The production of soluble regenerated silk fibroin powder with high molecular weight and silk protein-based materials

• Published in: Giant (Oxford, England) Vol. 19; p. 100313
• Main Authors: Gu, Kai, Tong, Yixuan, Mi, Ruixin, Leng, Siyan, Huang, Hanwen, Yao, Jingrong, Chen, Xin, Shao, Zhengzhong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2024; Elsevier
• Subjects: Powder fusion; Regenerated silk fibroin; Spray-dried powder; Powder fusion; Regenerated silk fibroin; Spray-dried powder
• DOI: 10.1016/j.giant.2024.100313
• ISSN: 2666-5425

The aqueous solution of regenerated silk fibroin (RSF) is considered as the raw material to produce various silk protein-based materials, including hydrogel, film, rod and fiber, etc. with significant mechanical properties. However, the aqueous solution of RSF is usually unstable within a few days or even hours in terms of its essential properties, because the conformation of the RSF chain would spontaneously transfer from random coil to β-sheet in water. In this work, we developed a way to harvest the RSF powder through an optimized spray drying method via rapid drying at a relatively low temperature. It was demonstrated that no severe degradation and conformational transition of the RSF chain occurred during powder preparation, and the RSF powder exhibited remarkable solubility in water and long stability at room temperature. Importantly, there are no obvious differences in the mechanical properties of the silk protein-based materials made from the aqueous solution from the spray-dried RSF powder (Sp-RSF) and from fresh RSF solution. Indeed, such amorphous Sp-RSF powder, in which the protein chain was dominated by random coil conformation, not only promised as the raw material for large-scale silk protein-based products in various applications but also provided the basis for fabricating bulk silk protein materials via the untraditional processing of silk fibroin, such as molding with the help of heat and moisture. Regenerated silk fibroin (RSF) aqueous solution is usually harvested via the procedures of degumming, dissolving and dialyzing. Although RSF-based materials have aroused great interest, the storage of RSF aqueous solution remains to be a challenge. A promising strategy by using the spray drying method to harvest RSF powder with little degradation and conformational transition was developed, showing great potential as the raw material in the mass production of silk protein-based products with various applications. [Display omitted]