Label-free plasmonic immunosensor for cortisol detection in a D-shaped optical fiber

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Optoelectronics

Background:

• Cortisol is a key stress biomarker linked to metabolic syndromes like anxiety and cardiovascular diseases.
• Fiber optic biosensors offer ultrasensitive cortisol detection, with ongoing advancements in accuracy and applications.
• Challenges remain in developing cost-effective, reproducible, and easily manufactured cortisol monitoring systems.

Purpose of the Study:

• To comprehensively characterize a D-shaped fiber optic immunosensor for cortisol detection using surface plasmon resonance (SPR).
• To detail the sensor's instrumentation, fabrication, and mathematical simulation.
• To evaluate the sensor's performance in experimental cortisol detection tests.

Main Methods:

• Fabrication and characterization of a gold-coated D-shaped fiber optic immunosensor.
• Surface Plasmon Resonance (SPR) principle for cortisol detection.
• Experimental validation of the sensor's performance across a defined detection range.
• Investigation of signal processing techniques for spectral data analysis.

Main Results:

• The D-shaped fiber optic immunosensor achieved a logarithmic sensitivity of 0.65 ± 0.02 nm/log(ng/mL).
• A limit of detection (LOD) of 1.46 ng/mL was attained for cortisol detection.
• The study detailed sensor fabrication, instrumentation, and simulation, alongside signal processing strategies.

Conclusions:

• The developed D-shaped fiber optic immunosensor shows promise for ultrasensitive cortisol monitoring.
• The sensor's design and characterization address key challenges in cortisol detection technology.
• Further optimization of signal processing is highlighted for enhanced data extraction from D-shaped sensors.