Development of an Electrochemical Microsensor for Monitoring Biomarkers in Sweat for Healthcare Applications

A sensitive, repeatable and reproducible electrochemical microsensor for the detection of biomarkers in sweat via electrochemical impedance spectroscopy was successfully developed. It is based on the conductive polymer PEDOT:PSS as a sensing layer which was made stable in aqueous solutions by adding the crosslinker GOPS. CMD adds a reactive group to the polymer with the goal to quantify the stress-hormone cortisol via affinity-based recognition with antibodies. The influence of the sensor geometries on the measurement results is evaluated and equivalent circuit models are developed. Electrochemical impedance spectroscopy measurements are run in different concentrations of NaCl and cortisol in DI water to characterize the developed sensor. The sensing layer increases the sensors repeatability and sensitivity and decreases the limit of detection to 0.9 ng/mL cortisol. Moreover, the layers are reproducible and robust towards changes in temperature