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.