A Laser-Engraved Wearable Patch Aptasensor Based on Tetrahedral DNA Nanostructures for In Situ Detection of Cortisol in Sweat

Psychological stress is a common complex emotional state in humans, and if it accumulates over a long period of time, it can lead to serious psychological problems. The accurate detection of cortisol, an important indicator of the body’s response to stress, is crucial for health assessment, psychological state analysis, and the diagnosis of stress-related diseases. To this end, this study prepared a wearable electrochemical aptasensor based on tetrahedral DNA nanostructures and gold nanoparticle-modified laser-engraved graphene (LEG), achieving simple, efficient, and noninvasive cortisol detection. Among them, LEG obtained by direct laser irradiation of polyimide is considered an ideal electrode due to its excellent conductivity. Using methylene blue (MB) as the signal molecule, the conformational change induced by the aptamer–cortisol binding alters the distance between MB and the electrode surface, thereby generating a detectable signal change. In addition, microfluidic devices can quickly collect sweat, effectively avoiding evaporation and contamination issues. By integrating laser-engraved electrodes with microfluidic devices, we have achieved in situ monitoring of cortisol in sweat. The sensor exhibits high sensitivity and excellent specificity, with a linear range of 1 pg/mL–1 μg/mL in artificial sweat and a detection limit as low as 1.06 × 10–2 pg/mL. Furthermore, this method has been successfully applied to the in situ detection of cortisol in sweat, demonstrating the broad application prospects of wearable sensors for detecting sweat biomarkers.