Multimodal Wearable Platform with Simultaneous Electrochemical and Biophotonic Sensing

Multimodal wearables that combine biochemical and physical sensors offer unique opportunities to enhance the efficacy and personalization of care. This could offer new insights into the interrelationships between correlated physiological dynamics, such as the interaction between sweat biomarkers and cardiovascular activity during physical exertion. Few wearables offer sensing solutions beyond a single modality, such as motion, temperature, biophotonics, or biopotentials. Herein, we report a modular electrochemical platform that combines electrochemical, biophotonic, temperature, and motion sensing modalities in a single wearable device. We describe this modular platform's compact, low-power design, which supports up to 130 h of duty-cycled potentiostat operation or 15 h of combined electrochemical and biophotonic sensing capability. Weighing ∼10 g, the wearable system is encased in an armband form factor and powered by a 150 mA h lithium polymer battery, ensuring extended use in real-world settings. System performance was characterized for monitoring changes in sweat lactate and pH with sensitivities of -0.34 μA/mM and -72 mV/pH, respectively, along with local tissue oxygenation, heart rate, motion, and temperature. A proof-of-concept human study was conducted with six subjects, presenting the multimodal capabilities of the system to simultaneously monitor physiological markers during a high-intensity exercise protocol and observe the correlation between sweat lactate and local tissue oxygenation during intense physical activity.