Physically Crosslinked Biocompatible Silk-Fibroin-Based Hydrogels with High Mechanical Performance

Developing hydrogel which combines superior mechanical performance and biocompatibility attracts researchers' attention in recent years. Here, a novel biocompatible hydrogel with excellent mechanical performance, comprised of regenerated silk fibroin (RSF) and hydroxypropyl methyl cellulose (HPMC), is fabricated by simply mixing and heating. It is found that both of compressive modulus and tensile modulus of the optimal RSF/HPMC hydrogel are over 1.0 MPa. Meanwhile, the break energy is up to 3500 J m(-2), which is higher than that of some natural elastomers, such as cartilage, cork, and skin. The investigation of gelation mechanism reveals that more uniformly dispersed crosslinks dominated by smaller -sheet structures, which is attributed to the synergistic effects of hydrogen bonding and hydrophobic interaction between HPMC and RSF molecules, contribute to the superior mechanical performance of RSF/HPMC hydrogel. This biocompatible high strength silk protein based hydrogel diversifies the robust hydrogels and holds a great promise as candidates for load-bearing materials in biomedical field.