Fig. 4: Cell co-cultures of the modulated constructs with defined and customized compartments of A containing the combination of MG-63 and BMP-2, and compartment B containing HUVECs, hASCs, and VEGF.

The fabricated scaffold samples with the configuration of an equal aspect ratio for compartment A vs. compartment B was chosen in the study. a The recorded immunofluorescence images of fibrous type-I collagen (COL-I) expression at day 7, day 14, and day 21 indicated guided osteogenic activities in compartment A during the co-cultures. The bone-like nodules formed and increased in size over the indicated period. On the other hand, representative immunofluorescence images of platelet endothelial cell adhesion molecule (PECAM-1/CD31) expression at day 3, day 7, and day 10 showed guided angiogenic activities in compartment B. The classic tube network formed and developed increasingly over the indicated period. b Quantitative analysis of osteogenic activities (n = 4 or 3 independent samples; mean ± SD; unpaired t test; bottom left panel: day 7 vs. day 14 *p = 0.0217 < 0.05, day 14 vs. day 21 *p = 0.0249 < 0.05; bottom right panel: day 7 vs. day 14 *p = 0.0268 < 0.05, day 14 vs. day 21 **p = 0.0043 < 0.01) and c angiogenic activities of the MG-63 and HUVEC co-culture samples containing compartmentalized BMP-2 and VEGF in compartment A and compartment B, respectively (n = 3 independent samples; mean ± SD; unpaired t test; bottom left panel: day 3 vs. day 7 *p = 0.0202 < 0.05, day 7 vs. day 10 **p = 0.0071 < 0.01; bottom right panel: day 3 vs. day 7 **p = 0.0023 < 0.01, day 7 vs. day 10 **p = 0.0079 < 0.01).