A Spectroelectrochemical Sweat Sensor for Improved Management of Diabetes Mellitus

Abstract

Despite recent attention, wearable fitness tracking devices (e.g., Garmin®, Fitbit® and Apple Watch®) remain unable to monitor overall human and animal health in real time. Continuous measurement enables: (1) alerts of abnormal status and (2) collection of large datasets to beget better models of human health. Here, we focus on continuous measurement of diabetic status. Presently, diabetic status is assessed through invasive and expensive blood glucose measurements. As such, continuous measurement in this way is impractical. Often, insufficient measurements are collected and diabetic excursions are undetected (especially in children and animals) which can result in severe complications including death. Some noninvasive techniques exist (e.g., Breath - Ketonix® and Urine) and rely on high levels of blood ketone bodies (e.g., acetoacetate (acac), β-hydroxybutyrate (bhb), and acetone) present with dysregulated diabetes. Blood ketone bodies partition into breath, tears, and sweat and enable noninvasive measurement. However, modern noninvasive techniques are subject to significant irreproducibility and inaccuracy which limits their use by diabetic patients. Alternatively, we describe spectroelectrochemical measurement of acac and bhb in sweat through complexation with metal cations generated at the electrode surface. This concept is advantageous as it may enable continuous quantitative measurement by small portable electronics (such as a cell phone or smart watch). Furthermore, this platform may be extended to other biomarkers that partition into sweat that give insight into other aspects of human health (e.g., heart and kidney failure, exercise intensity, and weight loss).