Micromechanical Properties of Microstructured Elastomeric Hydrogels.

Local, micromechanical environment is known to influence cellular function in heterogeneous hydrogels, and knowledge gained in micromechanics will facilitate the improved design of biomaterials for tissue regeneration. In this study, a system comprising microstructured resilin-like polypeptide (RLP)-poly(ethylene glycol) (PEG) hydrogels is utilized. The micromechanical properties of RLP-PEG hydrogels are evaluated with oscillatory shear rheometry, compression dynamic mechanic analysis, small-strain microindentation, and large-strain indentation and puncture over a range of different deformation length scales.

Biocompatibility and Viscoelastic Properties of Injectable Resilin-Like Polypeptide and Hyaluronan Hybrid Hydrogels in Rabbit Vocal Folds.

Vocal fold scar, characterized by alterations in the lamina propria extracellular matrix, disrupts normal voice quality and function. Due to a lack of satisfactory clinical treatments, there is a need for tissue engineering strategies to restore voice. Candidate biomaterials for vocal fold tissue engineering must match the unique biomechanical and viscoelastic properties of native tissue without provoking inflammation.

Microstructured Elastomer-PEG Hydrogels via Kinetic Capture of Aqueous Liquid-Liquid Phase Separation.

Heterogeneous hydrogels with desired matrix complexity are studied for a variety of biomimetic materials. Despite the range of such microstructured materials described, few methods permit independent control over microstructure and microscale mechanics by precisely controlled, single-step processing methods. Here, a phototriggered crosslinking methodology that traps microstructures in liquid-liquid phase-separated solutions of a highly elastomeric resilin-like polypeptide (RLP) and poly(ethylene glycol) (PEG) is reported.

Micromechanical characterization of soft, biopolymeric hydrogels: stiffness, resilience, and failure.

Detailed understanding of the local structure-property relationships in soft biopolymeric hydrogels can be instrumental for applications in regenerative tissue engineering. Resilin-like polypeptide (RLP) hydrogels have been previously demonstrated as useful biomaterials with a unique combination of low elastic moduli, excellent resilience, and cell-adhesive properties. However, comprehensive mechanical characterization of RLP hydrogels under both low-strain and high-strain conditions has not yet been conducted, despite the unique information such measurements can provide about the local structure and macromolecular behavior underpinning mechanical properties.

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).

Opportunities for multicomponent hybrid hydrogels in biomedical applications.

Hydrogels provide mechanical support and a hydrated environment that offer good cytocompatibility and controlled release of molecules, and myriad hydrogels thus have been studied for biomedical applications. In the past few decades, research in these areas has shifted increasingly to multicomponent hydrogels that better capture the multifunctional nature of native biological environments and that offer opportunities to selectively tailor materials properties. This review summarizes recent approaches aimed at producing multicomponent hydrogels, with descriptions of contemporary chemical and physical approaches for forming networks, and of the use of both synthetic and biologically derived molecules to impart desired properties.

One-step formation of responsive "dumbbell" nanoparticle dimers via quasi-two-dimensional polymer single crystals.

We present a facile approach to synthesize "dumbbell" nanoparticle dimers via one-step coupling of nanoparticles and quasi-two-dimensional polymer single crystals. These dimers exhibit responsive properties enabled by flexible polymeric linkers.