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Immunosensing platform based on gallium nanoparticle arrays on silicon substrates
Antonio García Marín1, María Jesús Hernández1, Eduardo Ruiz1
1Grupo de Electrónica y Semiconductores, Departamento de Física Aplicada, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
Biosensors & Bioelectronics
|August 16, 2015
Summary
Gallium nanoparticles on silicon substrates exhibit plasmonic effects useful for biosensing. Their optical properties change with surrounding medium, enabling sensitive detection of glutathione (GSH) at low concentrations.
Area of Science:
- Nanotechnology
- Plasmonics
- Biosensing
Background:
- Gallium nanoparticles (GaNPs) on Si(100) substrates exhibit plasmonic effects.
- Ellipsometry can probe these plasmonic resonances for biosensor development.
Purpose of the Study:
- To investigate the plasmonic properties of GaNPs for biosensing applications.
- To develop a GaNP/Si based immunosensor for glutathione detection.
Main Methods:
- Deposition of GaNPs on Si(100) via thermal evaporation.
- Ellipsometric analysis to study plasmonic effects and pseudodielectric function.
- Fourier transformed infrared spectroscopy (FTIR) for surface functionalization confirmation.
- Exposure of the immunosensor to varying glutathione (GSH) concentrations.
Main Results:
- Excitation of resonant modes in GaNPs leads to negative imaginary pseudodielectric function (<εi>).
- A reversal of polarization handedness (RPH) condition occurs at ~3.15 eV, sensitive to the surrounding medium.
- A linear relationship was observed between the slope of <εi> at RPH and GSH concentration.
Conclusions:
- The GaNP/Si system demonstrates potential as a sensitive sensor platform due to the optical response at the RPH condition.
- The developed immunosensor achieved a limit of detection of 10nM for glutathione.
- This technology can be applied for detecting low levels of GSH in various medical contexts.
