Wireless Flexible Potentiometric Microsensors for Temperature-Compensated Sweat Electrolyte Monitoring

Sweat electrolyte analysis using potentiometric systems is a promising approach for continuous health monitoring. However, despite its potential, temperature-induced measurement errors remain a critical challenge, and, to our knowledge, no study has effectively addressed this issue for accurate potentiometric sensing during physiological activities. Here, we present a temperature-compensated flexible microsensor integrated with a wireless potentiometric measurement circuit for real-time sweat analysis. The wearable system features an array of microsensors for simultaneous detection of pH, Na⁺, K⁺, and skin temperature, enabling real-time dynamic temperature compensation. A PEDOT:PSS/graphene ion-to-charge transducer enhances sensitivity through superior electron acceptor properties and an expanded electroactive surface area. The incorporation of a Nafion top layer ensures 2-week-long stability by facilitating selective cation transport while mitigating sensor degradation. With temperature compensation, the wireless wearable device measures an accurate level of electrolytes under extreme temperature variations (8 to 56 °C), including outdoor exercises and exposure to dry saunas, to assess the necessity of temperature correction. This work collectively establishes a robust, high-performance platform for continuous monitoring of sweat biomarkers, thus advancing wearable diagnostic technology for personalized healthcare applications.