Quaternary ammonium chitosan/N-isopropylacrylamide-based Janus hydrogel with asymmetric adhesive, shrinkable, and...

Conventional wound dressings primarily focus on biochemical regulation, often neglecting the potential benefits of mechanical cues in tissue regeneration. We report a Janus hydrogel (QPJ hydrogel) that synergistically integrates biochemical modulation with temperature-responsive mechanical contraction for advanced chronic wound management. The hydrogel is constructed from quaternary ammonium chitosan (QCS) and N-isopropylacrylamide (NIPAM), with an outer PNIPAM layer that generates a directional contractile stress >25 kPa at physiological temperature. The hydrogel also exhibits broad-spectrum antibacterial efficacy (> 98 % against S. aureus, E. coli, P. aeruginosa, C. albicans, and MRSA) and potent antioxidant capacity (> 92 % DPPH scavenging). In vitro and in vivo studies confirmed that the hydrogel contracts wound edges, suppresses infection, attenuates inflammation, and accelerates tissue regeneration. This mechano-biochemical dual-action platform surpasses conventional dressings and previously reported Janus hydrogels, most of which lack active mechanical functionality.