Granular hydrogels: emergent properties of jammed hydrogel microparticles and their applications in tissue repair and regeneration.

Granular hydrogels are emerging as a versatile and effective platform for tissue engineered constructs in regenerative medicine. The hydrogel microparticles (HMPs) that compose these materials exhibit particle jamming above a minimum packing fraction, which results in a bulk, yet dynamic, granular hydrogel scaffold. These injectable, microporous scaffolds possess self-assembling, shear-thinning, and self-healing properties. Recently, they have been utilized as cell cultures platforms and extracellular matrix mimics with remarkable success in promoting cellular infiltration and subsequent tissue remodeling in vivo. Furthermore, the modular nature of granular hydrogels accommodates heterogeneous HMP assembly, where varying HMPs have been fabricated to target distinct biological processes or deliver unique cargo. Such multifunctional materials offer enormous potential for capturing the structural and biofunctional complexity observed in native human tissue.