), phosphate-buffered saline, (PBS), polyethylene glycol, (PEG), polylactic acid, (PLA), polyvinylidene fluoride, (PVDF), radioimmunoprecipitation assay, (RIPA), rat aortic endothelial cells, (RAOECs), real-time polymerase chain reaction, (RT-PCR), standard deviation, (SD), tissue-engineered bone, (TEB), tris buffered saline with Tween-20, (TBST)
