Figure 1.

MC3T3-E1 differentiation and matrix mineralization in a dense collagen (DC) hydrogel. (A) Fabrication of DC hydrogels was carried out by plastic compression. The apparatus used to obtain plastic compression is diagrammatically displayed (adapted from [14]). (B) MC3T3-E1 cells were pre-seeded into the collagen hydrogels, and β-glycerophosphate and ascorbic acid were added to provide an osteoblastic differentiation medium. (C) Cells proliferated within the scaffolds and differentiated into osteoblast-like cells. Mineralization of the collagen scaffold by these cells was apparent at day 15. (D) Using this DC gel model, an “osteoid-like” collagen matrix at day 0 was converted into mineralized collagen within the 3D cell culture model (images presented are scanning electron microscopy (SEM), where scale bars are 15 µm and to the right are schematic depictions for illustrative purposes; rosettes for day 15 indicate hydroxyapatite (HA)).