Isolation and processing of silk proteins for biomedical applications

Area of Science:

• Biomaterials Science
• Protein Chemistry
• Textile Engineering

Background:

• Silk proteins, fibroin and sericin, offer unique properties for biomedical, cosmetic, and food applications.
• Aqueous silk protein solutions are preferred for various applications, necessitating efficient extraction methods.
• Existing protocols for silk protein extraction vary in efficiency and downstream processing requirements.

Purpose of the Study:

• To evaluate and identify the most efficient and practical methods for extracting silk fibroin and sericin from mulberry and non-mulberry silk cocoons.
• To compare different extraction protocols for yield, purity, and ease of processing.
• To investigate the impact of post-processing on the nanoscale morphology of silk fibroin films.

Main Methods:

• Extraction of sericin using a sodium carbonate salt-boiling system.
• Dissolution of fibroin using lithium bromide for mulberry silk.
• Analysis of protein extraction efficiency across different silk variants (mulberry and non-mulberry).
• Characterization of mulberry silk fibroin film morphology after post-processing.

Main Results:

• The sodium carbonate salt-boiling system proved to be the most efficient method for sericin extraction across all tested silk variants.
• Lithium bromide was effective for dissolving mulberry silk fibroin, but yielded heterogeneous results for non-mulberry species.
• Post-processing techniques were shown to influence the nanoscale morphology of mulberry silk fibroin films.

Conclusions:

• Sodium carbonate offers a universally efficient method for sericin extraction from diverse silk sources.
• Fibroin extraction requires species-specific approaches, with lithium bromide being effective for mulberry silk.
• Understanding extraction and post-processing effects is crucial for fabricating advanced silk-based biomaterials.