A Novel Method for Preparation of Silk Fibroin Hydrogels with Significantly Reduced Gelation Time

Hydrogels are considered to be a versatile and desirable material, due to their great ability of water retention, flexibility, viscoelasticity, and good mechanical properties. Silk fibroin (SF) is one of the most abundant biopolymers used for preparation of hydrogels. SF hydrogels can be prepared by self-assembly or induced by physical or chemical cross-linking. Self-assembly of SF hydrogels was shown to be favorable due to its simplicity and the potential harmfulness of chemical cross-linking agents. However, it is often very slow and time-consuming process, which is the main drawback and limitation of SF industrial application. In this study, a novel method of preparing SF hydrogels from aqueous dispersions of SF powder is presented. The results showed that the gelation time is significantly reduced when SF hydrogels are prepared from SF dispersions instead of SF solutions, yet both types of hydrogels had similar rheological and viscoelastic properties, within the investigated concentration range. All prepared hydrogels showed thixotropic behavior and the prevailing of storage modulus in comparison to loss modulus.