(568a) Dynamic Hydrogels Based on Modification of Silk Proteins

Biochemical and mechanical interactions between cells and the surrounding extracellular matrix influence cell fate and behavior. Thus, mimicking these features in vitro on a dynamic basis to study cell functions prompted the design of hydrogel biomaterials to provide relevant matrix features, versatility in chemistry and control of functions to study cell and tissue interactions. These designs are based on using silk fibroin protein, with a range of modifications including with second polymers (e.g., gelatin, hyaluronic acid), alternative chemistries, or new surface functionalities (e.g., peptides, cell signaling factors) to tune or control the dynamic features including mechanics and cell responses. Silk is a natural, high molecular weight, amphiphilic protein that self-assembles and forms into mechanically robust, biocompatible, and versatile biomaterials, including hydrogels. We utilize this core protein as a template for chemical and biophysical modifications to modulate hydrogel formation and properties, with this focus on dynamic features. Recent outcomes include enzymatic, “click”, and photo- chemistries, to generate protein-based materials that undergo different gelation mechanisms to generate hydrogels for in vitro cell culture. The versatility of these systems is exploited to mimic cell-extracellular matrix interactions via the incorporation of bioactive peptides and proteins or by altering the mechanical properties of the material to guide cell behavior. Control of these dynamic features is key when studying underlying biology or developing in vitro tissue models of diseases, with longer-term potential translational impact.