Enhanced localized plasmonic detections using partially-embedded gold nanoparticles and ellipsometric measurements

Area of Science:

• Nanotechnology
• Biosensing
• Optical Physics

Background:

• Localized surface plasmon resonance (LSPR) sensors offer high sensitivity for detecting molecular interactions.
• Existing LSPR sensors often face challenges with cost, stability, and fabrication complexity.

Purpose of the Study:

• To develop a cost-effective, stable, and ultrasensitive LSPR sensor.
• To enhance refractive index sensitivity and bio-molecular detection limits.
• To demonstrate the sensor's feasibility for biomedical applications.

Main Methods:

• Fabrication of partially embedded gold nanoparticles (AuNPs) on a transparent substrate via thermal annealing.
• Optical characterization using spectroscopic ellipsometry and theoretical modeling.
• Integration with a microfluidic flow cell and dove prism for enhanced LSPR signal detection.

Main Results:

• Achieved high refractive index sensitivity of up to 1938 degrees/RIU.
• Demonstrated a bio-molecular detection limit as low as 20 pM for antibody interactions.
• The sensor exhibits label-free, non-destructive, and stable performance.

Conclusions:

• The proposed partially embedded AuNPs LSPR sensor offers superior performance compared to colloidal nanoparticles.
• The sensor's high sensitivity, low cost, and ease of fabrication make it suitable for commercialization.
• This technology has significant potential for advancing biomedical diagnostics and research.