Wearable Piezoelectric Thin-Film Based Breath Sensing Device with Highly Sensitive Ammonia Detection Ability for Examining Kidney Disease

摘要

A wearable barium titanate (BaTiO3) piezoelectric thin film-based breath sensing device with examining kidney disease ability is developed. The device consists of the smart membrane for characterizing exhalation and inhalation during breathing. This membrane consumes zero electrical power for long-term operation and possesses good biocompatibility for monitoring human breath. It directly measures the breath flow momentum with six piezoelectric cantilevers as backbones and also maintains the symmetry of flow velocity profile during measurement. The acquired charge-amplified signals from six piezoelectric cantilevers clearly indicate the inhalation and exhalation starting points and the maximum air flow rates, much better than the measured displacement at the single-point of the cantilever by laser displacement meter. Besides that, the device is integrated with the novel ultra-sensitive zinc oxide (ZnO) nanoparticle-based ammonia sensor. This ammonia sensor has better time response compared with the commercial product and its detection limit reaches 0.05 ppm. The developed device can be operated in two modes: (1) interfacing environmental air to monitor ammonia concentration. (2) assembled with silica and elastic bag to precisely detect exhaled air of human breath for examining kidney disease.