Wearable Microneedle-Integrated Distance-Based Paper Device for Transdermal Cortisol and Dopamine Monitoring

This study introduces a wearable microneedle-distance-based paper analytical device (MN-dPAD) for simultaneous transdermal detection of cortisol and dopamine. Through the integration of a biocompatible hydrogel microneedle array with a wax-printed paper device, the device facilitates the minimally invasive sampling of interstitial fluid (ISF) and visual quantification of analytes. Cortisol and dopamine are detected via oxidation-reduction reactions, exhibiting detection limits of 0.25 μg mL<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> and 1.0 ng mL<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>, respectively, with high precision and recovery studies. Compared with existing techniques, MN -dP AD offers user accessibility, simplicity, cost-effectiveness, and does not require complex instruments, thereby presenting a promising tool for point-of-care (POC) testing for stress and its related disorders.