Touch-based wearable cortisol monitoring via an interface-engineered hydrogel fiber sensor

Wearable cortisol monitoring offers a noninvasive approach for assessing dynamic physiological stress, but reliable on-body analysis remains challenging owing to limited sweat availability, unstable electrode contact, and use-induced mechanical deformation. Here, we report a compartmentalized multi-lumen, hydrogel-integrated cortisol-sensing fiber (HCSF) for rapid and reliable detection of cortisol in sweat that combines sweat collection, molecular recognition, and wireless readout in a glove-based wearable platform. The interface-engineered interlayer provides topological anchoring for the MIP matrix and promotes efficient charge transfer, while the porous compartmentalized hydrogel sheath functions as an in situ sweat collector, hydrated ion-conducting medium, electrode spacer, and mechanical buffer, collectively stabilizing the fiber–polymer interface under repeated bending. With Prussian blue embedded in the MIP network as an internal redox probe, the sensor enables label-free quantitative cortisol detection through steric-hindrance-mediated signal modulation, achieving a low limit of detection of 0.87 pM and a broad linear range from 1 pM to 10 μM. After integration into a wearable glove with a miniaturized wireless readout module, the platform tracks dynamic cortisol fluctuations during physical exercise and acute cold-pressor tests. This robust and ergonomically integrated platform provides a promising strategy for noninvasive endocrine monitoring and personalized stress assessment.