A Wearable Electrochemical Patch for Sustained Local Oxygen Therapy of Chronic Wounds

Wearable bioelectronics are dominated by low-power sensing, whereas effective therapy requires sustained molecular fluxes that conventional soft devices rarely support. A central challenge is simultaneously maintaining solid-solid charge transport, hydration-dependent ionic conduction, and biofluid resistance within a lightweight, fixture-free architecture. Here, we report a vapor-fed electrochemical materials architecture for skin-conformal oxygen delivery. The system integrates a mechanically interlocking 3D current collector/catalyst interface to stabilize electronic transport, femtosecond-laser-defined microchannels to reconstruct vapor-phase mass transport within an all-solid-state membrane electrode assembly, and a phase-selective porous barrier blocking exudate intrusion while preserving gas diffusion. This hierarchical design enables an ultralight (<4 g) patch to operate at high current densities (>100 mA cm^-2), sustaining continuous operation for 735 h to deliver 16.8 L of high-purity (>99%) O₂. The architecture remains stable for >500 h in simulated exudates and supports efficient transdermal oxygen transport across porcine skin. In a rat pressure-ulcer model, short-course treatment accelerates early wound closure 1.7-fold at day 3, enhancing M2 macrophage polarization and vascular normalization. These results establish a materials framework for translating wearable bioelectronics from passive information interfaces to active molecular-delivery systems.