Regulated Ion‐Diffusion Hydrogels for Subtle and Multimodal Temperature‐Strain Sensing in Wound Monitoring

ABSTRACT Continuous assessment of wound microenvironment is critical for proactive and effective healing, yet most dressings serve largely as passive barriers while current wearable sensors are often constrained by complex fabrication, single‐parameter sensing, and insufficient sensitivity to small temperature and mechanical variations under wet or dynamic conditions. This work presents a hydrogel‐based bioelectronic patch that bridges ionic thermodynamics and human physiology, capable of continuous, precise, and multimodal wound monitoring. By engineering and exploiting asymmetric ion diffusion within a PVA/PEDOT:PSS/LiCl matrix, we transform a soft hydrogel into a dual‐mode sensor capable of perceiving both thermal and mechanical cues from wound microenvironments with sub‐kelvin precision. Differential interactions between the polymeric network and infused ions give rise to distinct Li + and Cl − diffusion rates, generating a thermodiffusion‐induced voltage in response to subtle temperature gradients down to 0.1 K. Its signal fidelity opens new opportunities for onset diagnosis and intervention of wound infection, which remain undetectable by existing sensors. Concurrently, the hydrogel with ionic conductivity and mechanical robustness conforms to the wound site, transducing small physical strains into stable impedance signals during daily motion. This work showcases the hydrogel's exceptional sensitivity and practicality, marking a significant step forward toward self‐aware wound dressings that diagnose, interpret, and warn in real time.