Fig. 5.

Osteogenic and chondrogenic differentiation of bone marrow-derived mesenchymal stem cells (MSCs) in GPM hydrogel. (a) Parametric analysis of MSC osteogenic differentiation indicating that stronger and longer dynamic mechanical stimulation (DMS) favored osteogenesis. (b) Strong positive correlation between osteogenesis and external stimulation (ρ, Pearson correlation coefficient). (c) Western blot analysis showing that DMS promoted MSC osteogenesis via FAK pathway. (d) Parametric analysis of MSC chondrogenic differentiation indicating that stronger and longer DMS disfavored chondrogenesis. (e) Strong negative correlation between chondrogenesis and external stimulation (ρ, Pearson correlation coefficient). (f) Western blot analysis showing reduced chondrogenic marker proteins under dynamic conditions. (g) Schematic illustration of osteochondral interface on the knee joint. (h) Photos and microscopic images of bilayer hydrogel for MSC osteo-chondrogenesis. (i) 3D stack image of confocal microscopy showing that MSCs preferentially underwent osteogenesis under DMS and chondrogenesis under static microenvironment. (j,k) The MSC differentiation preferences are represented by the intensity of secreted collagen type I and II in different hydrogel layers, which is related to osteogenesis and chondrogenesis, respectively. Data are expressed as mean ± SD, n = 4.