A reflection-based localized surface plasmon resonance fiber-optic probe for biochemical sensing

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Spectroscopy

Background:

• Localized Surface Plasmon Resonance (LSPR) offers unique optical properties for biosensing.
• Optical fiber probes provide a versatile platform for remote and in-situ measurements.
• Developing sensitive and label-free biosensors is crucial for early disease detection and diagnostics.

Purpose of the Study:

• To fabricate and characterize an optical fiber biochemical sensing probe utilizing LSPR.
• To experimentally validate the theoretical prediction of LSPR scattering and extinction spectral shifts.
• To demonstrate the sensor's capability for label-free detection of biomolecules.

Main Methods:

• Fabrication of ordered gold nanodot arrays on an optical fiber end facet using electron-beam lithography (EBL).
• Characterization of the optical fiber probe using LSPR and spectral reflection.
• Experimental demonstration of LSPR scattering and extinction spectral shifts.
• Assessment of sensor sensitivity to bulk refractive index changes.
• Demonstration of label-free affinity sensing using biotin-streptavidin interactions.

Main Results:

• Successful fabrication of gold nanodots on an optical fiber end facet via EBL.
• Experimental confirmation of the blue shift in LSPR scattering spectrum relative to the LSPR extinction spectrum.
• Achieved high sensitivity of 195.72 nm/RIU for detecting refractive index variations.
• Demonstrated label-free affinity sensing of biomolecules (biotin-streptavidin).

Conclusions:

• The developed optical fiber LSPR probe is a sensitive platform for biochemical sensing.
• The sensor exhibits high sensitivity to refractive index changes and label-free biomolecule detection.
• This technology holds potential for various diagnostic and analytical applications.