A 2.5% (w/v) CECS solution was prepared by dissolution of 2.5 g
CECS in 100 mL distilled water. PVA (13.5 g) was dissolved in 150 mL
distilled water at 80 ◦C with vigorous stirring for a period about 4 h,
forming a PVA solution at a concentration of 9% (w/v). The CECS
solution was mixed with the PVA solution at CECS/PVA weight ratio
40/60. Silk fibroin nanoparticles were added into the CECS/PVA
solution at weight ratio 4 or 8% of silk fibroin nanoparticles to
CECS/PVA, dispersed uniformly by stirring at high speed