Aptamer-Based Lateral Flow Biosensor for Rapid Detection of Salivary Cortisol

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Molecular Diagnostics

Background:

• Saliva offers a noninvasive alternative to blood for biomarker monitoring.
• Aptamers provide specific and stable recognition elements for biosensors.
• Point-of-care (POC) devices enable rapid diagnostics outside traditional lab settings.

Purpose of the Study:

• To develop a disposable aptamer-based biosensor for salivary cortisol detection.
• To establish a noninvasive and rapid method for stress biomarker monitoring.

Main Methods:

• Utilized a lateral flow assay (LFA) device with aptamer-conjugated gold nanoparticles (AuNPs).
• Employed Au-S bonds for stable conjugation of aptamers to AuNPs.
• Analyzed cortisol-induced conformational changes in aptamers leading to signal generation.

Main Results:

• The biosensor accurately detects salivary cortisol in the range of 0.5-15 ng/mL.
• Achieved a limit of detection of 0.37 ng/mL with high selectivity.
• Results were validated against enzyme-linked immunosorbent assay (ELISA) for accuracy.

Conclusions:

• Developed a simple, fast, and accurate POC aptasensor for salivary cortisol.
• Demonstrated the potential of aptamer-based LFAs for noninvasive stress biomarker monitoring.
• The sensor exhibits high specificity against related steroids and biomarkers.