Materials and methods 
Preparation of silk fibroin/sericin (FIS) solutions. In part 1, silk fibroin (F) solutions were prepared form 2 types of Thai silk cocoons, Bombyk mori Nangnoi Srisaket 1 and Bombyx mori Jul 1/1. Briefly, cocoons of Nangno Srisaket 1 (yellow shell) and Jul 1/1 (white-shell) were degummed in 0.02 M Na2CO3. Dried silk fibroin was dissolved in 93 M LiBr solution at 60°C for 4 h silk fibroin solution was then dialyzed against deionized water for 2 days to remove LiBr and centrifuged at 10,000 rpm, 4°C for 20 min to remove impurities. The final concentration of silk fibroin solution was around 6.5% (w/v) [6]. Commercial sericin powder (heat extraction, Suranaree fibroin solution was around University of Technology) was dissolved in deionized water at 60°C for 30 min and blended with silk fibroin solution at 0,1,2 and 5% sericin.