Plasmonic nanobiosensor based on Au nanorods with improved sensitivity: A comparative study for two different...

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Analytical Chemistry

Background:

• Biosensors are crucial for sensitive biomolecule detection in disease diagnosis.
• There is a need for low-cost, fast, and reliable biosensors, especially for developing countries.
• Label-free plasmonic biosensors offer spectral tunability, real-time detection, and strong electric field enhancement.

Purpose of the Study:

• To develop and evaluate two configurations of localized surface plasmon resonance (LSPR) based biosensors using gold nanorods (AuNRs).
• To compare the sensitivity and figure of merit (FOM) of solution-phase AuNRs (S-P-AuNRs) and AuNRs-chip biosensors.
• To demonstrate the biosensors' capability for biomolecule detection through surface binding assays.

Main Methods:

• Developed two LSPR-based biosensor configurations: S-P-AuNRs and AuNRs-chip.
• Evaluated LSPR sensitivity by monitoring spectral shifts with changes in the surrounding medium's refractive index.
• Chemically modified AuNRs surfaces for antibody-antigen binding assays (anti-BSA).

Main Results:

• AuNRs-chip exhibited higher sensitivity (297 nm/RIU) compared to S-P-AuNRs (196 nm/RIU).
• AuNRs-chip achieved a higher FOM (3.0 RIU⁻¹) than S-P-AuNRs (2.2 RIU⁻¹).
• Both configurations showed efficient plasmonic sensing for refractive index changes and anti-BSA surface binding.

Conclusions:

• The AuNRs-chip configuration is a more sensitive and effective LSPR-based biosensor.
• The developed biosensors offer high sensitivity and potential for low-cost, rapid disease diagnosis.
• The study highlights the advantages of AuNRs-chip for advanced nanobiotechnology applications.