An Ultrathin, Permeable, and Battery‐Free Monolithically Integrated System for Emotion Sensing and Interaction

Emotion regulation is critical for mental and physical health. Biomarkers such as dopamine and cortisol in body fluids are relevant to emotional status, while there is a lack of feasible devices to achieve personalized emotion management with minimized interferences. This study presents an ultrathin and battery‐free monolithically integrated sensing system for wireless tracking of stress‐related biomarkers with human–machine interaction. The system can be printed on a flexible and porous thermoplastic polyurethane (TPU) membrane with a thickness of around 36 µm, exhibiting remarkable air/moisture permeability of 162 mm/s and 1230 g/m 2 /day. It achieves dopamine and cortisol analysis with detection limits down to 0.25 µM and 1.65 nM. An integrated near‐field communication module enables wireless power harvesting and data transmission for continuous stress monitoring during daily activities, accompanied by emotion‐interactive feedback. The proposed printable method enables monolithic integration of multifunctional devices on ultrathin and permeable platforms toward mental health management in a wearable fashion.