Flexible electrochemical aptasensor for cortisol detection in human sweat

Area of Science:

• Biosensors
• Electrochemistry
• Materials Science

Background:

• Cortisol monitoring is crucial for assessing stress and health.
• Existing methods for cortisol detection can be invasive or complex.
• Developing wearable sensors for real-time cortisol analysis is highly desirable.

Purpose of the Study:

• To develop and validate a novel electrochemical DNA aptasensor for sensitive and selective cortisol detection.
• To fabricate a flexible and wearable sensor platform for analyzing cortisol in human sweat.
• To evaluate the performance characteristics of the aptasensor, including its dynamic range, precision, limit of detection, and selectivity.

Main Methods:

• Fabrication of a stretchable aptasensor using layer-by-layer assembly of cellulose nanocrystal/carbon nanotube (CNC/CNT) film on polydimethylsiloxane (PDMS).
• Immobilization of a cortisol-specific DNA aptamer onto the conductive film via a linker molecule.
• Electrochemical characterization and performance evaluation of the aptasensor for cortisol detection in artificial and human sweat samples.

Main Results:

• The flexible aptasensor exhibited a dynamic range of 2.5-35 ng mL⁻¹ for cortisol detection.
• Achieved a limit of detection (LOD) of approximately 1.8 ng mL⁻¹ with a precision of 2.7% relative standard deviation (%RSD).
• Demonstrated high selectivity towards cortisol, with no significant response to interfering substances like glucose, sodium lactate, and β-estradiol.

Conclusions:

• The developed electrochemical DNA aptasensor is a promising tool for sensitive, selective, and non-invasive cortisol monitoring in human sweat.
• The flexible and wearable nature of the aptasensor enables potential applications in continuous health and stress assessment.
• The successful detection of cortisol in actual sweat samples validates the aptasensor's practical utility.