One-step cured thermo-actuated Janus dressings with active self-peeling for atraumatic acne treatment

Secondary mechanical trauma caused by the manual peeling or passive detachment of conventional adhesive dressings represents a key clinical challenge for fragile wound treatment. Herein, a thermally actuated Janus hydrogel was fabricated via sequential casting and one-step photopolymerization, leveraging macroscopic viscosity contrast and nanofiller kinetic locking. It comprised a poly(N-isopropylacrylamide) (PNIPAM)/LAPONITE® top layer (P-layer) and a GelMA-NBNAGA/LAPONITE®-polydopamine (lD) bottom layer (GN-layer), where GelMA-NBNAGA refers to gelatin modified with maleic anhydride (MA) and N'-(2-nitrobenzyl)-N-acryloyl glycinamide (NBNAGA). By adjusting the thickness of the P-layer (x), the mass ratio of l and D (y), and the concentration of lD (z), hydrogel dressings with optimized adhesion and mechanical properties were prepared and denominated as P_x/GN-l_yD_z. Hydrophobic NB groups can serve as a versatile drug-delivery platform that accommodates diverse therapeutic agents for applications ranging from the rapid release of relatively hydrophilic molecules (salicylic acid) to the sustained release of highly lipophilic molecules (resveratrol or menthol). Most importantly, under mild thermal stimulation (∼45 °C warm water), the rapid shrinking of the P-layer is efficiently transduced to drive the autonomous self-peeling of the entire hydrogel dressing. In vitro and in vivo evaluation confirmed the paradigm of active detachment from the tissue surface without any external pulling force, indicating promising applications for next-generation smart dermatological care.