Dynamically crosslinked thermoresponsive granular hydrogels

• Published in: Journal of biomedical materials research. Part A Vol. 111; no. 10; pp. 1577 - 1587
• Main Authors: Lee, Hung‐Pang, Cai, Kathy Xiao, Wang, Ting‐Ching, Davis, Ryan, Deo, Kaivalya, Singh, Kanwar Abhay, Lele, Tanmay P., Gaharwar, Akhilesh K.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01-10-2023; Wiley Subscription Services, Inc
• Subjects: 3D printing; Aldehydes; Assembling; Binding sites; Biomaterials; Biomedical materials; Body temperature; Catalysis; cell delivery; Covalent bonds; Crosslinking; drug delivery; dynamic biomaterials; granular hydrogels; Hyaluronic acid; Hydrogels; Jamming; Microgels; Phase transitions; Polymers; Regeneration (physiology); regenerative medicine; Stability; Three dimensional printing; Tissue engineering; cell delivery; granular hydrogels; drug delivery; regenerative medicine; 3D printing; dynamic biomaterials
• ISSN: 1549-3296; 1552-4965
• DOI: 10.1002/jbm.a.37556

Granular hydrogels are a promising biomaterial for a wide range of biomedical applications, including tissue regeneration, drug/cell delivery, and 3D printing. These granular hydrogels are created by assembling microgels through the jamming process. However, current methods for interconnecting the microgels often limit their use due to the reliance on postprocessing for crosslinking through photoinitiated reactions or enzymatic catalysis. To address this limitation, we incorporated a thiol‐functionalized thermo‐responsive polymer into oxidized hyaluronic acid microgel assemblies. The rapid exchange rate of thiol‐aldehyde dynamic covalent bonds allows the microgel assembly to be shear‐thinning and self‐healing, with the phase transition behavior of the thermo‐responsive polymer serving as secondary crosslinking to stabilize the granular hydrogels network at body temperature. This two‐stage crosslinking system provides excellent injectability and shape stability, while maintaining mechanical integrity. In addition, the aldehyde groups of the microgels act as covalent binding sites for sustained drug release. These granular hydrogels can be used as scaffolds for cell delivery and encapsulation, and can be 3D printed without the need for post‐printing processing to maintain mechanical stability. Overall, our work introduces thermo‐responsive granular hydrogels with promising potential for various biomedical applications.