Hybridization of localized surface plasmon resonance-based Au-Ag nanoparticles

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Engineering

Background:

• Silver nanoparticles are prone to oxidation, limiting their use in biosensing.
• Gold nanoparticles offer stability but may lack the desired sensitivity for certain applications.

Purpose of the Study:

• To develop stable and sensitive hybrid gold-silver (Au-Ag) triangular nanoparticles for enhanced biomolecule detection.
• To investigate the optical properties and localized surface plasmon resonance (LSPR) of Au-Ag nanoparticles.
• To demonstrate the practical application of Au-Ag nanoparticles in biosensing.

Main Methods:

• Fabrication of hybrid Au-Ag triangular nanoparticles by depositing a gold (Au) thin film onto silver (Ag) nanoparticles on a glass substrate.
• Computational design and simulation using the finite-difference time-domain (FDTD) algorithm.
• Calculation of extinction spectra and electric field distributions.
• Experimental validation through refractive index sensitivity measurements and biomolecule detection using Protein A.

Main Results:

• The gold protective layer effectively prevented silver oxidation, enhancing nanoparticle stability.
• Calculated and experimental extinction spectra confirmed the excitation of localized surface plasmon resonance (LSPR).
• High refractive index sensitivity was achieved, demonstrating the potential for sensitive biomolecule detection.
• Successful detection of biomolecules using Protein A-functionalized Au-Ag nanoparticles was achieved.

Conclusions:

• Hybrid Au-Ag triangular nanoparticles provide a stable and sensitive platform for biosensing.
• The LSPR properties of these nanoparticles are crucial for their detection capabilities.
• Both computational modeling and experimental results validate the utility of Au-Ag nanoparticles in biomolecule detection.