Chemically cross-linked silk fibroin hydrogel with enhanced elastic properties, biodegradability, and biocompatibility

Abstract

In this study, the synthesis of silk fibroin (SF) hydrogel via chemical cross-linking reactions of SF due to gamma-ray (γ-ray) irradiation was investigated, as were the resultant hydrogel’s properties. Two different hydrogels were investigated: physically cross-linked SF hydrogel and chemically cross-linked SF hydrogel irradiated at different doses of γ-rays. The effects of the irradiation dose and SF concentration on the hydrogelation of SF were examined. The chemically cross-linked SF hydrogel was compared with the physically cross-linked one with regard to secondary structure and gel strength. Furthermore, the swelling behavior, crystallinity, and biodegradation of the SF hydrogels were characterized. To assay cell proliferation, the cell viability of human mesenchymal stem cells on the lyophilized SF hydrogel scaffolds was evaluated, and no significant cytotoxicity against human mesenchymal stem cells was observed.

Keywords:

• silk fibroin
• hydrogels
• biodegradation rate
• gamma irradiation
• cross-linking

Supplementary materials

Figure S1 ATR-IR absorbance spectra of amide I region by FSD.

Notes: ATR-IR absorbance spectra of amide I region by FSD of (A) 2.3% SF C-gel and SF P-gel and (B) 7.9% SF hydrogel before (black) and after (red) maximum swelling of SF C-gel.

Abbreviations: ATR-IR, attenuated total reflectance infrared spectroscopy; FSD, Fourier self-deconvolution; SF, silk fibroin; C-gel, gamma ray induced chemically cross-linked hydrogel.

Table S1 Vibrational band assignments in the amide I region for B. mori SF

Table S2 Loading efficiency of model drugs in SF C-gel and SF P-gel

Acknowledgments

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and Future Planning (2015M2A2A6A03044942).

Disclosure

The authors report no conflicts of interest in this work.