Figure 6.

Osteogenesis induced by the dual gradients of porosity and BMP-2. (a) Schematic showing the bioprinted 3D construct encapsulated with MSCs for the investigation of osteogenic effects of the dual gradients of porosity and BMP-2. (b-d) Immunostaining results of RUNX2 (green) and OCN (red), as well as F-actin (red) of MSCs in the bioprinted bone-like structures at 1, 2, and 4 weeks following osteogenic differentiation. The quantifications show integrated optical densities (IODs) for RUNX2 and OCN in the regions of low-gradient (L), medium-gradient (M), and high-gradient (H). (e) Osteogenic gene expression levels of MSCs in the bioprinted dual-gradient hydrogels at 4 weeks following osteogenic differentiation in the regions of low-gradient (L), medium-gradient (M), and high-gradient (H). (f) ARS staining of bioprinted dual-gradient hydrogels at 4 weeks following osteogenic differentiation in the regions of low-gradient (L), medium-gradient (M), and high-gradient (H). *P < 0.05, **P < 0.01; ^#P < 0.05, ^##P < 0.01; one-way ANOVA (b and c, *, compared with the group of low-gradient, ^#, compared with the group of 1 week; e, compared with the group of low-gradient at 1 week), mean ± s.d. (n = 3).