Photocurable Methacrylated Silk Fibroin/Hyaluronic Acid Dual Macrocrosslinker System Generating Extracellular Matrix-Inspired Tough and Stretchable Hydrogels

Extracellular matrix (ECM) containing interconnected proteins and glycosaminoglycans (GAGs) is a vital component of a tissue. Its gel-like physicochemical architecture is always a model for scientists studying in the fields of material science. Here, inspired from the ECM, soft hydrogels possessing an interconnected protein/GAG network are fabricated. This network comprises silk fibroin (SF) and hyaluronic acid (HA) as a protein and a GAG component, respectively. The interconnection of the SF and HA is performed by using both methacrylated SF (meth-SF) and HA (meth-HA), which behave as macrocroslinkers for a monomer forming a flexible polymer network between the meth-SF and meth-HA. Meth-HA/meth-SF hydrogels can be compressed and stretched up to 95% and 300%, respectively, with fracture stresses varying between kPa to MPa ranges. Furthermore, they have highly frequency-dependent viscoelastic properties above a particular frequency, likewise seen in many cells and tissues. Mechanical and viscoelastic properties of the hydrogels can be easily tuned by changing the methacrylation degree of the HA, and the concentration and the type of the monomer. It is believed that the meth-HA/meth-SF hydrogels prepared within the scope of this study will be good candidates for tissue engineering applications.