LAUSR

Protein-based hydrogels are unique materials that combine the durability and wetting properties of polymeric hydrogels with the biocompatibility and elasticity of proteins. Additionally, protein hydrogels present a promising system to probe the mechanical unfolding and refolding of proteins in an ensemble approach. Current rheometry methods apply tensile deformation under constant elongation while tethered materials experience changes in length and tension due to viscoelastic effects. These approaches limit the pulling speed in stress-relaxation experiments and the ability to extract information on the molecular behavior of proteins within hydrogels. Here we introduce a force-clamp (FC) hydrogel rheometer that can measure the extension of protein hydrogels at controlled setpoint forces. We demonstrate this system using protein hydrogels made of bovine serum albumin (BSA), polymerized via a photoactivated reaction. We measure the mechanical response of these hydrogels by maintaining a setforce using an ana...