Micro-machined stent flow sensor for detecting breathing and heartbeat from airflow in airway of rat

Abstract

Abstract We developed a stent flow sensor using micro-electromechanical systems (MEMS) technology in order to measure airflow in the airways of laboratory animals. An airflow waveform contains a respiration signal produced by lung motion and heartbeats as these functions are physically connected. This enables both respiration and heart functions to be evaluated under unrestrained and unanesthetized conditions during drug development. Using MEMS technology, we fabricated a tube flow sensor based on a thermal principle, and the stent structure was produced by photolithography and wet etching. The fabricated flow sensor and stent were integrated via a connection area on both elements. In the proof-of-concept trial, we verified that the flow sensor was placed in the center of the tube by expanding the stent. We evaluated the flow detection characteristics, sensor output vs flow rate and sensor response and used the developed stent flow sensor to measure the airflow in the airway of a rat. The respiration and heartbeat signals were successfully identified from the airflow waveform by applying Fourier transform analysis.