2014 Volume 22 Pages 109-116
Aqueous solution of calcium chloride (CaCl2) is a promising solvent for biomaterial like silk fibroin, thereby offering potential application in industrial purposes. We observed that the silk, produced by larvae of hornets (Vespa), dissolved in an aqueous solution of CaCl2 in the concentration range of 3-6 M. The solubility of hornet silk was the maximum when CaCl2 concentration was 4.5 M. The rate of dissolution of the hornet silk in the aqueous solution of CaCl2 was sensitive to temperature. The hornet silk was found to dissolve in 4.5 M CaCl2 solution even at 20°C. Such high solubility of the hornet silk in the aqueous solution of CaCl2 could be attributed to the low content of β-sheet structure. The silk dissolved in the aqueous solution of CaCl2 within 1 h when the temperature was between 40 and 80°C, and less protein degradation occurred under the aforementioned condition.