Monitoring Skin Volatile Emissions Using Wearable Sensors

Human skin emits a continuous flux of volatile compounds reflecting various metabolic processes in the body, microbial activity, and environmental factors. Harnessing this emission for diagnostics is of great interest given the noninvasive, passive, and accessible nature of the emission, and there is much research underway to understand the value of this skin-emitted volatile organic compound (VOC) matrix. In parallel to this, wearable skin VOC sensors are emerging and garnering attention due to their potential to provide noninvasive, real-time information for monitoring human health, overcoming many of the design challenges related to biofluid monitoring via wearables. The projected opportunities for skin VOCs are fueling innovations in wearable VOC monitoring. This review discusses the most recent developments, from fully integrated wearable skin VOC sensors that exploit existing semiconductor technology to the design and preparation of advanced new sensing materials and devices to deliver new modalities for wearable skin VOC sensors. We articulate the challenges, limitations, and opportunities for technological advances to provide a perspective on promising directions for future developments.