Respiratory Monitoring Device Based on Heterogeneously Integrated Highly Thermosensitive and Fast Response Nanosensors

In this work, we present a novel wearable respiratory monitoring device based on a heterogeneously integrated highly thermosensitive and fast-response nanosensor with a flexible substrate. The sensor is designed based on the ultralow thermal capacitance concept, and the fabricated sensor has a dynamic temperature resolution of 0.016 °C and a time response of 20 μs in laser pulse heating tests and a response time of 10.3 ms in water drop experiments. The device has been integrated with a microcontroller unit with wireless function and micro SD card for controlling data acquisition, transmission, and storage. The power consumption of the sensor is only 125 μW so that an 8 h dynamic monitoring is achieved by using a 100 mAh rechargeable battery. The whole device is miniaturized with a small footprint area of 10.9 cm² and a weight of 10.8 g. Acquired data with wavelet transform analysis successfully detected breathing diseases, such as apnea and tachypnea. Furthermore, the temperature variation in breathing is recorded, which provides extra information for a potential disease diagnosis.