Ferritin Nanoshuttle for Long-Lasting Self-Healing of Phenolic Hydrogels

Herein,we highlight a novel finding that ferritin can play a crucialrole in the "self-healing lifetime" of soft phenolicmaterials. Ferritin interacts with a catechol-functionalized polymerto form a self-healable and adhesive hydrogel bidirectionally by providingand retrieving Fe3+. As a result of its unique role asa nanoshuttle to store and release iron, ferritin significantly increasesthe self-healing lifetime of the hydrogel compared with that affordedby catechol-Fe3+ coordination through direct Fe3+ addition without ferritin. Ferritin also induces stableoxidative coupling between catechol moieties following metal coordination,which contributes to double cross-linking networks of catechol-catecholadducts and catechol-Fe3+ coordination. Thus, ferritin-mediatedcross-linking can provide phenolic hydrogels with the advantages ofhydrogels prepared by both metal coordination and oxidative coupling,thereby overcoming the limitations of the current cross-linking methodsof phenolic hydrogels and broadening their versatility in biomedicalapplications.