Flexible Electrochemical Sensor for Interleukin-6: Toward Wearable Cytokine Monitoring

The detection of cytokines, which are key proteins involved in immune system signaling, is of extreme importance for health monitoring. Among the various cytokines, interleukin-6 (IL-6) is particularly interesting to monitor, also considering that sweat IL-6 levels show a significant correlation with blood levels, in the range of pg/mL. Despite its importance, sensitive and wearable detection of IL-6 in sweat is still lagging behind. In this work, we fabricated and characterized a flexible screen-printed carbon-based three-electrode electrochemical sensor for IL-6 detection. The planar electrochemical sensor was first modified with gold nanoparticles (AuNPs) and then biofunctionalized with thiolated aptamers. The characterization via electrochemical impedance spectroscopy (EIS) demonstrated selective IL-6 detection in the range from 0.2 to 20 pg/mL in artificial sweat, perfectly covering the physiological range of interest. Our results suggest the potential integration of the developed flexible sensor into wearable devices for cytokine monitoring.