Flexible Self-Powered Respiration Sensor Inspired by Fish Lateral Line Systems

Respiration is a critical physiological signal, and abnormal respiratory patterns are widely recognized as key indicators of various cardiopulmonary and neurological disorders, making continuous monitoring crucial. However, existing clinical systems are constrained by motion limitations, complexity, and cost, hindering daily use. In this work, we present a bio-inspired, low-cost, flexible, and self-powered respiration sensor (BLFS-RS) inspired by the fish lateral line system, operating via contact electrification and electrostatic induction. It features a semicylindrical structure made of silicone rubber, incorporating bionic air channels and a porous-villus composite microstructure. It detects respiratory forces by deforming with abdominal cavity fluctuations, enabling respiration monitoring. Experimental results show that the incorporation of the porous-villus structure increases the sensor's peak output voltage by 556% compared to a nonstructured counterpart. Additionally, the BLFS-RS exhibits high sensitivity (0.88 V/kPa), high durability (300,000 cycles), and fast response time (48 ms). A wearable real-time respiratory monitoring system based on BLFS-RS enables the acquisition of a comprehensive range of human respiratory parameters, including respiratory rate, apnea-hypopnea index, and peak expiratory flow. Furthermore, patients suffering from speech impairments can utilize the BLFS-RS for alternative communication by encoding information through distinct respiratory patterns. This work is expected to provide a viable and sustainable solution for personalized healthcare and remote respiratory monitoring.