Mechanically Active Contractile Hydrogels for Skin Wound Repair

Polymer hydrogels have been widely explored for wound repair, yet conventional designs remain passive barriers with limited mechanical intervention. Contractile hydrogels address this gap by undergoing network densification and macroscopic shrinkage, which can be converted into wound-edge traction through interfacial adhesion. This review classifies contractile hydrogels into temperature-responsive, pH-regulated, intermolecular-interaction-driven, and solvent-mediated systems according to their dominant contraction mechanisms. The transduction of contraction-derived mechanical cues into biochemical signals is discussed across tissue, cellular, and molecular scales, with emphasis on the well-supported integrin/focal adhesion kinase (FAK)-associated focal adhesion pathway and mechanosensitive ion channels. Current applications in acute full-thickness defects, infected and diabetic chronic wounds, surgical incisions, and scar control are critically surveyed. Finally, key challenges pertaining to force transmission efficiency, spatiotemporal controllability, biosafety, and clinical translatability are discussed. This review aims to provide design guidelines for the rational development of contractile hydrogel platforms for advanced wound management.