Self-Calibrated Integrated Sensors Based on Proton Reservoir Functioned Hydrovoltaic Sensing Chip Arrays for Multiplex Sweat Sensing

Wearable integrated sensors enable continuous monitoring of valuable biomarkers without the need for additional equipment or accessories. Utilizing hydrovoltaic sensing chip-based arrays, the concentration of the target analyte can be directly determined through the output voltage, without the requirement for external power sources or the design of reference and counter electrodes. However, hydrovoltaic-based sensing chips are vulnerable to environmental fluctuations, limiting their applicability under dynamic operating conditions. In this work, a proton reservoir-functioned sulfonate-doped polyaniline (SPANI) was used as an active hydrovoltaic sensing material for sweat glucose sensing. Furthermore, a pH self-calibration strategy was developed to eliminate the disturbance generated by dynamic pH fluctuations in the physiological sweat. The real-time pH value of sweat was measured and used to calibrate the difference generated by the pH fluctuations. The resulting integrated sensors enable simultaneous, accurate, and wireless monitoring of sweat glucose levels, pH values, and skin surface temperature. The self-calibrated integrated sensors, based on proton-reservoir-enabled hydrovoltaic sensing chip arrays, demonstrate precise monitoring of multiple health-related parameters in dynamic environments, offering a promising approach for the development of hydrovoltaic-based sensors.