Mussel-Inspired Adhesive Hydrogels: Chemistry and Biomedical Applications

Adhesive hydrogels are an emerging class of hydrogels that combine three-dimensional hydrated networks with adhesive properties. These properties facilitate intimate tissue-material contact in diverse biomedical applications, enhancing tissue joining, drug transport, and signal transmission. Inspired by the universal adhesiveness of mussel foot proteins, 3,4-dihydroxyphenyl-L-alanine (DOPA) and its analogs have been extensively exploited for the fabrication of adhesive hydrogels, within which the DOPA moieties can not only serve as cross-linking mediators but also participate in various intermolecular and surface interactions to mediate wet adhesion. This mini-review highlights recent achievements in the development of mussel-inspired adhesive hydrogels, focusing on: (1) elucidating DOPA-mediated adhesion mechanisms through nanomechanical characterizations, (2) designing injectable adhesive hydrogels toward applications in drug delivery, hemostasis, and wound closure, which includes in situ gelling liquids and shear-thinning preformed hydrogels, and (3) fabricating tough adhesive hydrogels with enhanced mechanical properties for use in tissue regeneration, biosensing, and bioimaging, with typical examples of nanocomposite and double-network hydrogels. The challenges and prospects in this rapidly developing field are also discussed.