Low-Intensity Sensitive and High Stability Flexible Heart Sound Sensor Enabled by Hybrid Near-Field/Far-Field Electrospinning

摘要

Low-cost and wearable heart sound sensors can facilitate early detectionand monitoring of cardiovascular and respiratory diseases. Such sensorsare currently limited by either the complexity of fabrication processes or lowsensitivity and reliability for weak signal detection. Here, a hybrid near-field/far-field electrospinning approach is demonstrated that enables low-costfabrication and optimization of triboelectric heterostructures for heart soundsensing. Specifically, by combining the far-field produced highly polarizedand porous polyvinylidene difluoride network for triboelectric electrificationand near-field patterned polyurethane grid spacers for vibration enhancementand charge trapping, the greatly improved sensor output at the heart soundfrequency (50–150 Hz) and intensity (<80 dB) range, demonstrating recordhigh sensitivity of 7027 mV Pa~（?1） and low detection limit of 47 dB. The sensorexhibits excellent stability under both sudden physical disturbance and longtermcycling stress, showing no degradation during 7 h of continuous operation.It is demonstrated that the sensor can be integrated with apparel andcapture high-quality heart sound signals at all five diagnostic auscultationpoints and distinguish characteristic heart sound patterns caused by differentcardiovascular diseases.