A Paper-Based Inkjet-Printed Graphene Sensor for Breathing-Flow Monitoring

Continuous monitoring of breathing flow is an essential but often poorly utilized predictor that is causing poor patient outcome. A low-cost, light-weight, easy-to-use, reliable, and disposable breathing sensor is required to bypass the limitations of existing conventional sensors, which are bulky, expensive, and often require experts to handle. In this article, a low-cost, inkjet-printed graphene sensor on a disposable glossy photo-paper substrate is presented for breathing-rate monitoring. The sensor architecture consists of a graphene nanoparticle based thin functional layer on top of a silver nanoparticle based interdigitated conductive pattern. A standard office inkjet-printer was configured with nanoparticle inks and a printed circuit board design software was utilized for the layouts. The sensor was tested in a laboratory environment, and its data were analyzed for different breathing patterns. An empirical model of the sensor was developed using the Cole-Cole impedance model. Test results showed successful detection of breathing rates for different breathing patterns. The prototype sensor provides a low-cost, disposable, and practical solution for frequent breathing pattern recognition.