Bioprinting EphrinB2-Modified Dental Pulp Stem Cells with Enhanced Osteogenic Capacity for Alveolar Bone Engineering

Bioprinting, a technology that allows depositing living cells and biomaterials together into a complex tissue architecture with desired pattern, becomes a revolutionary technology for fabrication of engineered constructs. Previously, we have demonstrated that EphrinB2-modified dental pulp stem cells (DPSCs) are expected to be promising seed cells with enhanced osteogenic differentiation capability for alveolar bone regeneration. In this study, we aimed to bioprint EphrinB2-overexpressing DPSCs with low-concentrated Gelatin methacrylate (GelMA) hydrogels into three-dimensional (3D) constructs. The printability of GelMA (5% w/v) and the structural fidelity of bioprinted constructs were examined. Then, viability, proliferation, morphology, and osteogenic differentiation of DPSCs in bioprinted constructs were measured. Finally, the effect of EphrinB2 overexpression on osteogenic differentiation of DPSCs in bioprinted constructs was evaluated. Our results demonstrated that GelMA (5% w/v) in a physical gel form was successfully bioprinted into constructs with various shapes and patterns using optimized printing parameters. Embedded DPSCs showed round-like morphology, and had a high viability (91.93% ± 8.38%) and obvious proliferation (∼1.9-fold increase) 1 day after printing. They also showed excellent osteogenic potential in bioprinted constructs. In bioprinted 3D constructs, EphrinB2-overexpressing DPSCs expressed upregulated osteogenic markers, including ALP, BMP2, RUNX2, and SP7, and generated more mineralized nodules, as compared with Vector-DPSCs. Taken together, this study indicated that fabrication of bioprinted EphrinB2-DPSCs-laden constructs with enhanced osteogenic potential was possible, and 3D bioprinting strategy combined with EphrinB2 gene modification was a promising way to create bioengineered constructs for alveolar bone regeneration.