Fig. 4

In vitro osteogenic differentiation. a mRNA fold changes of osteogenesis-related genes in 3D-relative to 2D-BMSC constructs after non-induced or osteogenic (osteo-induced) culture for 7 days. Data represent means (n = 3); no significant differences in 3D versus 2D BMSC for any of the genes. b Representative macroscopic and corresponding microscopic images of in vitro mineralization (Alizarin red S) in 2D and 3D BMSC constructs after non-induced or osteo-induced culture for 21 days, scale bars 100 µm. c Quantification of Alizarin red staining via absorbance measurements in non-induced and induced 2D and 3D BMSC constructs; data represent means and SD (n = 3 or 4) of absorbance values relative to the non-induced 2D BMSC group. RUNX2 runt-related transcription factor 2; ALPL alkaline phosphatase, COL1A2, collagen type 1-alpha 2; OCN/BGLAP, osteocalcin