Enhancement and Quenching of Single-Molecule Fluorescence

Anger, Pascal; Bharadwaj, Palash; Novotny, Lukas

doi:10.1103/physrevlett.96.113002

Cited by 2,882 publications

(3,191 citation statements)

References 27 publications

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“…As discussed above, by linking the dyes to the AuNRs surface with the biotin/streptavidin conjugation, they are kept at an average distance of 5 nm from the metal, thus, avoiding the quenching of the plasmonicfluorescent nanoprobes. 30,31 At this distance, the still-appreciable field enhancement produced by the AuNR (see Figure 2 To demonstrate the potential of the AuNRs for NP-STED, we functionalized a glass cover-slip to attach the AuNRs to the surface (see Methods for further details) and compared the resolution improvement relative to confocal microscopy for the AuNR and for 20 nm diameter crimson red beads as a function of the power of the depletion-beam. Assuming that the depletion beam pulse length, , is much smaller than the fluorescence lifetime of the fluorophore, 1 , the resolution achievable with pulsed STED depends on the wavelength, λ, the numerical aperture (NA) of the objective, the peak intensity of the depletion beam, , and the saturation intensity of the fluorophore, , as given by: 16,32 Hence, we can write the STED resolution improvement with respect to confocal microscopy as Γ = √1 + ∅.…”

Section: Green (Blue) Line Is the Absorption (Emission) Spectrum Of Tmentioning

confidence: 99%

Plasmonic Nanoprobes for Stimulated Emission Depletion Nanoscopy

Cortés¹,

Huidobro²,

Sinclair³

et al. 2016

ACS Nano

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Plasmonic nanoparticles influence the absorption and emission processes of nearby emitters due to local enhancements of the illuminating radiation and the photonic density of states. Here, we use the plasmon resonance of metal nanoparticles in order to enhance the stimulated depletion of excited molecules for super-resolved nanoscopy. We demonstrate stimulated emission depletion (STED) nanoscopy with gold nanorods with a long axis of only 26 nm and a width of 8 nm that provide an enhancement of up to 50% of the resolution compared to fluorescent-only probes without plasmonic components irradiated with the same depletion power. The nanoparticle-assisted STED probes reported here represent a ~2x10 3 reduction in probe volume compared to previously used nanoparticles. Finally, we demonstrate their application toward plasmon-assisted STED cellular imaging at low-depletion powers and we also discuss their current limitations. Key-words: STED nanoscopy, nanorods, super-resolution, plasmonic nanoparticles, bio-imagingThe diffraction limit has ceased to be a practical limit to resolution in far-field microscopy, following the demonstration of STED, 1,2,3 RESOLFT 4 and localisation microscopies 5,6,7 and the subsequent development of a plethora of super-resolved nanoscopy techniques. 8 In particular, stimulated emission depletion (STED) nanoscopy, which builds on the advantages of laser scanning confocal microscopy, is a powerful technique for super-resolved imaging in complex biological samples including live organisms. 9,10 STED nanoscopy uses stimulated emission to turn off the spontaneous fluorescence emission of dye molecules, typically overlapping a focused excitation beam with a "doughnut" shaped beam that deexcites emitters to the ground state everywhere except for the area within the centre of the doughnut, thus providing theoretically diffraction-unlimited resolution in the transverse plane by reducing the fullwidth half-maximum (FWHM) of the point spread function. By increasing the power of the depletion beam the emission region can be can be drastically reduced -theoretically allowing for sub-nanometre resolution -with resolutions of less than 10 nm being demonstrated. 11 The scaling of resolution with the square root of the depletion beam power means that relatively high-power lasers are typically used for STED nanoscopy. In practice, however, the use of high-power irradiation can result in problems such as photobleaching of the fluorophores and phototoxicity, and so the achievable resolution is compromised by the need to limit the intensity of the depletion laser radiation. Furthermore, high power lasers can add cost and complexity to STED microscopes and so the requirement for high power depletion beams presents challenges for parallelizing STED measurements 12,13 in terms of the lasers required, thus, limiting the potential for faster super-resolved imaging.To some extent the issue of photobleaching can be addressed with the development of more robust fluorescent labels such as quantum dots 14 as ...

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Section: Green (Blue) Line Is the Absorption (Emission) Spectrum Of Tmentioning

confidence: 99%

Plasmonic Nanoprobes for Stimulated Emission Depletion Nanoscopy

Cortés¹,

Huidobro²,

Sinclair³

et al. 2016

ACS Nano

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“…5,6 The near-field of the plasmonic structure can modify the emission of a fluorophore. [7][8][9][10][11][12] Depending on the plasmonic properties of the metallic nanoparticle (MNP) it can lead to quenching or enhancement of the fluorophore emission. The modified emission can be a consequence of many processes such as NRET to the MNP, scattering and absorption by the MNP, and changes in the emitter's radiative and nonradiative decay rates.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Theoretical Investigation of the Distance Dependence of Localized Surface Plasmon Coupled Förster Resonance Energy Transfer

et al. 2014

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The distance dependence of localized surface plasmon (LSP) coupled Förster resonance energy transfer (FRET) is experimentally and theoretically investigated using a trilayer structure composed of separated monolayers of donor and acceptor quantum dots with an intermediate Au nanoparticle layer. The dependence of the energy transfer efficiency, rate, and characteristic distance, as well as the enhancement of the acceptor emission, on the separations between the three constituent layers is examined. A d –4 dependence of the energy transfer rate is observed for LSP-coupled FRET between the donor and acceptor planes with the increased energy transfer range described by an enhanced Förster radius. The conventional FRET rate also follows a d –4 dependence in this geometry. The conditions under which this distance dependence is valid for LSP-coupled FRET are theoretically investigated. The influence of the placement of the intermediate Au NP is investigated, and it is shown that donor–plasmon coupling has a greater influence on the characteristic energy transfer range in this LSP-coupled FRET system. The LSP-enhanced Förster radius is dependent on the Au nanoparticle concentration. The potential to tune the characteristic energy transfer distance has implications for applications in nanophotonic devices or sensors.

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“…12, 13 Fluorescence enhancement by plasmonic nanoparticles has been studied extensively over the past few decades. Early reports by the groups of Sandoghdar 14 and Novotny 15 employed a single gold nanosphere of 80 nm in diameter and achieved a fluorescence enhancement of a factor of 9. The fluorescence enhancement near gold nanospheres is modest because of the relatively small field enhancement (∼5 times).…”

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confidence: 99%

Resonant Plasmonic Enhancement of Single-Molecule Fluorescence by Individual Gold Nanorods

et al. 2014

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Enhancing the fluorescence of a weak emitter is important to further extend the reach of single-molecule fluorescence imaging to many unexplored systems. Here we study fluorescence enhancement by isolated gold nanorods and explore the role of the surface plasmon resonance (SPR) on the observed enhancements. Gold nanorods can be cheaply synthesized in large volumes, yet we find similar fluorescence enhancements as literature reports on lithographically fabricated nanoparticle assemblies. The fluorescence of a weak emitter, crystal violet, can be enhanced more than 1000-fold by a single nanorod with its SPR at 629 nm excited at 633 nm. This strong enhancement results from both an excitation rate enhancement of ∼130 and an effective emission enhancement of ∼9. The fluorescence enhancement, however, decreases sharply when the SPR wavelength moves away from the excitation laser wavelength or when the SPR has only a partial overlap with the emission spectrum of the fluorophore. The reported measurements of fluorescence enhancement by 11 nanorods with varying SPR wavelengths are consistent with numerical simulations.

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Enhancement and Quenching of Single-Molecule Fluorescence

Cited by 2,882 publications

References 27 publications

Plasmonic Nanoprobes for Stimulated Emission Depletion Nanoscopy

Plasmonic Nanoprobes for Stimulated Emission Depletion Nanoscopy

Experimental and Theoretical Investigation of the Distance Dependence of Localized Surface Plasmon Coupled Förster Resonance Energy Transfer

Resonant Plasmonic Enhancement of Single-Molecule Fluorescence by Individual Gold Nanorods

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