Glutaraldehyde Cross-linked Silk Fibroin Films for Controlled Release

Glutaraldehyde (GA) cross-linked silk fibroin (SF) films were prepared and the structural change were investigated by Fourier transform infrared spectroscopy and differential scanning calorimetry. The results were utilized to reveal the influence of GA cross-linking on the release properties of SF materials. It was found that GA induced conformational transition of SF from random coil to beta-sheet and had influence on the interaction between the peptide chains of SF, resulting in great changes in mechanical and dissolution properties, as well as drug release feature of the films With increasing GA content, tensile strength of films first increases and then decreases, reaching a maximum around 7.5 %. The cross-linking was found to increase the flexibility and stability of SF films in water, and reduce the burst release of Rhodamine B, a model compound for small drug. The release of Rhodamine B exhibited a continuous and steady release after the initial burst, of which the release rate had a good linear fit to beta-sheet content in the matrix, suggesting that the silk 11 crystal could be used as a natural regulator for drug release from SF material.