Comparative studies of regenerated water-based Mori, Thai, Eri, Muga and Tussah silk fibroin films

Abstract

Silk materials from different silkworm species can be utilized in various medical and material applications. In this study, five types of silk proteins: Indian Antheraea mylitta (Tussah), Philosamia ricini (Eri), Antheraea assamensis (Muga), Thailand and Chinese Bombyx mori mulberry (Thai, Mori) were successfully regenerated in the aqueous solution and were fabricated into films. Differential scanning calorimetry (DSC) and temperature-modulated DSC were used to identify glass transition temperatures (Tg), heat capacity increments at Tg and degradation temperatures of these silk films. Besides this, the bound water contents and the thermal degradation mechanisms of different silk systems were quantified using thermogravimetric analysis. In addition, Fourier transform infrared spectrometer was also utilized to investigate the structural differences of these silk films. Compared with the mulberry silk films, wild silk films showed higher thermal stabilities, and variable degradation and structural profiles. These comparative studies offered a new pathway to understand the tunable properties of silk-based biomaterials and would provide important insights for the development of novel silk-based functional materials with controllable physical and biochemical properties in the future.