Mechanically robust and stretchable silk/hyaluronic acid hydrogels.

Combining the material and biological properties of hyaluronic acid (HA) and silk fibroin (SF) in a single hydrogel would expand the range of applications available to HA and SF individually. Here, we present a novel strategy to prepare mechanically robust and stretchable SF/HA hydrogels. The hydrogels were prepared from methacrylated HA (MeHA) and SF in aqueous solutions in the presence of a radical initiator. N, N-dimethylacrylamide (DMAA) monomer was also included into the reaction solution as a spacer to connect MeHA's through their pendant vinyl groups. The presence of SF significantly enhances the mechanical strength of HA hydrogels due to its β-sheet domains acting as physical cross-links. The damage in SF network under large strain leads to a significant energy dissipation, which is responsible for the improved mechanical properties of SF/HA hydrogels.