Figure 5.In vitro osteogenic activity of BP-HF scaffolds.(a) Fluorescent images of rat bone mesenchymal stem cells (rBMSCs) after seeding on the HF and BP-HF scaffolds for 24 h (Green: cytoskeleton, blue: nuclei).Scale bars, 200 µm.(b) The cell proliferation of rBMSCs cultured with HF and BP-HF scaffolds for 5 days.(c) Representative images of alkaline phosphatase (ALP) and alizarin red (AR) staining for rBMSCs cultured with HF and BP-HF scaffolds on days 7, 14 and 21.Scale bar, 1 mm.Quantitative analysis of (d) relative ALP activity and (e) calcium deposits mineralized in HF and BP-HF scaffold groups (*p<0.05,**p<0.01,***p<0.001).BP-HF scaffolds significantly promoted the proliferation and osteogenic differentiation of rBMSCs as compared to the pure HF scaffolds.