A novel growth process of calcium carbonate crystals in silk fibroin hydrogel system

We report an interesting finding of calcium carbonate (CaCO3) crystal growth in the silk fibroin (SF) hydrogel with different concentrations by a simple ion diffusion method. The experimental results indicate that the CaCO3 crystals obtained from silk fibroin gels with low and high concentrations are all calcites with unusual morphologies. Time-dependent growth study was carried out to investigate the crystallization process. It is believed that silk fibroin hydrogel plays an important role in the process of crystallization. The possible formation mechanism of CaCO3 crystals is proposed. This study provides a better explanation of the influence of silk fibroin concentration and its structure on CaCO3 crystals growth.

► Calcium carbonate crystals are grown into silk fibroin hydrogels.
► Silk fibroin (SF) gels with different concentrations have no effect on CaCO3 polymorph.
► Dissolution and recrystallization are involved in CaCO3 crystallization within SF gel.
► A possible growth mechanism of CaCO3 crystals in SF gel is proposed.