SERS as a Foundation for Nanoscale, Optically Detected Biological Labels

Doering, William E.; Piotti, Marcelo E.; Natan, Michael J.; Freeman, Ronit

doi:10.1002/adma.200701984

Cited by 347 publications

(274 citation statements)

References 51 publications

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“…In the calculations the field enhancement refers to (E/E in ) 2 with E in being the incident field and is evaluated at ϭ 403 nm, which is the LSP resonance of Ag nanosphere. In view of the underlying simplification of the model, it is justified to assume that the SERS EF could be approximated to be (E/E in ) 4 . In Figure 4, the SERS enhancement factor (E/E in ) 4 is plotted as a function of the distance from the sphere center (Z ϭ 0) and 10 nm (Z ϭ 10 nm) and 20 nm (Z ϭ 20 nm) from the center of the Ag sphere.…”

Section: Resultsmentioning

confidence: 99%

Ultrathin Diamond-like Carbon Film Coated Silver Nanoparticles-Based Substrates for Surface-Enhanced Raman Spectroscopy

et al. 2010

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We have demonstrated that by coating with a thin dielectric layer of tetrahedral amorphous carbon (ta-C), a biocompatible and optical transparent material in the visible range, the Ag nanoparticle-based substrate becomes extremely suitable for surface-enhanced Raman spectroscopy (SERS). Our measurements show that a 10 Å or thicker ta-C layer becomes efficient to protect the oxygen-free Ag in air and prevent Ag ionizing in aqueous solutions. Furthermore, the Ag nanoparticles substrate coated with a 10 Å ta-C film shows a higher enhancement of Raman signals than the uncoated substrate. These observations are further supported by our numerical simulations. We suggest that biomolecule detections in analytic assays could be easily realized using ta-C-coated Ag-based substrate for SERS especially in the visible range. The coated substrate also has higher mechanical stability, chemical inertness, and technological compliance, and may be useful, for example, to enhance TiO2 photocatalysis and solar-cell efficiency by the surface plasmons.

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Section: Resultsmentioning

confidence: 99%

Ultrathin Diamond-like Carbon Film Coated Silver Nanoparticles-Based Substrates for Surface-Enhanced Raman Spectroscopy

et al. 2010

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“…3 These features make SERS one of the most powerful techniques for non-destructive, on-site and in vivo analysis of chemical and biological substances. 4 However, the utilization of SERS in determination of trace analytes is restricted by the sophisticated and expensive nanofabrication of highly SERS-active substrates, as well as its limited sensitivity and selectivity for trace substances in complex matrices due to the swamping of the analyte signal in background molecule signals.…”

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confidence: 99%

Coffee-ring effect-based simultaneous SERS substrate fabrication and analyte enrichment for trace analysis

et al. 2014

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Based on the "coffee-ring effect", we developed a highly efficient SERS platform which integrates the fabrication of SERS-active substrates and the preconcentration of analytes into one step. The high sensitivity, robustness, reproducibility and simplicity make this platform ideal for on-site analysis of small volume samples at low concentrations in complex matrices.Since its invention in the 1970s, 1,2 surface-enhanced Raman spectroscopy (SERS) has been receiving growing interest in a variety of areas due to its inherent merits such as a high signalto-noise ratio, non-photobleaching features and the use of single photoexcitation. 3 These features make SERS one of the most powerful techniques for non-destructive, on-site and in vivo analysis of chemical and biological substances. 4 However, the utilization of SERS in determination of trace analytes is restricted by the sophisticated and expensive nanofabrication of highly SERS-active substrates, as well as its limited sensitivity and selectivity for trace substances in complex matrices due to the swamping of the analyte signal in background molecule signals. For example, while the concentrations of PAHs in the environment are commonly in the range of 10 À12 to 10 À9 g L À1 , the lowest detection limits available with a well-designed SERS substrate are in the range of 3 Â 10 À6 to 1.78 Â 10 À4 g L À1 . 5 To meet the requirements for analysis of trace analytes in complex matrices, metallic substrates were tailored to increase the signal strength, and analytes were preconcentrated before SERS analysis. As these two approaches are very complicated and timeconsuming, it is highly desired to develop a fast, simple and robust approach to simultaneously perform the self-assembling of SERS substrates and preconcentration of trace analytes.One technique that holds great promise in this regard is the "coffee-ring effect", which refers to the accumulation of a ringlike dense array on the border by evaporating a droplet of aqueous solution containing nonvolatile solutes such as organic small molecules, biomacromolecules, polymers, and nanoparticle microspheres on solid surfaces. In this process, the three-phase contact line among the atmosphere, droplet and solid substrate is pinned, and a remarkable capillary ow happens because of the evaporation of solvents, driving solutes to move outward from the inner side to the rim of the droplet. Consequently, solutes are highly concentrated along the original droplet edge. It was found that the coffee-ring effect is applicable for enriching both chemical and biological substances. 6-11 One example is its application in normal Raman spectrometry that is termed as drop coating deposition Raman (DCDR). 10 In recent years, the coffee-ring effect has become a powerful tool for self-structuring of nanomaterials. [12][13][14][15] Herein, we report the development of a novel SERS platform by integrating the generation of SERS substrates and the enrichment of analytes into one step. We demonstrate the benets of the coffee-ring effect in co...

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“…A common use of SERS for quantitative analysis is based on SERS tags [10][11][12][13][14], which can be fabricated by placing Raman reporter molecules on the surface of a metal nanoparticle (typically made of Ag or Au) to provide a simple way to code the surface property (e.g. the type of receptor or ligand) of tag with a known SERS spectrum.…”

Section: Introductionmentioning

confidence: 99%

Silica-coated dimers of silver nanospheres as surface-enhanced Raman scattering tags for imaging cancer cells

Xia

2013

Interface Focus.

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One contribution of 10 to a Theme Issue 'Molecular-, nano-and micro-devices for real-time in vivo sensing'. Surface-enhanced Raman scattering (SERS) tags have been actively explored as a multiplexing platform for sensitive detection of biomolecules. Here, we report a new type of SERS tags that was fabricated by sequentially functionalizing dimers made of 50 nm Ag nanospheres with 4-mercaptobenzoic acid as the Raman reporter molecule, silica coating as a protective shell and antibody as a targeting ligand. These dimer-based tags give highly enhanced and reproducible Raman signals owing to the presence of a well-defined SERS hot spot at the junction between two Ag nanospheres in the dimer. The SERS enhancement factor (EF) of an individual dimer tag supported on a glass slide can reach a level as high as 4.3 Â 10 6 . In comparison, the EFs dropped to 2.8 Â 10 5 and 8.7 Â 10 5 , respectively, when Ag nanospheres and nanocubes with sizes similar to the spheres in the dimer were used to fabricate the tags using similar procedures. The SERS signals from aqueous suspensions of the dimer-based tags also showed high intensity and good stability. Potential use of the dimer-based tags was demonstrated by imaging cancer cells overexpressing HER2 receptors with good specificity and high sensitivity.

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SERS as a Foundation for Nanoscale, Optically Detected Biological Labels

Cited by 347 publications

References 51 publications

Ultrathin Diamond-like Carbon Film Coated Silver Nanoparticles-Based Substrates for Surface-Enhanced Raman Spectroscopy

Ultrathin Diamond-like Carbon Film Coated Silver Nanoparticles-Based Substrates for Surface-Enhanced Raman Spectroscopy

Coffee-ring effect-based simultaneous SERS substrate fabrication and analyte enrichment for trace analysis

Silica-coated dimers of silver nanospheres as surface-enhanced Raman scattering tags for imaging cancer cells

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