SERS and the Single Molecule

Moskovits, Martin; Tay, Li‐Lin; Yang, Jun; Haslett, T. L.

doi:10.1007/3-540-44948-5_10

Cited by 209 publications

(200 citation statements)

References 12 publications

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“…For example surface plasmons in silver aggregates give rise to strong surface enhanced Raman scattering. 57 Shalaev and Sarychev 58 developed a theory to calculate the local electromagnetic fields in metal-dielectric films and are able to reconstruct the large absorption in these composites around the percolation threshold. However, they can model absorptions up to 50% only.…”

Section: A the Origin Of The Large Absorptionmentioning

confidence: 99%

Highly absorbing black Mg and rare-earth-Mg switchable mirrors

2004

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Apart from a reflecting and a transparent state, rare-earth-Mg alloys ͑RE-Mg͒ exhibit also a highly absorbing, black state during loading with hydrogen. The occurrence of such a black state is due to the disproportionation into subwavelength size REH 2ϩ⑀ and Mg grains during the first hydrogen loading. While the optical properties of REH x change continuously with a further increase in hydrogen concentration x, Mg changes abruptly from a good reflector to a transparent insulator (MgH 2 ). Thin pure Mg films also show this black state when ͑un͒loaded carefully at elevated temperatures. By using the Bruggeman effective medium approximation in combination with the transfer matrix method it is shown that the coexistence of Mg and MgH 2 grains is the cause of this high absorption. Furthermore, we compare this phenomenon to the high absorption of light observed in metal-dielectric composites.

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Section: A the Origin Of The Large Absorptionmentioning

confidence: 99%

Highly absorbing black Mg and rare-earth-Mg switchable mirrors

2004

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“…This phenomenon had been successfully used to demonstrate spectacular enhancement of sensitivity in Raman sensing [1][2][3][4][5] as well as in fluorescence measurements [6][7][8][9], and had been proposed as a method to increase the efficiency of solar cells [10], detectors [11], and various nonlinear optical devices.…”

Section: Introductionmentioning

confidence: 99%

Coupled-mode theory of field enhancement in complex metal nanostructures

Sun¹,

Khurgin²,

Bratkovsky³

2011

Phys. Rev. B

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We describe a simple yet rigorous theoretical model capable of analytical estimation of plasmonic field enhancement in complex metal structures. We show that one can treat the complex structures as coupled multi-pole modes with highest enhancements obtained due to superposition of high order modes in small particles. The model allows one to optimize the structures for the largest possible field enhancements, which depends on the quality factor of the metal and can be as high as for two spherical particles. The "hot spot"can occur either in the nano-gaps between the particles or near the smaller particles. We trace the optimum field enhancement mechanism to the fact that the extended dipole modes of larger particles act as the efficient antennas while the modes in the gaps or near the smaller particles act as the compact sub-wavelength cavities. We also show how easily our approach can be extended to incorporate large numbers of particles in intricate arrangements.

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“…These NPs are subsequently grown using a silver plating step to decrease the distance between the surfaces and the analyte causing a large increase in SERRS signal, detected by a confocal Raman microprobe. 5,9 The assembly consists of a three-part oligonucleotide scaffolding tethering NPs as shown in Figure 1A. Double-stranded oligonucleotides C (oligo-C) of lengths 15 to 39 base pairs containing the protein binding site of interest were designed to generate appropriate spacing for protein access into the final assemblies, with 12 base pair single-stranded overhangs on each end that are complementary to surface-bound 22 base pair oligonucleotides A or B (oligo-A or oligo-B, DNA sequences in Supporting Information).…”

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confidence: 99%

Detection of Sequence-Specific Protein-DNA Interactions via Surface Enhanced Resonance Raman Scattering

et al. 2007

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Practical and high-throughput assays for probing protein-ligand interactions are essential for proteomics and drug development. 1 For example, the analysis of multiprotein complexes involved in gene regulation is a combinatorial challenge with applications in medical diagnostics. 2 Here we describe an approach using surfaceenhanced resonance Raman scattering (SERRS) for protein sensing in a tightly controlled assembly of gold nanoparticles and DNA, which has great potential for high sensitivity with high-throughput multiplexing capacity. 3 SERRS techniques greatly enhance signal strength and sensitivity in many applications, with demonstrations of detection limits at the single-molecule level, 4,5 while offering other important benefits over fluorescent detection methods, including resistance to photobleaching and narrow emission peaks for spectral multiplexing. 6 However, the enhancement possible from SERRS is very dependent on the distance between, the surface morphology of, and the optical resonance of closely associated metal nanoparticles, making the design of controlled assemblies paramount to correctly position analytes for optimal detection. 7 We describe an effective architecture of DNA-bridged nanoparticle assemblies for binding and detecting sequence and concentration dependent protein-DNA interactions. Each short stretch of duplex DNA, which is to be bound by the analyte protein, is prepared with overhangs that hybridize and cross-link a generic set of gold nanoparticles (NPs) functionalized with complementary DNA. 8 This self-assembling scaffold allows control of the positioning of metallic NPs to directly surround a DNA sequence recognized by an analyte protein (tagged with a resonance Raman molecule). These NPs are subsequently grown using a silver plating step to decrease the distance between the surfaces and the analyte causing a large increase in SERRS signal, detected by a confocal Raman microprobe. 5,9 The assembly consists of a three-part oligonucleotide scaffolding tethering NPs as shown in Figure 1A. Double-stranded oligonucleotides C (oligo-C) of lengths 15 to 39 base pairs containing the protein binding site of interest were designed to generate appropriate spacing for protein access into the final assemblies, with 12 base pair single-stranded overhangs on each end that are complementary to surface-bound 22 base pair oligonucleotides A or B (oligo-A or oligo-B, DNA sequences in Supporting Information). Gold NPs diameter of ∼13 nm were prepared by citrate reduction of gold aurate, 11 and the resultant citrate shell was displaced by thiolmodified oligo-A or oligo-B 10 . Conjugates were determined to have 183 ( 20 oligonucleotides per particle (Supporting Information). Nanoparticles of this size have previously been used as seeds for silver plating and multiplexed detection by SERRS. 11 Upon annealing of the single-stranded overhangs, the three components condense into assemblies. 10 Variations of assemblies were formed with oligo-C containing the GCGC recognition site of M.HhaI, 12 the T...

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SERS and the Single Molecule

Cited by 209 publications

References 12 publications

Highly absorbing black Mg and rare-earth-Mg switchable mirrors

Highly absorbing black Mg and rare-earth-Mg switchable mirrors

Coupled-mode theory of field enhancement in complex metal nanostructures

Detection of Sequence-Specific Protein-DNA Interactions via Surface Enhanced Resonance Raman Scattering

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