Fig. 1.

Fabrication and characteristic of the silk fibroin hydrogels. a Photos of silkworm cocoons from P50 strain. b Macroscopic appearance of silk fibroin hydrogel. c, d SEM images of pure silk fibroin hydrogel cross section. e Ratios of the time-dependent water absorption of fibroin hydrogel in PBS (pH 7.4) at room temperature. f In vitro release profile of FGF1 in fibroin hydrogels over 5 days at 37 °C. g Swelling ratio of FGF1for fibroin hydrogels in PBS (pH 7.4) at 37 °C. h Weight loss of fibroin at different degradation time points in PBS (pH 7.4), respectively. Data are shown as mean ± SD (n = 6)