Towards Wearable Sweat Sensing for Glucose and Lactate: Sensors Characterisation

Non-invasive sweat glucose and lactate monitoring has many advantages over conventional blood sampling methods in being comfortable, unobtrusive, and offering continuous tracking. The use of wearable electrochemical sensors is one of the most promising approaches to enable sweat analytes’ sensing without being influenced by ambient light artifacts. Novel low-power implementations of a sweat sensing device promise to offer health and well-being tracking in wearable, battery-operated systems. Multiple challenges remain until this vision can be realized, such as identifying the variation with temperature and sources of drifts and sample evaporation. This work focuses on the investigation and characterization of glucose and lactate electrochemical sensors with the aim of unveiling their implicit materials’ properties, their dependence on temperature and their durability. The sensors were characterized with increasing and decreasing solution concentrations, repeated measures between different sensors to assess the reproducibility, evaluation of sensor degradation overtime and tests to study temperature dependence. The investigation revealed that the sensors are able to detect glucose and lactate with a linear model for concentration in the range of 0mM - 18 mM for glucose and 0mM - 4 mM for lactate. Glucose had a sensitivity of measurement of 0.038 μA/mM while lactate had a sensitivity of 0.87 μA/mM.