The Localized Enhancement of Surface Plasmon Standing Waves Interacting With Single Nanoparticles

Abstract Real-time, high-sensitivity, and label-free detection to single nanoparticles has been achieved via visualizing the interaction between surface plasmon polaritons (SPPs) and nanoparticles, which is widely applied to chemistry and biology. In this work, aiming to enhance the detection sensitivity to nanoparticles, we explore the interaction of SPP standing waves with single nanoparticles. Compared with SPPs, the inhomogeneous fields of SPP standing waves modulate charge distributions around the particle and excite different electric dipole modes that tailor localized enhancements. For nanoparticles situating at electric antinodes of SPP standing waves, a vertical electric dipole is excited and high-density charges are stimulated around nanoparticle-film nanocavities, leading to further increased localized enhancement. The localized enhancement experiences more increase with smaller particle size, lower dielectric constant of surrounding medium, and lower particle refractive index. Via tailoring the localized enhancement by SPP standing waves, the sensitivity of SPP microscopy can be improved, which would broaden its applications on nanotechnology, biomedicine, and environmental monitoring.

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A sandwich-like strategy for the label-free detection of oligonucleotides by surface plasmon fluorescence spectroscopy (SPFS)

The Analyst ◽

10.1039/c6an01129b ◽

2016 ◽

Vol 141 (20) ◽

pp. 5784-5791 ◽

Cited By ~ 4

Author(s):

Qiang Su ◽

Gilbert Nöll

Keyword(s):

Fluorescence Spectroscopy ◽

Surface Plasmon ◽

Molecular Beacons ◽

Label Free ◽

Background Fluorescence ◽

Detection Strategy ◽

Cutting Surface ◽

Label Free Detection ◽

Lower Background

Cutting surface-bound optical molecular beacons results in a sandwich-like detection strategy with lower background fluorescence.

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Trends in SPR Cytometry: Advances in Label-Free Detection of Cell Parameters

Biosensors ◽

10.3390/bios8040102 ◽

2018 ◽

Vol 8 (4) ◽

pp. 102 ◽

Cited By ~ 8

Author(s):

Richard Schasfoort ◽

Fikri Abali ◽

Ivan Stojanovic ◽

Gestur Vidarsson ◽

Leon Terstappen

Keyword(s):

Surface Plasmon Resonance ◽

Surface Plasmon ◽

Plasmon Resonance ◽

Mammalian Cells ◽

Living Cells ◽

Label Free ◽

Intact Cells ◽

Cell Parameters ◽

Spr Imaging ◽

Label Free Detection

SPR cytometry entails the measurement of parameters from intact cells using the surface plasmon resonance (SPR) phenomenon. Specific real-time and label-free binding of living cells to sensor surfaces has been made possible through the availability of SPR imaging (SPRi) instruments and researchers have started to explore its potential in the last decade. Here we will discuss the mechanisms of detection and additionally describe the problems and issues of mammalian cells in SPR biosensing, both from our own experience and with information from the literature. Finally, we build on the knowledge and applications that has already materialized in this field to give a forecast of some exciting applications for SPRi cytometry.

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Photonic crystals: A platform for label-free and enhanced fluorescence biomolecular and cellular assays

MRS Proceedings ◽

10.1557/proc-1133-aa04-01 ◽

2008 ◽

Vol 1133 ◽

Author(s):

Brian T. Cunningham ◽

Leo Chan ◽

Patrick C. Mathias ◽

Nikhil Ganesh ◽

Sherine George ◽

...

Keyword(s):

Photonic Crystal ◽

Photonic Crystals ◽

High Throughput Screening ◽

High Sensitivity ◽

Excitation Wavelength ◽

Label Free ◽

Crystal Surfaces ◽

Enhanced Fluorescence ◽

Preferred Direction ◽

Label Free Detection

Abstract Photonic crystal surfaces represent a class of resonant optical structures that are capable of supporting high intensity electromagnetic standing waves with near-field and far-field properties that can be exploited for high sensitivity detection of biomolecules and cells. While modulation of the resonant wavelength of a photonic crystal by the dielectric permittivity of adsorbed biomaterials enables label-free detection, the resonance can also be tuned to coincide with the excitation wavelength of common fluorescent tags - including organic molecules and semiconductor quantum dots. Photonic crystals are also capable of efficiently channeling fluorescent emission into a preferred direction for enhanced extraction efficiency. Photonic crystals can be designed to support multiple resonant modes that can perform label free detection, enhanced fluorescence excitation, and enhanced fluorescence extraction simultaneously on the same device. Because photonic crystal surfaces may be inexpensively produced over large surface areas by nanoreplica molding processes, they can be incorporated into disposable labware for applications such as pharmaceutical high throughput screening. In this talk, the optical properties of surface photonic crystals will be reviewed and several applications will be described, including results from screening a 200,000-member chemical compound library for inhibitors of protein-DNA interactions, gene expression microarrays, and high sensitivity of protein biomarkers.

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