Wearable lateral flow assays for cortisol monitoring with time-dynamic sweat sampling and sensing by electrochromic timers
摘要
Cortisol is a key regulator of stress and circadian physiology, yet current monitoring relies on invasive blood sampling or saliva assays that are prone to contamination and provide limited temporal resolution. Wearable sweat cortisol sensors are promising, but require electronic sensing systems and have limited capability for long-term, time-sequenced monitoring. Here we present a wearable paper-based microfluidic platform that integrates plasmonic-gold-nanoflower-based colorimetric assays to enable non-invasive tracking of cortisol in eccrine sweat. Sweat is induced by carbachol iontophoresis and directed through collection channels using either electronically timed sequential activation or paper-based delay valves with self-powered electrochromic indicators. In human studies, the system resolved circadian variations, acute stress responses to cold pressor challenges, and jet-lag-associated disruptions, with the results closely matching those from saliva and serum assays. This wearable lateral flow technology establishes sweat as a viable medium for real-time hormone monitoring and may enable personalized management of stress, sleep and circadian misalignment.