Ultrathin and Wearable Microtubular Epidermal Sensor for Real‐Time Physiological Pulse Monitoring

A flexible, stretchable, soft, and ultrathin wearable microtubular sensor that is highly sensitive to mechanical perturbations is developed. The sensor comprises a unique architecture consisting of a liquid‐state conductive element core within a soft silicone elastomer microtube. The microtubular sensor can distinguish forces as small as 5 mN and possesses a high force sensitivity of 68 N⁻¹. The microtubular sensor occupies a tiny footprint of 120 µm in diameter, approximately the cross‐section of a strand of hair. Superior sensing capabilities of the sensor are reported to detect perturbations from pulsatile air flows and demonstrate its applicability in continuous and imperceptible real‐time monitoring of arterial pulse waves.