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Molecularly imprinted polymer wearable biosensing of cortisol in sweat for mental stress evaluation
Chaobo Dai1, Zijian An2, Fengrong Liu2
1Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, PR China; Taizhou Key Laboratory of Medical Devices and Advanced Materials, Zhejiang Key Laboratory of Intelligent Medical Decision Support, Taizhou Institute of Zhejiang University, 318000, PR China; Binjiang Institute of Zhejiang University, Hangzhou, 310053, PR China.
Insights
We developed a novel electrochemical sensor for non-invasive cortisol detection in sweat. This system offers accurate stress monitoring and potential for personalized health protection.
Area of Science:
- Electrochemistry
- Materials Science
- Biomedical Engineering
Background:
- Cortisol detection is vital for diagnosing adrenal disorders and managing stress.
- Current methods (serum tests, immunosensors) are invasive, complex, and costly.
- A need exists for accessible, non-invasive cortisol monitoring.
Purpose of the Study:
- To develop a molecularly imprinted polymer (MIP)-based electrochemical sensor for label-free cortisol detection in sweat.
- To create a flexible, wireless system for real-time, non-invasive stress tracking.
Main Methods:
- Fabrication of a polypyrrole-based MIP incorporating Prussian Blue (PB) as a redox probe.
- Optimization of MIP parameters (template, monomer, modification time, excitation current).
- Integration of the MIP sensor with a flexible electrode for wireless data transmission via smartphone.
Main Results:
- The MIP sensor demonstrated selective cortisol recognition with an imprinting factor (IF) of 7.7.
- Achieved high sensitivity with a wide linear range (50-500 ng/mL), low LOD (15.21 ng/mL), and LOQ (46.09 ng/mL).
- Real-time sweat analysis correlated well with gold standard methods, validating accuracy in stress-inducing scenarios.
Conclusions:
- The developed MIP electrochemical sensor provides a sensitive and accurate platform for non-invasive cortisol monitoring.
- This novel sensing system enables real-time stress tracking and personalized health protection.
- The technology holds significant potential for advancing precision health and stress management strategies.
Abstract:
Accurate detection of cortisol levels is crucial for stress management and the diagnosis of hypothalamic-pituitary-adrenal axis disorders. Current methods rely on invasive serum tests or immunosensors with complex procedures and are expensive. Here, we developed a molecularly imprinted polymer (MIP)-based electrochemical sensing system for label-free detection of cortisol in sweat, in which polypyrrole exhibited selective recognition of cortisol via hydrogen bonding, and prussian blue (PB) was embedded into the MIP as the redox probe. By optimizing parameters including the template, monomer, modification time, and excitation current, the MIP exhibited strong affinity for cortisol with an imprinting factor (IF) value of 7.7. The MIP sensors' sensitivity is also significantly enhanced, showing a wide linear range from 50 to 500 ng/mL, with the LOD and LOQ at 15.21 ng/mL and 46.09 ng/mL. The fully integrated system employs a flexible electrode for real-time cortisol analysis and enables wireless data transmission via circuitry and smartphones. Human sweat analysis was conducted in scenarios involving circadian rhythms and ice-water stimulation. The results were consistent with literature findings and validated the sensor's high accuracy compared to the gold standard measurement method. The proposed novel MIP sensing platform opened compelling possibilities for non-invasive stress tracking, offering significant potential for personalized stress prevention to achieve precision health protection.
