Characterization and deposition behavior of silk hydrogels soaked in simulated body fluid

This paper reports the mineralization ability of semi-interpenetrating networks composed of regenerated silk fibroin and polyacrylamide hydrogels soaked in simulated body fluid (SBF1x). Hydrogels were prepared by polymerization of acrylamide and N,N′-methylenebisacrylamide in silk fibroin solution with a redox pair as initiator. The incorporation of the fibroin within the polyacrylamide matrix was proved by FTIR–ATR spectroscopy. Swelling measurements in saline solution were performed to evaluate the behavior of these hydrogels having various compositions. Mineralization assays in SBF1x solution revealed the presence of apatite-like crystals onto the surface of the silk fibroin/polyacrylamide hydrogels. Cytotoxicity test by extract method revealed that these hydrogels with various contents in silk fibroin have not developed cytotoxic effects on human fibroblast cultures which increases the possibility of their use in biomedical applications. Mechanical compressive tests revealed good strengths for silk fibroin/polyacrylamide hydrogels. In this way, organic–inorganic hybrids analogous to bone structure can be produced under biomimetic conditions and could be further used in biomedical applications.

► The mineralization ability of fibroin and polyacrylamide hydrogels was evaluated. ► Hydrogels were prepared by polymerization of acrylamide in silk fibroin solution. ► Mineralization test showed the presence of apatite crystals onto hydrogels surfaces. ► Fibroin hydrogels have not developed cytotoxic effects on human fibroblast cultures. ► These findings suggest their use in biomedical applications as scaffolds.