Granular Hydrogels as Modular Biomaterials: From Structural Design to Biological Responses.

Over the past decade, granular hydrogels have been widely utilized as a cell-free or cell-laden platform to deliver therapeutics (e.g., cells and drugs) for tissue repair, or as a bioink or supporting bed for bioprinting. Owing to their inherent microporosity and modularity, various granular hydrogels with functional applications for in vivo use have been fabricated to enhance cell infiltration, spreading and migration, harness immune response, and promote tissue regeneration. In this review, an updated overview of the current state-of-the-art is provided for granular hydrogel development, by highlighting the interplay between design parameters and structural characteristics, like porosity, microstructure, rheological behavior, injectability, and degradability, and their influence on biological responses in various biomedical engineering applications.