A fully integrative multimodal biosensing system for real-time assessment of hypoxic metabolism and pressure ulcers risk

Early-stage pressure ulcer monitoring is critical for patient quality of life and healthcare resource optimization, yet current manual methods are resource-intensive, time-consuming, and inaccurate, while existing wearables only measure superficial parameters and fail to detect early deep tissue damage. To address this gap, we present a fully integrative wearable multimodal microfluidic biosensor system for real-time assessment of hypoxic metabolism and pressure ulcer risk—with distinct advantages in clinical usability and sensing performance—which features autonomous static sweat induction via iontophoresis, integrates four core modules of sweat induction, multimodal sensing, signal processing and wireless communication into a compact, skin-conformal patch, and facilitates an automated "induction-sampling-detection-alert" workflow without external auxiliary devices, making it particularly suitable for bedridden or mobility-impaired populations. Fabricated via low-cost scalable laser processing, the system synergizes electrochemical and near-infrared technologies to concurrently quantify sweat lactate 0–80 mM with a limit of detection (LOD) of 0.75 mM, pH with a near-Nernstian response of 62.8 mV/pH, skin temperature a LOD of 0.086°C, and regional tissue oxygenation (rSO₂), with real-time calibration ensuring accuracy and wireless smartphone connectivity enabling remote monitoring. Electrochemical characterizations and human trials validate reliable tracking of pressure-induced hypoxia-related dynamics, offering a non-invasive, personalized early warning tool with high translational potential. A fully integrative early pressure ulcer monitoring and early warning system has been reported, enabling continuous in situ monitoring of sweat lactate, pH, and local tissue oxygenation through iontophoresis-based sweat extraction and wireless signal transmission. On-body studies using a volunteer venous occlusion experiment validated the system's diagnostic capabilities, demonstrating its potential for monitoring tissue hypoxia at rest and providing early warning for pressure ulcers.