In Raman spectra of regenerated silk fibroin solution obtained by dissolving silk fibroin fibers by lithium thiocyanate and melted Ca(NO3)2, amide I band shifts to 1650 cm−1, several bands at 1231, 1253, 1262 and 1267 cm-1 appear in amide III area and ν c-c skeletal stretching band appears at 1102 or 1101 cm-1. These bands are attributed to β-helix and/or random coil conformation, indicating that the molecular conformation of silk fibroin changes from β-sheet to β-helix and/or random coil. [Tao et al. (2007)]