Biomimetic SilMA patches with smart suction and macrophage immunoregulation for cascading skin regeneration.

Hydrogel-based biomaterials are promising for diabetic wound closure, facilitating exudate absorption and cell proliferation. However, conventional hydrogel dressings suffer from unsatisfactory adhesion performance. Insufficient interfacial adhesion easily leads to dressing shedding and treatment interruption. By contrast, excessive adhesion induced by chemically bonded adhesive groups may trigger secondary wound damage during dressing replacement. Moreover, macrophage immunoregulation fails to induce its pro-healing phenotype, posing a challenge for diabetic skin regeneration. Inspired by the nature-reversible tentacles of remoras and octopus, we designed a 3D-printed, suction-driven SPM (SilMA/PEGDA/Mg2+) patch. This innovative therapeutic biomimetic patch is based on an interpenetrating network of methacrylated silk fibroin (SilMA), magnesium ion (Mg2+) and poly(ethylene glycol) diacrylate (PEGDA). The 3D-printed microsuction cups demonstrated strong, reversible, on-demand adhesion to wet wounds without causing interadhesion. Furthermore, the Mg2+ integrated SPM enhances mechanical properties, which could enable sustained release and successfully promote macrophage polarization from the pro-inflammatory M1 phenotype toward the pro-healing M2 phenotype. In diabetic mice, the patch achieved reversible adhesion through gentle pressing, thereby avoiding secondary injury. It effectively attenuated inflammation, upregulated VEGF expression, enhanced angiogenesis, and accelerated cascade skin regeneration. These achievements presented a smart, innovative biomimetic suction therapeutic platform that integrates reversible on-demand adhesion with intrinsic macrophage immunomodulation, offering a strategy for treating refractory diabetic wounds.