Enhanced photostability of ICG in close proximity to gold colloids

Geddes, Chris D.; Cao, Haishi; Lakowicz, Joseph R.

doi:10.1016/s1386-1425(03)00015-5

Cited by 42 publications

(42 citation statements)

References 31 publications

(38 reference statements)

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“…Silver nanostructures, used in recent studies for metal-enhanced fluorescence, 13,14,[17][18][19][20][21][22][23][24][25][26]29,34 show blinking that is dependent on both the type of structure studied and irradiance of the illumination source. We typically observed that silver fractal-like structures could readily be made luminescent with irradiances of 30 W/cm 2 or more, as compared to silver island films, which required at least a 3-5-fold increase, >100 W/cm 2 .…”

Section: Discussionmentioning

confidence: 99%

“…In addition to studying their luminescent blinking properties for potential applications as luminescent probes, as markers, and for medical imaging, our primary interest lies in their interactions with organic fluorophores, and how they modify fluorophore spectral properties. The favorable effects produced by close proximity fluorophores to metallic nanostructures includes increased quantum yields and reduced lifetimes, 13,14,17,18 increased fluorophore photostability, 13,14,19,20 enhanced multiphoton excitation, 21,22 and modified rates of energy transfer. [23][24][25] These interactions have been described as due to changes in the photonic mode density, PMD, around the fluorophore,26 and are considered to be through-space as compared to SERS, which is widely thought to be a contact interaction.27 , 28 Such effects are not normally observed in bulk media, where the photonic mode density is not that different from a vacuum, but can be changed by close proximity silver nanostructures.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Luminescent Blinking from Silver Nanostructures.

Geddes¹,

Parfenov²,

Gryczyński³

et al. 2003

ChemInform

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Silver nanostructures deposited on glass showed luminescent blinking when excited at a high 442 nm irradiance. The irradiance required to photoactivate the silver, was dependent on the nature of the silver nanostructures. Silver fractal-like structures were found to be highly emissive, requiring only ≈30 W/cm 2 for photoactivation as compared to silver island films and spin-coated silver colloids, which required a significantly higher irradiance, > 100 W/cm 2 , to observe similar luminescent emission. In contrast to our recent findings for gold colloids, foci with different color blinking were also observed, with an increase in luminescence intensity as a function of time. We place these findings in context with recent work from our laboratory which employs these silver nanostructures for applications in metal-enhanced fluorescence, a relatively new phenomenon in fluorescence, whereby metallic particles, colloids, and fractal-like structures can modify the intrinsic radiative decay rate of close proximity fluorescent species. These effects are a consequence of localized changes in photonic mode density around the fluorophores, and we can now report are typically observed at significantly lower illumination intensities as compared to those required to photoactivate silver. Subsequently, our findings strongly suggest that the enhanced fluorescence emission of fluorophores positioned in close proximity to metallic silver structures is not due to either intrinsic silver blinking, or indeed the silver luminescence pumping the fluorophore. Further, the intrinsic luminescence properties of silver reported here, suggest a new class of luminescence probes and labels.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Luminescent Blinking from Silver Nanostructures.

Geddes¹,

Parfenov²,

Gryczyński³

et al. 2003

ChemInform

View full text Add to dashboard Cite

show abstract

“…These effects are due to the interactions of the excited-state fluorophores with the surface plasmon resonances on the surface of the metal [14][15][16][17]. These interactions can result in increased rates of excitation, increased intensities (quantum yields), and even quenching [18]. For our applications of enhanced fluorescence/luminescence and therefore luminophore detectability, the most important effect is an increase in the radiative decay rate of fluorophores, , which occurs for fluorophores positioned ≈50-200Å from the metallic surface [14,17].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Lanthanide Luminescence Using Silver Nanostructures: Opportunities for a New Class of Probes with Exceptional Spectral Characteristics

Lakowicz

Geddes

2005

J Fluoresc

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The photophysical effects of europium tetracycline immobilized in thin polyvinyl alcohol films coated onto silver nanostructures have been investigated. Complimentary to recent reports from our laboratories that the close proximity of luorophores to silver nanostructures can enhance their intrinsic radiative decay rate, we show that up to a 16-fold enhancement in lanthanide luminescence is possible, accompanied by a notable reduction in luminescence lifetime. These results suggest the potential future development of a new class of significantly brighter lanthanide based probes with exceptional spectral properties, which can probably undergo significantly more excitation-emission event cycles due to the reduced lifetime, substantially increasing detectability.

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“…In this short note, we show that 3-to 5-fold enhanced fluorescence signals can be obtained from SiO 2 -coated silver colloids labeled with Cy3 and by their aggregation in suspension. This inert coating alleviates the close proximity quenching by noble-metals [1,9], as well as provides for a wide variety of chemistries for biomolecule attachment.The preparation of silica-coated silver spheres and biotinylation of the silica coated silver spheres in suspension is performed in multiple steps. Firstly, the silver spheres were prepared in solution.…”

mentioning

confidence: 99%

“…This inert coating alleviates the close proximity quenching by noble-metals [1,9], as well as provides for a wide variety of chemistries for biomolecule attachment.…”

mentioning

confidence: 99%

Metal Enhanced Fluorescence Solution-based Sensing Platform 2: Fluorescent Core-Shell Ag@SiO2 Nanoballs

Aslan

Lakowicz

et al. 2007

J Fluoresc

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In recent years our laboratories have reported the favorable effects for fluorophores placed in close proximity to surface immobilized silver nanostructures. These include; greater quantum yields, reduced lifetimes (increased photostability) and directional emission. However, while these findings are likely to find multifarious applications for surface assays based on enhanced fluorescence detection, a solution based enhanced sensing platform has yet to be realized. In this short, note, we show how SiO 2 -coated silver colloids, indeed provide for a solution based enhanced fluorescence sensing platform with a 3-5 fold enhancement typically observed. KEY WORDS:Radiative decay engineering; metal-enhanced fluorescence; solution assays.Recently our laboratories have fabricated numerous noble-metal surfaces for metal-enhanced fluorescence detection whereby fluorophores can undergo modifications in their radiative decay rate, , Fig. 1 [1 -8]. Silver island films (SiFs), formed an APS-coated glass slides by the reduction of silver nitrate by glucose, have proved a versatile surface, providing up-to 10 fold increases in fluorescence signal of appropriate fluorophores [1][2][3][4][5]. Silver colloid coated surfaces have yielded up-to 50-fold enhancements [6], while silver-fractal-like coatings have been shown to increase fluorescein emission, several thousand fold [7,8]. These findings have been most encouraging and suggest the use of metallic nanostructures in surface assays and high-throughput screening plate-well formats. However, to date, little attention has been given to solution-based systems. This is in part due to the complexities associated with working with nano-or picomolar concentrations of 4 To whom correspondence should be addressed. E-mail: geddes@umbi.umd.edu silver colloids, their purification, and comparison with an appropriate control system, i.e. a sample with no silver. In this short note, we show that 3-to 5-fold enhanced fluorescence signals can be obtained from SiO 2 -coated silver colloids labeled with Cy3 and by their aggregation in suspension. This inert coating alleviates the close proximity quenching by noble-metals [1,9], as well as provides for a wide variety of chemistries for biomolecule attachment.The preparation of silica-coated silver spheres and biotinylation of the silica coated silver spheres in suspension is performed in multiple steps. Firstly, the silver spheres were prepared in solution. In this regard, 2 mL of 1.16 mM trisodium citrate solution was added drop wise to a heated (95• C) aqueous solution of 0.65 mM of AgNO 3 while stirring. The mixture was kept heated for 10 min, and then it was cooled to room temperature. This procedure yields silver spheres with sizes in the range of 30 to 80 nm. The surface of the silver spheres were modified with 3-(aminopropyl)ethoxysilane (APS) in ethanol. The APS-coated silver spheres were resuspended in a predetermined amount of water and NH 4 OH. Then, a solution of ABBREVIATIONS: TEOS, tetraethylorthosilicate; BSA, bovine serum albumin;...

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Enhanced photostability of ICG in close proximity to gold colloids

Cited by 42 publications

References 31 publications

Luminescent Blinking from Silver Nanostructures.

Luminescent Blinking from Silver Nanostructures.

Enhanced Lanthanide Luminescence Using Silver Nanostructures: Opportunities for a New Class of Probes with Exceptional Spectral Characteristics

Metal Enhanced Fluorescence Solution-based Sensing Platform 2: Fluorescent Core-Shell Ag@SiO2 Nanoballs

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