Development of ultra-low volume, multi-bio fluid, cortisol sensing platform

Area of Science:

• Electrochemistry
• Biosensors
• Analytical Chemistry

Background:

• Cortisol monitoring is crucial for diagnosing various health conditions.
• Existing methods for cortisol detection can be complex and require large sample volumes.
• There is a need for rapid, sensitive, and versatile cortisol screening tools.

Purpose of the Study:

• To develop and validate a non-faradaic electrochemical sensor for cortisol detection.
• To enable multi-bio-fluid screening using minimal sample volumes.
• To enhance sensor performance through optimized design and material selection.

Main Methods:

• Fabrication of a gold microelectrode-based electrochemical sensor.
• Utilized room temperature ionic liquid (RTIL), BMIM[BF4], to modulate the electrical double layer (EDL).
• Optimized sensor design via COMSOL Multiphysics simulations and surface chemistry using FTIR.
• Employed non-faradaic Electrochemical Impedance Spectroscopy (EIS) for cortisol detection.

Main Results:

• The sensor successfully detected cortisol in serum, blood, sweat, and saliva within physiologically relevant ranges.
• Achieved high specificity for cortisol, with minimal cross-reactivity observed for prednisone.
• Demonstrated excellent correlation (R² > 0.95) between sensor response and cortisol concentration.
• Established dynamic ranges for cortisol detection across different bio-fluids (e.g., 50-200 ng/mL in serum/blood).

Conclusions:

• The developed non-faradaic electrochemical sensor offers a sensitive and specific platform for multi-bio-fluid cortisol screening.
• The use of RTIL and optimized design enables ultra-low volume detection, enhancing practicality.
• This sensor shows significant potential for point-of-care applications in diagnostics and health monitoring.