Electrochemical Transducer Optimization for Miniaturization and Performance Enhancement for Wearable Cytokine Biosensors

Cytokines are key human health biomarkers, whose levels in sweat significantly correlate with their concentrations in blood, facilitating thus their minimally-invasive monitoring via wearable devices. Nevertheless, their physiological concentrations in sweat down to pM, highlight the need for extremely sensitive detection techniques, with electrochemical platforms showing significant potential, also in view of a facile integration into wearable systems. To allow large sensitivities, there is however an urgent need to optimize the geometry of the electrochemical transducing platform. In this work, a common electrochemical platform for the detection of cytokines, the three-electrode system, was chosen as a transducer platform, fabricated on a flexible substrate, aiming to improve peak currents and current density during cyclic voltammetry by optimizing geometrical parameters with a combined simulative and experimental approach. The experimental findings indicated that a threefold increase in the active area results in a doubled peak current. Moreover, the simulations revealed that with a reduced distance between the working and counter electrode, the redox reaction solely occurs on the working electrode, thus leading to a higher current density in the electrolyte and enhancing sensitivity.