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Evaluating Plasmonic Transport in Current-carrying Silver Nanowires
Published on: December 11, 2013
Localized surface plasmon resonance biosensor using silver nanostructures fabricated by glancing angle deposition.
Douglas A Gish1, Francis Nsiah, Mark T McDermott
1Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada. dgish@ualberta.ca
Analytical Chemistry
|May 5, 2007
Summary
Silver nanoparticle films function as localized surface plasmon resonance (LSPR) biosensors. These LSPR biosensors detect specific biomolecular binding events by measuring shifts in light extinction peaks.
Area of Science:
- Nanotechnology
- Biophysics
- Materials Science
Background:
- Localized surface plasmon resonance (LSPR) in metallic nanoparticles offers sensitive detection capabilities.
- Silver nanoparticle (AgNP) films exhibit strong optical properties exploitable for biosensing applications.
- Functionalization of AgNP surfaces is crucial for specific biomolecule recognition.
Purpose of the Study:
- To evaluate silver nanoparticle films as localized surface plasmon resonance (LSPR) biosensors.
- To investigate the optical response of AgNP films to changes in environmental refractive index.
- To quantify the binding kinetics of anti-rabbit immunoglobulin G (anti-rIgG) to functionalized AgNP surfaces.
Main Methods:
- Fabrication of ~150-nm-thick silver nanoparticle films using glancing angle deposition.
- Characterization of LSPR extinction peaks and their dependence on the surrounding refractive index.
- Functionalization of AgNP surfaces with 11-amino-1-undecanethiol and rabbit immunoglobulin G (rIgG).
- Measurement of wavelength shifts in response to varying concentrations of anti-rIgG and fitting to the Langmuir isotherm.
Main Results:
- AgNP films exhibited a strong extinction peak around 368 nm in air due to LSPR.
- A linear red-shift of the extinction peak was observed with increasing refractive index.
- Specific binding of anti-rIgG resulted in a measurable red-shift, enabling quantification.
- Langmuir isotherm fitting yielded a saturation response (Delta lambda max) of 29.4 +/- 0.7 nm and a binding constant (Ka) of (2.7 +/- 0.3) x 10^6 M^-1.
- Nonspecific binding effects were also assessed.
Conclusions:
- Glancing angle deposited silver nanoparticle films are effective LSPR biosensors.
- The red-shift of the LSPR extinction peak provides a sensitive measure of biomolecular binding.
- The developed biosensor demonstrates quantifiable detection of specific antibody-antigen interactions with determined binding kinetics.
