Noninvasive Clean Room Free Printed Piezoresistive Breath Sensor for Point of Care Application

Respiratory rate (RR) and pattern evaluation are vital parameters for clinical examination and overall assessment of the health status of an individual. Wearable and flexible real-time breath monitoring sensors are promising and advantageous tools that can help in early and quick diagnosis. This work is a single-step cost-effective, stretchable, and comfortable breath sensor with easy fabrication. The developed laser-induced graphene (LIG)-based wearable sensor (LIG-WS) is a kirigami-structured piezoresistive-based respiratory sensor for evaluating variations in breathing patterns. This sensor utilizes the hygroscopic nature of LIG to analyze the breathing pattern and the RR. The flexible breath sensor can be attached to a surgical mask, helping to recognize various diseases, including sleep apnea, asthma, and cardiac arrest. The fabricated sensor has been tested for sensing different types of breathing patterns, such as usual, slow, shallow, and labored. A quick response time of 2.2 s is observed, and the sensitivity has been analyzed at different humidity, temperature, and touch responses. The stability of the sensor is evaluated over 30 days which demonstrated appreciable stability. The sensor has relevance in wearable breath monitoring and medical diagnostics.