THE GELATION FROM SILK FIBROIN AQUEOUS SOLUTION IN PRESENCE OF COPPER (II) ION

Abstract

The gelation from silk fibroin aqueous solution in the prseence of copper (II) ion was investigated under various conditions (pH and ion concentration). The rate of gelation are closely related to pH and ion concentration of copper (II). The infrared spectra and X-ray analysis showed that the erystals have the cross β structure in all the films formed from the gels. The content of β-form in the gels obtained in the presence of copper II ion does not change after removing the ion by adding ethylenediamineteraacetic acid to the gel. The time depency of the reduced viscocity of silk fibroin aqueous solution was studied in the presence of copper (II) ion with pH below 8.5 In relation between viscosity and standing time, it was observed that after decreasing gradually, the reduced viscosity increased again, and gels were formed. On the basis of the results mentioned above, the effect of copper (II) ion on the random→β denaturation of silk fibroin aqueous solution is discussed.