A wearable mechano-acoustic sensor based on electrochemical redox reaction for continuous cardiorespiratory monitoring

This Letter reports a wearable mechano-acoustic sensor for continuous cardiorespiratory monitoring. The sensing mechanism is based on reversible iodide/triiodide ( I − / I 3 −) electrochemical redox reaction on microfabricated platinum electrodes, enabling an ultra-high sensitivity on the detection of mechano-acoustic signals of the cardiorespiratory system. Ecoflex, a flexible silicone rubber, is adopted as the material of the sensor body due to its excellent stretchability, robustness, and skin-compatibility. The developed sensor exhibited a noise floor of 4.5 μg/ Hz at 10 Hz. Detection of heart sounds, lung sounds, and respiration rates was demonstrated.