(280h) A Wearable Electrochemical Platform for Non-Invasive Simultaneous Monitoring of Ca2+ and pH

Authors: 
Wearable biosensors have become important for ambulatory care to promote individualsâ?? role on their health by employing personal health system. Recently, many research groups have developed wearable devices for real-time monitoring of various electrolytes and metabolites non-invasively using tattoo and textile-based sensors. Despite recent development of epidermal analysis in body fluids, real-time Ca2+ and pH detections have not been fully explored. Homeostasis of ionized calcium in biofluids is critical for human biological functions and organ systems. Measurement of ionized calcium for clinical applications is not easily accessible due to its strict procedures and dependence of pH. pH balance in body fluids greatly affects metabolic reactions and biological transport systems. Here, we proposed a wearable electrochemical device for continuous monitoring of ionized calcium and pH of body fluids using a disposable and flexible array of Ca2+ and pH sensors integrated with a flexible printed circuit board (FPCB). This enables real-time quantitative analysis of these sensing elements in body fluids. Accuracy of Ca2+ concentration and pH in biofluids measured by the wearable device is demonstrated. Our results show that the wearable sensors are highly sensitive and selective to target ions with high repeatability and stability. Real-time on-body assessment of sweat is also performed, and results indicate that calcium concentration increases with decreasing pH. This platform can be used in non-invasive continuous analysis of ionized calcium and pH in body fluids for disease diagnosis such as primary hyperparathyroidism and kidney-stone diseases.