(185u) Granules Enable Multiscale Tissue-like Behaviors in Synthetic Hydrogels

Living tissues are an integrated, multi-scale architecture consisting of dense cell ensembles and extracellular matrices (ECM) that cooperate to facilitate excellent mechanical properties and dynamic responsiveness. One key challenge in creating tissue-like materials is the identification of cell-like building blocks that can synergistically respond to external stress with existing ECM-like polymer platforms. Here, we designed a granular material-enabled hybrid gel, featuring cell-like starch granules embedded in ECM-like synthetic hydrogel matrices that readily displayed dynamic memory effects upon mechanical training. Multi-scale and in-situ characterizations revealed that the unique combination of microscopic (chemical bonding) and mesoscopic (physical friction) interactions from starch granules together give rise to tissue-like properties, such as dynamic responsiveness, strain-stiffening, and self-healability. Our results suggest that granular materials, a largely ignored component of biomimetics, may be critical in enabling dynamic behaviors in artificial materials and even in future adaptive and active metamaterials.