High-Strength and Weavable Smart Nanoyarn Fabric for Unconstrained Ballistocardiogram Monitoring in Home Settings

Long-term, comfortable sleep monitoring is essential for maintaining good health, identifying sleep disorders, and preventing chronic diseases. However, the current gold standard, polysomnography (PSG), is impractical for prolonged use due to its reliance on multiple wired physiological sensors, which interfere with natural sleep patterns, as well as its high operational costs. Respiratory and cardiac signals are key parameters for sleep monitoring, and ballistocardiogram (BCG) are physical signals generated with cardiac activity, which can be monitored in an unconstrained way. Herein, a flexible piezoelectric fabric sensor based on polyvinylidene fluoride (PVDF) yarn is developed for unconstrained physiological signal monitoring. The sensor exhibited a tensile strength over 150 MPa, an operational stability of 10000 loading cycles, and a sensitivity of 34 mV/kPa, enabling it to detect subtle vibration signals such as respiration and BCG. Benefiting from the woven architecture of the yarns, the fabric’s durability and comfort are comparable to those of standard bed linens. The sensor enables nonintrusive monitoring of BCG signals even under high static pressure, demonstrating significant potential for long-term home sleep monitoring and personalized health management.