Dissolution and Regeneration of Bombyx mori Silk Fibroin Using Ionic Liquids

• Published in: Journal of the American Chemical Society Vol. 126; no. 44; pp. 14350 - 14351
• Main Authors: Phillips, David M, Drummy, Lawrence F, Conrady, Deborah G, Fox, Douglas M, Naik, Rajesh R, Stone, Morley O, Trulove, Paul C, De Long, Hugh C, Mantz, Robert A
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 10.11.2004
• Subjects: Animals; Applied sciences; Bombyx - chemistry; Crystallization; Exact sciences and technology; Fibroins - chemistry; Hydrogen Bonding; Ions; Natural polymers; Physicochemistry of polymers; Protein Structure, Secondary; Proteins; Solubility; Organic solvent; Optical microscopy; Silk; Ionic solution; Natural fiber; Fibroin; Crystallinity; Solubility limit; X ray diffraction; Surface structure
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja046079f

In this work, the suitability of imidazolium-based ionic liquid solvents is investigated for the dissolution and regeneration of silkworm (Bombyx mori) silk. Within an ionic liquid the anion plays a larger role in dictating the ultimate solubility of the silk. The dissolution of the silk in the ionic liquid is confirmed using wide-angle X-ray scattering. The dissolved silk is also processed into 100 μm-thick, two-dimensional films, and the structure of these films is examined. The rinse solvent, acetonitrile or methanol, has a profound impact on both the topography of the films and the secondary structure of the silk protein. The image depicts a silkworm cocoon dissolved in 1-butyl-3-methylimidazolium chloride and then regenerated as a film with birefringence.