Effects of nanotopography on stem cell phenotypes

Figure 2 Histological analysis of cell-polymer constructs maintained in adipogenic, chondrogenic, or osteogenic medium. Sections of the constructs were stained with (A,E) oil red O, (B,F) alcian blue, or (C,G) alizarin red, or histochemically stained for alkaline phosphatase (D,H). In adipogenic cultures (E), oil red O-positive lipid droplets were seen, compared to the lack of staining in the control culture (A). In chondrogenic cultures (F), intense alcian blue was seen, showing cells surrounded by a sulfated proteoglycan-rich ECM (F), whereas control cultures (B) showed little staining. In osteogenic cultures (G,H), mineralization (G) and alkaline phosphatase activity (H) were both significantly higher than in control cultures (C,D). Bar: 20 μm (B,F), 40 μm (A,C,E,G), or 80 μm (D,H)[59].