Fig. 4.

Cell proliferation and wound healing scratch assay. a, b Proliferation of L929 cells on the surface of the fibroin hydrogels by EdU incorporation. The increased red fluorescence intensity indicated increasing EdU incorporation on the pure fibroin hydrogel or FGF1 solution, compared to blank control. c, d In vitro wound healing assay. The scratched L929 cells seeded on the surface of pure fibroin hydrogels or TCP dishes were cultured with DMEM medium in the presence or absence of FGF1 for 24 h. The cell numbers in the scratched areas increased differently from four groups after 24 h. The results are representative of three independent experiments. Asterisks indicate statistical significance based on Student’s t tests (**P < 0.01, ***P < 0.001)