Design and synthesis of plasmonic magnetic nanoparticles

Lim, JitKang; Tilton, Robert D.; Eggeman, Alexander S.; Majetich, Sara A.

doi:10.1016/j.jmmm.2006.10.1169

Cited by 46 publications

(45 citation statements)

References 27 publications

(26 reference statements)

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“…Gold is much more electron dense than iron or iron oxides, and TEM image formation theory indicates that it is very unlikely for an iron oxide core to appear darker than a surrounding gold shell. Our results for these core/shell nanoparticles are consistent with what we [26] and others [35] have reported earlier for magnetic nanoparticles with thinner (ca. 2 nm) shells, where a lighter core and darker shell are apparent.…”

supporting

confidence: 93%

“…Evidence of surfactant removal was also provided by Fourier transform (FT) IR spectroscopy measurements before and after the transfer. The FTIR spectra [26] show peaks at 2871 and 2922 cm…”

mentioning

confidence: 99%

“…These peak intensities were strongly decreased after TMAOH treatment. [26] Figure 1. Transmission electron microscopy images of Fe 3 O 4 nanoparticles at different stages of the Au coating process: a) an uncoated iron oxide particle, b) after binding small Au clusters to the iron oxide particle surface, c) after reducing more Au to grow the clusters, d) when the clusters have nearly merged into a complete shell, and e) final bifunctional nanoparticles with 18 nm iron oxide cores and a gold shell with an average thickness of ca.…”

mentioning

confidence: 99%

“…MUA was found to have fewer problems with agglomeration and yielded more uniform attachment than the aminosilane reagent used previously. [26,29] The coverage of Au clusters seeded on the iron oxide core affects the homogeneity of the Au shell subsequently created by electroless deposition. Duff's method [30] was employed to synthesize ca.…”

mentioning

confidence: 99%

“…The shell completion reaction took less than 1 min, much less than the formaldehyde reduction used previously. [26] The gold reduction was quenched by the addition of 8 mL of deionized water.…”

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Synthesis and Single‐Particle Optical Detection of Low‐Polydispersity Plasmonic‐Superparamagnetic Nanoparticles

et al. 2008

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Both magnetic and plasmonic particles are of increasing interest for biomedical applications. Magnetic particles are currently used for magnetic separation, to collect tagged cells or DNA sequences, [1][2][3] and for magnetically guided drug delivery. [4][5][6] A key advantage of magnetism lies in the ability to control motion at a distance without perturbing the biological system, as would occur with a large electric field. Noble-metal nanostructures are beneficial not only because of their relative ease of biofunctionalization, but also for plasmonic biosensing. [7][8][9][10] Unlike quantum dots, [11] these particles do not show optical bistability or blinking making them competitive with fluorophores for quantifying the number of cell surface markers. [12,13] The main advantages of plasmonic particles are their extremely large molar extinction coefficients and resonant Rayleigh scattering efficiencies, [8] and the exceptional sensitivity of the surface plasmon resonance peak wavelength to changes in the local dielectric environment. Individual plasmonic nanoparticles and nanorods have been detected by using dark field optical microscopy. [13][14][15][16][17] In fact, by using nonmagnetically responsive gold-coated silica particles ($150 nm), Halas and co-workers have demonstrated the capability of gold-shell nanoparticles in detecting low concentrations of analytes in whole blood within minutes without any sample preparation.[18]Here we describe the preparation of iron oxide/gold core/ shell nanoparticles that can be moved magnetically and imaged optically. The synthesis of large-diameter ($150 nm) magnetic plasmonic three-layer composite particles has previously been reported, [19] but our focus here is on smaller particles. The small size of these nanoparticles approaches that of cellmembrane-bound antigens, and is in a range in which particles can be spontaneously internalized by endocytosis. We expect that the combination of magnetic responsiveness, facile bioconjugation, and a localized surface plasmon resonance in these smaller nanoparticles will open new possibilities for in vitro molecular and cell biological applications, including intracellular mechanical and chemical composition analyses, and magnetophoretic cell sorting according to the expression level of cell surface receptors. The magnetic forcẽ F m ¼ ðm pt Á rÞB * that can be applied to a particle depends on the particle magnetic moment m pt . Since m pt ¼ M s V pt , where M s is the saturation magnetization of the material and V pt is the particle volume, a larger size is generally preferable for a strong magnetic response. Thus there is a compromise between large magnetic moments and the desirability of small sizes for new applications.Gold, silver, and SiO 2 core/Au shell particles have been used for plasmonic sensing, where the surface plasmon peak wavelength shifts in response to small changes in the dielectric environment near the particle surface. A core/shell structure with the noble metal in the shell enables the surface plasmon resona...

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supporting

confidence: 93%

“…Evidence of surfactant removal was also provided by Fourier transform (FT) IR spectroscopy measurements before and after the transfer. The FTIR spectra [26] show peaks at 2871 and 2922 cm…”

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Synthesis and Single‐Particle Optical Detection of Low‐Polydispersity Plasmonic‐Superparamagnetic Nanoparticles

et al. 2008

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Functionalization of Iron Oxide‐Based Magnetic Nanoparticles with Gold Shells

Jagminas

Mikalauskaitė

2019

Photoenergy and Thin Film Materials

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Approaches to the Biofunctionalization of Spherical and Anisotropic Iron Oxide Nanomaterials

Thode

Williams

2009

Nanotechnologies for the Life Sciences

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The sections in this article are Introduction Magnetic Nanoparticle Synthesis Nanoparticle Functionalization Surface Adsorption Ligand Exchange Silanes and Siloxanes Monolayer Reactions Encapsulation Encapsulation: Silica (SiO 2 ) Encapsulation: Metallic and Semiconductor Shells Encapsulation: Polymeric and Carbon Shells Encapsulation: Carbon Shells Lipids and Dendrimers Lipids Dendrimers Conclusions

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Design and synthesis of plasmonic magnetic nanoparticles

Cited by 46 publications

References 27 publications

Synthesis and Single‐Particle Optical Detection of Low‐Polydispersity Plasmonic‐Superparamagnetic Nanoparticles

Synthesis and Single‐Particle Optical Detection of Low‐Polydispersity Plasmonic‐Superparamagnetic Nanoparticles

Functionalization of Iron Oxide‐Based Magnetic Nanoparticles with Gold Shells

Approaches to the Biofunctionalization of Spherical and Anisotropic Iron Oxide Nanomaterials

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