Wearable Chemical Sensors: Emerging Systems for On-body Analytical Chemistry.

With the emergence of mobile devices and digital medicine, wearable sensors have received tremendous recent attention across many applications related to monitoring the wearer's conditions and surroundings. Existing wearable sensors commonly track the user's mobility and vital signs (steps, heart rate, etc.). The recent introduction of non-invasive chemical sensors, providing continuous monitoring of chemical markers in a non-invasive manner, fills major gaps in wearable sensor technology, as desired for a plethora of applications. This emerging and exciting area of on-body wearable chemical sensing represents a major transition away from common centralized laboratory-based analytical systems involving in-vitro test-tube assays of blood or urine. Such a major revolution has led to a variety of wearable chemical sensors that allow non-invasive continuous monitoring of many important analytes in biofluids, such as sweat, saliva, tears and interstitial fluid (ISF), instead of blood.