Bifunctional Nanocomposites with Long-Term Stability as SERS Optical Accumulators for Ultrasensitive Analysis

Spuch‐Calvar, Miguel; Rodríguez‐Lorenzo, Laura; Morales, M.P.; Álvarez‐Puebla, Ramón A.; Liz‐Marzán, Luis M.

doi:10.1021/jp810470n

Cited by 69 publications

(61 citation statements)

References 54 publications

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“…Such nanocomposite colloids combine efficient SERS analytical capability with flexible handling for signal accumulation using an external magnetic field, thereby increasing the SERS detection limits. [106] Notably, a similar approach had been used to create magnetic/luminescent colloids, through LbL assembly of CdTe QDs on silica-encapsulated magnetite nanocrystals. [107] Several examples of the silanization of polymer-coated particles based on other polyelectrolytes (different to PVP) have also been reported.…”

Section: Polymer and Surfactant Stabilized Inorganic Particlesmentioning

confidence: 99%

Recent Progress on Silica Coating of Nanoparticles and Related Nanomaterials

2010

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In recent years, new strategies for silica coating of inorganic nanoparticles and organic nanomaterials, which differ from the classical methodologies, have emerged at the forefront of materials science. Silica as a coating material promises an unparalleled opportunity for enhancement of colloidal properties and functions by using core-shell rational designs and profiting from its synthetic versatility. This contribution provides a brief overview of recent progress in the synthesis of silica-coated nanomaterials and their significant impact in different areas such as spectroscopy, magnetism, catalysis, and biology.

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Section: Polymer and Surfactant Stabilized Inorganic Particlesmentioning

confidence: 99%

Recent Progress on Silica Coating of Nanoparticles and Related Nanomaterials

2010

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“…7 For instance, Au nanorods-decorated silicaFe 2 O 3 microspheres concentrated under a magnetic field increased the density of "hot" spots thereby boosting the SERS detection limit. 28 Magnetically aggregated Fe 3 O 4 -Au core-shell nanostructures also demonstrated a higher SERS activity than that of conventional Au NPs under the same conditions. 29 Naturally, the size and density of metal NPs supported on individual microspheres largely affect the total number of "hot" spots formed either between neighboring nanoparticles supported on the same microsphere, or between nanoparticles locating within the contact area of two or more microspheres in the aggregated or self-assembled clusters.…”

Section: Introductionmentioning

confidence: 95%

“…Therefore, controllable growth and distribution of noble metal NPs on Fe 3 O 4 microspheres or on more general magnetic templates is the key to maximizing the SERS sensitivity of such bifunctional composite nanostructures, but has been largely overlooked in previous studies. [7][8][9][10][11][12][13][14][15][16]28,29 This is the second critical problem we are attempting to tackle in the present work.…”

Section: Introductionmentioning

confidence: 99%

Maximizing surface-enhanced Raman scattering sensitivity of surfactant-free Ag-Fe3O4 nanocomposites through optimization of silver nanoparticle density and magnetic self-assembly

Bao

Lei

2013

Journal of Applied Physics

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Magnetic composite nanomaterials consisting of more than two functional constituents have been attracting much research interests due to the realization of multiple functionalities in a single entity. In particular, integration of ferromagnetic oxides and noble metal nanoparticles (NPs) in composites results in simultaneous magnetic activity and optical response where the optical property of the whole system could be modulated by application of an external magnetic field. In this work, we prepared Ag NPs-coated Fe 3 O 4 microspheres as a novel surfactant-free surfaceenhanced Raman scattering (SERS) substrate through a solid-phase thermal decomposition reaction. The SERS sensitivity of the fabricated nanocomposites is maximized by adjusting the size and density of Ag NPs supported on the Fe 3 O 4 microspheres and further increased by magneticfield-directed self-assembly of the composite substrates, with both effects attributed to the efficient generation of plasmonic near-field "hot" spots. At the optimal conditions, the prepared substrate is capable of detecting rhodamine 6G molecules at a concentration down to 10 À12 M, thus demonstrating the great potential of using bifunctional nanocomposites as an excellent candidate for ultra-high sensitive Raman spectroscopy and biosensors. We also reveal the underlying mechanisms responsible for the observed SERS enhancements through full-wave numerical simulations. V C 2013 AIP Publishing LLC. [http://dx

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“…As a result, the studies in the field often involve the contributions of small elements or particles where the dipole approximation may be sufficient to describe the optical response. Examples of applications are on telecommunications [8,9,10], spontaneous emission rates and fluorescence [11,12,13], sensors [14], energy harvesting [15,16], optical forces and trapping [17,18,19,20] or medical therapy [21]. The capabilities and applicability of all these promising examples can be largely enhanced if some degree of tunability is added.…”

Section: Introductionmentioning

confidence: 99%

Radiative corrections to the polarizability tensor of an electrically small anisotropic dielectric particle

et al. 2010

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Radiative corrections to the polarizability tensor of isotropic particles are fundamental to understand the energy balance between absorption and scattering processes. Equivalent radiative corrections for anisotropic particles are not well known. Assuming that the polarization within the particle is uniform, we derived a closed-form expression for the polarizability tensor which includes radiative corrections. In the absence of absorption, this expression of the polarizability tensor is consistent with the optical theorem. An analogous result for infinitely long cylinders was also derived. Magneto optical Kerr effects in non-absorbing nanoparticles with magneto-optical activity arise as a consequence of radiative corrections to the electrostatic polarizability tensor. Astrophys. J. 186, 705-714 (1973). 5. B. T. Draine, "The discrete dipole approximation and its application to interstellar graphite grains," Astrophys.J. 333, 848-872 (1988). 6. B. T. Draine and J. Goodman, "Beyond Clausius-Mossotti: Wave propagation on a polarizable point lattice and the discrete dipole approximation," Astrophys. J. 405, 685-697 (1993). 7. W. L. Barnes, A. Dereux, and T. W. Ebbesen, "Surface plasmon subwavelength optics," Nature 424, 824-830 (2003).

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Bifunctional Nanocomposites with Long-Term Stability as SERS Optical Accumulators for Ultrasensitive Analysis

Cited by 69 publications

References 54 publications

Recent Progress on Silica Coating of Nanoparticles and Related Nanomaterials

Recent Progress on Silica Coating of Nanoparticles and Related Nanomaterials

Maximizing surface-enhanced Raman scattering sensitivity of surfactant-free Ag-Fe3O4 nanocomposites through optimization of silver nanoparticle density and magnetic self-assembly

Radiative corrections to the polarizability tensor of an electrically small anisotropic dielectric particle

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