Growing Hydrogel Organ Mannequins with Interconnected Cavity Structures

Abstract Biomimicking organ mannequins with not only lifelike biological geometries but also virtually constituting connected circulation channels for exchanging substances are critical for in vitro biomedical applications, yet the big challenges remain. This paper reports a big step toward the goal to achieve hydrogel‐based organ mannequins with internal channels and a cavity, gradient structures, and a physiological environment of organs for in vitro purposes via metal ions‐induced interface supramolecular assembly of hydrogel layers on the thermally splitting templates. The templates composed of gelatin and ι‐carrageenan are built through direct ink writing, which are employed as the supports to in situ grow the alginate/Ca 2+ hydrogel layers by rapid diffusion‐induced gelation process. Removing the hydrogel templates based on sol–gel conversion can readily yield hydrogel architectures with connected channels, structural integrity, and favorable physicochemical properties. Proof‐of‐concept hydrogel mannequins including the branched vascular replicas, digestive system, distal lung subunit, and glomerulus with mechanical robustness are engineered from replicating the tubular structure to imitate the basic profiles of organs. It is believed that this protocol paves a versatile way to construct hydrogel‐based biomimicking mannequins with cavity structures that can be used for in vitro biomedical training, testing, pharmacology, etc.