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

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Regenerative Medicine

Background:

• Developing heterogeneous hydrogels with controllable microstructures and mechanics is crucial for biomimetic materials.
• Existing methods often lack independent control over microstructure and microscale mechanics through single-step processing.

Purpose of the Study:

• To report a phototriggered crosslinking methodology for creating heterogeneous hydrogels with independent control over microstructure and microscale mechanics.
• To demonstrate the potential of these hydrogels in regenerative medicine applications.

Main Methods:

• Utilizing liquid-liquid phase separation of resilin-like polypeptide (RLP) and poly(ethylene glycol) (PEG).
• Employing a phototriggered crosslinking method to trap RLP-rich domains within a PEG continuous phase.
• Characterizing hydrogel composition and mechanical properties using in situ hyperspectral coherent Raman microscopy and atomic force microscopy.

Main Results:

• Achieved independent control over hydrogel microstructure and micromechanics via a single-step process.
• Demonstrated that local mechanical properties evolve over time while bulk modulus remains constant.
• Successfully encapsulated, localized, and maintained the survival of primary cells within the hydrogels.

Conclusions:

• The developed phototriggered crosslinking method offers precise control over heterogeneous hydrogel properties.
• Phase-separated RLP-PEG hydrogels show promise for regenerative medicine due to their tunable mechanics and biocompatibility.