Sweat and Stress: A Flexible Sensor for Real-Time Cortisol Monitoring

A team of researchers has introduced a flexible, wearable sensor that enables noninvasive, high-precision monitoring of cortisol—a key biomarker of psychological stress. Published in npj Flexible Electronics, the device integrates molecularly imprinted polymers (MIP) for cortisol specificity and carbon nanotube (CNT) electrodes to achieve ultra-high sensitivity over a broad detection range (10⁻³ to 10⁴ nM). Sweat is efficiently collected using a porous chitosan hydrogel (PCSH), which serves as a low-cost, adhesive alternative to microfluidic systems. Combined with a flexible printed circuit board and serpentine electrodes, the platform is both robust and skin-friendly. This innovation represents a promising tool for real-time mental stress evaluation and broader physiological state tracking in daily life.