An epidermal graphene oxide-based RFID sensor for the wireless analysis of human breath

Breath analysis as well as the detection of abnormal respiratory rate can provide important feedback on people's health status. In this contribution we propose a wearable radiofrequency identification (RFID) epidermal device consisting of a flexible open loop antenna, that enables an easy adhesion on the user's skin, coupled with a graphene oxide-based sensor sensitive to the water vapour. The graphene oxide sensor was characterised in reference conditions, while the communication performance of the antenna was estimated by electromagnetic simulations over a human head phantom as well as by means of measurements on a volunteer. Finally, the whole system was experimentally demonstrated to be capable of comfortably detecting the inhalation/exhalation cycles and abnormal patterns of respiration like the apnea and tachypnea conditions by measuring the changes in graphene oxide resistance.