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Compact plasmonic optical biosensors based on nanostructured gradient index lenses integrated into microfluidic cells
A Horrer1, J Haas, K Freudenberger
1Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany. andreas.horrer@uni-tuebingen.de monika.fleischer@uni-tuebingen.de.
Nanoscale
|November 3, 2017
Summary
This study presents a compact, cost-effective biosensor using gold nanostructures and localized surface plasmon resonance (LSPR). The novel design achieves high sensitivity for label-free detection, demonstrated with a testosterone immunoassay.
Area of Science:
- Nanotechnology
- Biomedical Engineering
- Optics
Background:
- Label-free biosensors are crucial for real-time analyte detection.
- Localized Surface Plasmon Resonance (LSPR) offers high sensitivity for refractive index changes.
- Miniaturization and integration are key challenges in current biosensor technology.
Purpose of the Study:
- To develop a compact and cost-effective integrated biosensor.
- To leverage LSPR sensitivity of gold nanostructures for label-free detection.
- To demonstrate the biosensing capabilities of the novel configuration.
Main Methods:
- Fabrication of gold nanodiscs on a gradient index (GRIN) lens.
- Integration of the GRIN lens into a microfluidic flow cell.
- Spatially and spectrally resolved investigation of scattered light from nanostructures.
- Dynamic spectral analysis of LSPR shifts during refractive index changes.
Main Results:
- Achieved high refractive index sensitivity up to 372 nm/RIU.
- Demonstrated label-free detection of analyte binding.
- Successfully performed a testosterone immunoassay.
Conclusions:
- The integrated GRIN lens-based LSPR biosensor is compact, cost-effective, and highly sensitive.
- This configuration enables efficient label-free detection of biomolecular interactions.
- The developed biosensor shows significant potential for various diagnostic applications.
