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

• Published in: Sensors and actuators. B, Chemical Vol. 250; pp. 673 - 678
• Main Authors: Choi, Dong-Hoon, Li, Yi, Cutting, Garry R., Searson, Peter C.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-10-2017; Elsevier Science Ltd
• Subjects: Balancing; Biomarkers; Biosensors; Chloride; Chloride ions; Cystic fibrosis; Error detection; Fitness; Ion concentration; Potentiometric sensor; Sweat; Sweat chloride; Thin films; Wearable computers; Wearable sensor; Wearable technology; Sweat chloride; Cystic fibrosis; Potentiometric sensor; Wearable sensor
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2017.04.129

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•We have developed a wearable potentiometric chloride sweat sensor with integrated salt bridge to minimize equilibration.•We show an accuracy of about 5mM over the range from 10–150mM.•On-body tests show that sweat chloride concentration is dependent on exercise load.
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 2mM at low chloride ion concentration (10mM) and 5mM at high concentration (150mM), 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.