Mussel‐mimetic polysaccharide‐based injectable hydrogels for biomedical applications

With high biocompatibility and degradability, polysaccharide‐based hydrogels are favorable healthcare materials. However, in many biomedical applications, these materials are inconvenient to handle with fixed morphology, unable to closely match the wounds, and easy to detach due to insufficient adhesion. Inspired by the superior wet adhesive properties of marine mussels, researchers have used mussel‐inspired chemistry to create mussel‐mimetic injectable polysaccharide‐based hydrogels that are simple to operate, controllable in shape, and highly adhesive, and have significantly extended their applications such as tissue adhesives, delivery vehicles, tissue engineering scaffolds, and wearable sensors. However, there are few comprehensive reviews on polysaccharide‐based hydrogels with both mussel‐mimetic adhesion and injectability, and few critical analyses of these hydrogels' preparation methods and applications. This review fills this gap and systematically summarizes the preparation strategies for novel mussel‐mimetic injectable polysaccharide‐based hydrogels, including modifying polysaccharides with catechol‐ or pyrogallol‐containing small molecules and leveraging different interactions between catechol‐/pyrogallol‐modified polysaccharides and other substances to form crosslinked hydrogels. Furthermore, recent biomedical applications of injectable catechol‐/pyrogallol‐modified polysaccharide‐based hydrogels are discussed, and their future challenges and research trends are proposed.