Effect of Silver Sulfadiazine and Metallic Ions on Properties of Thai Silk Fibroin/Gelatin Films for Anti-Bacterial Applications

Abstract

This study aimed to develop Thai silk fibroin/gelatin (SF/GA) films incorporating various concentrations of silver sulfadiazine (SSD) and to investigate the effects of SSD and metallic ions (Ag(I) and Cu(II)) on chemical conformation of the SF/GA films. We found that the incorporation of SSD in the films changed the conformation of silk fibroin protein by increasing β-sheet content. The same phenomena was also observed with the other 2 metallic ions, Ag(I) and Cu(II), incorporated in the SF/GA films. This effect of metallic ions on the SF conformation transition in the SF/GA films may be similar to the phenomenon occurred during natural spinning process of the Bombyx mori silkworm. The SF/GA films incorporating SSD had therefore more stability, less water-insoluble fraction and extended degradation rate than the SF/GA films without SSD due to the higher content of stable β-sheet conformation. When cultured with L929 mouse fibroblast cells according to ISO 10993 part 5 standard, the SF/GA films incorporating SSD at all concentrations showed no cytotoxicity. The SSD released from the films also showed obvious anti-bacterial activity against Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative) bacteria. We suggested that the SF/GA films incorporating SSD may be useful for some medical applications in which anti-bacterial effect was required.