A wearable potentiometric sensor with integrated salt bridge for sweat chloride measurement

The development of wearable sensors to measure biomarkers in sweat remains a major technological challenge. Here we report on a wearable, potentiometric, thin film sweat chloride sensor. Potentiometric devices provide a relatively simple technology for sweat sensing, however, equilibration between the reference and test solutions is a significant source of error. We have developed a sweat chloride sensor with integrated salt bridge that minimizes equilibration and enables stable measurements over extended periods of time. The sensor shows a very small concentration drift even with small sample volumes. The measurement variation was less than 2 mM at low chloride ion concentration (10 mM) and 5 mM at high concentration (150 mM), spanning the range for healthy individuals and CF patients. Finally, in on-body tests we show that the sweat chloride concentration in healthy individuals is dependent on exercise intensity, indicating that the sensor has a potential for a fitness monitoring applications. (C) 2017 Elsevier B.V. All rights reserved.