Flexible Dual-Channel Molecularly Imprinted Electrochemical Sensor for Simultaneously Monitoring Sweat Cortisol and Lactate Levels

While exercise offers significant potential to enhance overall well-being, unscientific exercise practices often cause exercise fatigue, posing a threat to human health. Flexible sweat sensors have garnered considerable attention owing to their ability to continuously, non-invasively, and dynamically monitor human health during exercise at the molecular level. Therefore, in this study, we constructed a flexible molecularly imprinted polymer (MIP) sensor for the real-time monitoring of cortisol and lactate levels in sweat using cortisol or lactate as template molecules and pyrrole (Py) as functional monomer. Prussian blue (PB) was embedded into the MIP as a built-in redox probe, eliminating the need for an additional probe and facilitating the simultaneous quantification of cortisol and lactate concentrations. Moreover, the MIP-doped platinum nanoparticles (PtNPs) ehanced the electron transfer capability, further improving the sensitivity of the sensors. The fabricated flexibile cortisol and lactate MIP sensors demonstrated low limits of detection (LOD; 1.07 nM and 1.09 mM, respectively), high sensitivity (0.09 μA lg[nM]⁻¹ and 1.28 μA lg[nM]⁻¹), and exceptional stability and selectivity. The flexible MIP sensors could continuously and dynamically monitor changes in sweat cortisol and lactate concentrations, thus contributing to the advancement of next-generation flexible sweat electrochemical sensors and providing a crucial tool for monitoring exercise fatigue.