Organic-transistor-based biosensors interfaced with human skin for non-invasive perspiration analysis

Portable or wearable biosensors that can monitor physiological conditions from compounds non-invasively collected from bodily fluids have been actively developed to realize predictive preventive personalized medicine. In particular, sweat is attracting much attention as a potential bodily fluid source because it is easily accessible from the human skin surface and contains certain biomarkers partitioned from the blood. However, the concentration of sweat biomarkers is much lower than that in blood, and a highly sensitive biosensor is required to quantify them. Furthermore, a large amount of sweat should be collected for biosensing at any time to achieve continuous monitoring of human health. In this review, we focused on a transistor-type biosensor, which is a highly sensitive and small integrable device for the detection of low levels of sweat biomarkers. The latest findings regarding the relationship between sweat components and diseases are summarized to discuss the potential of sweat components as biomarkers. Furthermore, an interface design between the device and the skin to effectively collect sweat, even at rest, is discussed to present the latest remarkable progress in research concerning continuous sweat collection mechanisms. Portable or wearable devices integrating these challenging technologies will realize evidence-based personalized daily health management by monitoring changes in sweat composition in the future.