Soft, wearable devices to monitor electrophysiological signals and gaseous biomarkers

There is an increasing demand for mobile and continuous health monitoring, which has spurred the development of soft wearable electronics. Stretchable and flexible materials and designs offer a way to create comfortable electronics for health monitoring from the skin. In particular, the recording of EP signals from the skin offers critical insights into human health and physiological activities. EP monitors provide information regarding cardiovascular health, eye movements, muscle responses, brain activity, and more. Compared to existing bulky systems reliant on rigid materials, soft materials and designs allow for unobtrusive monitoring. An important component of sensing EP signals from the skin is wearable electrodes. In addition, the integration of these electrodes with a wireless package is key for collecting and transmitting the acquired signals. In this chapter, requirements, materials, and designs for wearable electrodes are discussed. The packaging of electrodes with circuit components is included and a summary of applications and device demonstrations highlights the current progress. Additionally, gas and breath sensors are reviewed as they allow for the detection of chemicals relevant to human health and safety. Current limitations and future directions to build on the current state of health monitoring from the skin are then highlighted.