Figure 7. Cell adhesion and growth on the surface of the sericin hydrogel.

(a) The morphology of mouse myoblast cells (C2C12) growing on the polystyrene surface of the culture dishes (upper panel) and the sericin hydrogel (lower panel) at the different time points after seeding. The cells were initially seeded at the density of 5 × 10⁴ per 35-mm culture dish. Scale bars, 50 μm. (b) Quantification of the adhesion of human umbilical vein endothelial cells (ECV304) on the culture dishes and the sericin hydrogel at 4 and 8 hours after seeding. N.S., not significant. (c) The viability of human umbilical vein epithelial cells (EA.hy926) on the culture dishes and on the surface of the sericin hydrogels at Day 2.5 and Day 4.5 after seeding was assessed using the MTT assay and indicated as the O.D. value at 570 nm. (d) Rhodamine-phalloidin staining for F-actin (red) and DAPI staining (blue) for nuclei of ECV304 cells on the culture dishes (upper panel) and the sericin hydrogel (lower panel). The areas outlined by the orange dotted lines were enlarged to show the well-developed F-actin stress fibers (orange arrowheads) in the cells growing on both surfaces. The photoluminescence from the sericin hydrogels resulted in the slightly grainy images. Scale bars, 50 μm.