Aqueous Liquid-Liquid Phase Separation of Resilin-Like Polypeptide/Polyethylene Glycol Solutions for the Formation of Microstructured Hydrogels.

Multiple approaches to generate microstructured hydrogels have emerged in order to control microscale properties for applications ranging from mechanical reinforcement to regenerative medicine. Here, we report new heterogeneous hybrid hydrogels comprising emerging resilin-like polypeptides (RLPs); the hydrogels can be engineered with controlled microstructure and distinct micromechanical properties via the liquid-liquid phase separation (LLPS) of aqueous solutions of the RLPs and poly(ethylene glycol) (PEG). The microstructure in the hydrogels was captured by cross-linking a phase-separated RLP and PEG solution via a Mannich-type reaction with the cross-linker tris(hydroxymethyl phosphine) (THP).

Thiol-ene Photocrosslinking of Cytocompatible Resilin-Like Polypeptide-PEG Hydrogels.

A range of chemical strategies have been used for crosslinking recombinant polypeptide hydrogels, although only a few have employed photocrosslinking approaches. Here, we capitalize on the novel insect protein, resilin, and the versatility of click reactions to introduce a resilin-like polypeptide (RLP) that is capable of photoinitiated thiol-ene crosslinking. Lysine residues of the RLP were functionalized with norbornene acid as confirmed via 1H-NMR spectroscopy.