Proliferation and tenogenic differentiation of bone marrow mesenchymal stem cells in a porous collagen sponge scaffold

Figure 1 A 3D culture system based on a type I collagen sponge scaffold. A: Type I collagen sponge scaffold; B: Surface topography of the collagen sponge scaffold observed by scanning electron microscopy. Bars = 100 μm; C: Hematoxylin and eosin staining of sectioned bone marrow mesenchymal stem cell-collagen sponge constructs. Orange arrows indicate the cells. Bars = 100 μm; D: Live/dead assay of the scaffolds during the cultivation process. Green indicates the live cells, and red indicates the dead cells. Bars = 100 μm.