Design of a wearable sweat sensor for diagnosing Cystic Fibrosis in children

Cystic Fibrosis is an inherited genetic and debilitating pathology involving respiratory and digestive systems. The excessive production of thick sticky mucus on the outside of the cells is the main consequence of such disease. Mucous obstructs airways and ducts of several organs. So this pathology is cause of various symptoms. Although current treatments allow patient to improve his/her life quality, nowadays life expectation is about of 30 years. Sweat test is the gold standard or screening technique performed in laboratory to diagnose Cystic Fibrosis. Since individuals with this pathology have characteristic high sodium and chloride concentrations in the perspiration, the test is based on measuring concentrations of such electrolytes. False positive diagnoses are recurrent because of errors during the data interpretation. So improving acquisition and processing of sensor data is a primary goal. The authors propose the design of a wearable sweat sensor able to measure the concentration of the two electrolytes assessing suspicion of Cystic Fibrosis. The main contribution of the project is due to a combination of a Tow-Thomas biquadratic cell and a specific control circuit. This latter is devoted to control the effect of perspiration on Na⁺ and Cl^- concentrations.