Abstract
Wearable sweat biosensors offer significant potential for continuous health monitoring, leveraging the diverse array of biomarkers present in sweat. However, the irregular and episodic nature of sweat secretion poses a challenge for passive sampling, underscoring the need for active extraction techniques. Iontophoresis has gained attention as a promising method, though critical parameters—such as current intensity and stimulation duration-remain poorly defined. To address this, we introduced a flexible iontophoretic platform featuring screen-printed silver/silver chloride electrodes on thermoplastic polyurethane (TPU) and a Strat-M® synthetic membrane as a skin analog. The membrane was mounted in a Franz cell-inspired device separating artificial sweat from deionized water. Direct currents from 0.1 to 0.3 mA were applied, and ionic permeation was quantified via periodic cyclic voltammetry of receptor samples. Results showed that ionic permeation increased with time and current, peaking at 0.3 mA after 30 minutes. These findings validated the platform's potential for downstream iontophoretic extraction in wearable diagnostics—enabling on demand sweatbased biomarker access.