Multimodal sponge-based wearable sensor for continuous monitoring of electrochemical and electrophysiological signals during exercise

Abstract

The increasing demand for non-invasive wearable technologies in sports science to track athletic performance has heightened interest in multimodal systems that continuously monitor both physical and biochemical signals. These integrated platforms overcome the limitations of traditional invasive and fragmented monitoring methods, providing comprehensive physiological datasets for a holistic performance assessment. This work introduces a fully flexible epidermal patch utilizing three-dimensional multi-wall carbon nanotube-polydimethylsiloxane sponge electrodes embedded inside skin-conformal microfluidics. The sponge design facilitates electrochemical sensing of sweat glucose and lactate—critical biomarkers for endurance evaluation, while also integrating biophysical sensors for on-demand electrocardiogram and electromyogram acquisition. The three-dimensional porous architecture enhances the electroactive surface area and maintains strain-invariant electrical properties during deformation, ensuring sensitive and accurate signal output. Furthermore, the polydimethylsiloxane-based sponge framework allows for seamless room-temperature integration with silicone substrates without a bonding procedure. Validation during physical exercise demonstrated the synchronous monitoring of muscular activity, cardiac rhythm, and sweat glucose/lactate concentrations. This multimodal platform holds significant potential for establishing correlations between sweat biomarkers and physiological states, ultimately enabling the optimization of athletic performance in real-world settings.