Effect of Degumming Methods on Structure and Properties of Regenerated Antheraea Pernyi Silk Fibroin Films

Abstract

The extraction of fibroin (degumming) from the silk fibers impacts the properties of silk fibroin. However, the effect of the degumming method on structures and properties of regenerated Antheraea pernyi silk fibroin (ASF) biomaterials has not been investigated in detail. In this study, Na2CO3 and NaHCO3 are selected to remove sericin of Antheraea pernyi silks. The results show that the silk fibroin prepared by NaHCO3 degumming possessed a higher molecular weight, demonstrated by SDS-PAGE and viscosity testing. Na2CO3 degumming produced more low molecular weight silk fibroin protein below 40 kDa, whereas NaHCO3 processing produced more silk fibroin protein above 70 kDa. The increased molecular weight significantly improved the mechanical properties of ASF film. The enzyme degradation results indicated that the degradation rate of ASF film prepared by Na2CO3 degumming was faster in the early stage due to the presence of low molecular weight silk fibroin. After 21 days, the two silk fibroin films showed approximate degradation ratios. These results showed that the degumming conditions have a significant effect on the structure and properties of ASF biomaterials, and provide options for regulating the mechanical properties and degradation rate of ASF biomaterials.