Green Pathway for Processing Non-mulberry Antheraea pernyi Silk Fibroin/Chitin-Based Sponges: Biophysical and Biochemical Characterization

Silk protein fibroin (SF)-based matrices from non-mulberry, and mulberry silkworms are
used for different applications in regenerative medicine. Silk fiber spun by the wild
non-mulberry silkworm Antheraea pernyi (Ap) is also a promising biomedical material,
due to the presence of the inherent tripeptide sequence of Arginine-Glycine-Aspartic
acid (RGD) on the protein fibroin sequences. However, SF derived from the Ap cocoons
still lacks exploitation in the healthcare field due to its poor solubility in the conventional
solvents. This work addresses the application of green chemistry principles, namely the
use of ionic liquids (ILs, 1-butyl-imidazolium acetate) and renewable resources such as
Antheraea pernyi silk fibroin (ApSF) and chitin (Ch), for the fabrication of sponges from
the blends of ApSF and Ch (APC). The formation of β-sheet in different contents during
ApSF/Ch/IL was acquired by exposing gels to methanol/water and ethanol/water. The
sponges were then obtained by freeze-drying. This approach promotes the formation
of both stable and ordered ApSF/Ch-based sponges. The developed sponges show
the suitable porosity and interconnectivity, appreciable swelling degree, and tuneable
viscoelastic compressive properties for tissue engineering applications. Collectively, the
structural properties of these ApSF/Ch-based sponges make them promising candidates
for biomedical applications, namely cartilage regeneration.