Wearable Sweat Biosystem with Dual Diffusion-Limiting Interface for Dynamic Hyperlactatemia Management in Critical Care

Hyperlactatemia is a critical indicator of tissue hypoperfusion, metabolic dysfunction, and an adverse prognosis in critically ill patients. Yet conventional monitoring depends entirely on intermittent, invasive blood sampling, which cannot capture the dynamic metabolic fluctuations required to guide timely clinical interventions. Herein, we report a wearable sweat-sensing device built on a dual-diffusion-limiting architecture for the continuous and accurate assessment of clinical hyperlactatemia. This system synergistically modulates lactate diffusion in sweat through a silane-network-encapsulated lactate oxidase layer coupled to a polyvinyl chloride layer. This design effectively delays enzyme saturation, extending the linear detection range for sweat lactate to 0–60 mM and thereby fulfilling the stringent requirements of critical care monitoring. The device also integrates real-time pH and temperature calibration to safeguard measurement accuracy in complex physiological environments. Moreover, linear mixed-effects analysis of 82 paired samples from 33 critically ill patients demonstrated a strong association between sweat and blood lactate levels, with a marginal R2 of 0.840. Sweat lactate effectively identified hyperlactatemia and predicted in-hospital mortality, yielding areas under the receiver operating characteristic curve values of 0.943 and 0.785, respectively. The integrated iontophoresis-microfluidics module further ensures high consistency with bedside arterial blood gas analysis, as validated by a marginal R2 of 0.811. Together, these results establish sweat biosensors as a promising platform for continuous metabolic monitoring, resuscitation assessment, and objective prognostic stratification in critical care settings.