Screen-Printed Electrodes Testing for Detection of Potential Stress Biomarkers in Sweat

Detection of stress biomarkers molecules, non-invasively, through (non-induced) sweat sampling is an important research field since sweat is a potential diagnostic fluid for early and continuous human health monitoring, not only for stress-related conditions directly but also for other pathologies (e.g., associated with chronic diseases). The simultaneous detection of multiple potential biomarkers in sweat samples, using simple and low-cost electrochemical methods (detecting patterns or “electrochemical fingerprints”) requiring no sample preparation and its correlation with physiological conditions, is an attractive methodology but not readily achievable. Several of these potential biomarkers’ electrochemical response presents very close oxidation potentials, among other factors that hamper the detection, such as pH dependence of the electrochemical response or partial adsorption on electrode surfaces. Disposable screen-printed electrode materials, with relatively low-cost, could be useful to overcome the difficulties. A set of selected potential stress-related (non-protein) biomarkers (tyrosine, phenylalanine, dopamine, serotonin, and hydrocortisone) was used in the current study for qualitative electrochemical detection on different screen-printed carbon-based electrodes. The detection was attained in simulated sweat solutions and real sweat samples. The goal was to evaluate the electrochemical response on the different surfaces and determine the most suitable carbon-based screen-printed electrodes that may be used in future sensing devices. Graphical Abstract: [Figure not available: see fulltext.]