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Gold-Speckled Multimodal Nanoparticles for Noninvasive Bioimaging.

Sharma P, Brown SC, Bengtsson N, Zhang Q, Walter GA, Grobmyer SR, Santra S, Jiang H, Scott EW, Moudgil BM - Chem Mater (2008)

Bottom Line: Multimodal Gold-speckled silica nanoparticles as contrast agents for noninvasive imaging with magnetic resonance imaging and photoacoustic tomography have been prepared in a simple one-pot synthesis using nonionic microemulsions.Magnetic resonance contrast is provided through gadolinium incorporated in the silica matrix, whereas the photoacoustic signal originates from nonuniform, discontinuous gold nanodomains speckled across the silica surface.

View Article: PubMed Central - PubMed

Affiliation: Materials Science and Engineering and Particle Engineering Research Center, Molecular Genetics and Microbiology, Biomedical Engineering, Physiology and Functional Genomics, and Department of Surgery, University of Florida, P.O. Box 116135 Gainesville, Florida 32611, and NanoScience Technology Center, Chemistry and Biomolecular Science Center, University of Central Florida, Orlando, Florida 32826.

ABSTRACT
Multimodal Gold-speckled silica nanoparticles as contrast agents for noninvasive imaging with magnetic resonance imaging and photoacoustic tomography have been prepared in a simple one-pot synthesis using nonionic microemulsions. Magnetic resonance contrast is provided through gadolinium incorporated in the silica matrix, whereas the photoacoustic signal originates from nonuniform, discontinuous gold nanodomains speckled across the silica surface.

No MeSH data available.


High-resolution TEM picture of the nanoparticle showing the lattice planes of gold nanoparticles as deposited on the silica nanoparticle.
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fig2: High-resolution TEM picture of the nanoparticle showing the lattice planes of gold nanoparticles as deposited on the silica nanoparticle.

Mentions: A key difference between the current particles and those previously described in the literature lies in the nature of the gold nanoparticle generation and deposition on and in the silica matrix. In a traditional synthesis route (seed-mediated synthesis), 1−2 nm uniform gold nanoparticles are first deposited on the silica surface as small clusters. In the following step, gold nanoshell is created by allowing further deposition and growth of these gold clusters. The shell thickness of the gold nanoshells can vary between 1−20 nm. Unlike the traditional approach of depositing gold nanoparticles21,27 onto silica nanoparticles, we incubated Gd-doped silica nanoparticle within the aqueous core of the microemulsion with chloroauric acid, allowing gold ions to permeate further into the mesoporous silica matrix. Upon reduction a unique gold-speckled surface results due to the deposition of the gold nanodomains. Via this method discontinuous, randomly deposited, sometimes templated, and often irregular gold nanoclusters are formed within and on the surface of the silica core. High-resolution TEM (HRTEM) micrographs of ∼100 nm Gd-doped GSS nanoparticles (prepared at W0 = 10) demonstrate speckled surface deposits of gold, as seen in areas of darker contrast on the silica surface (Figure 1C) and as areas of lighter contrast in the dark-field TEM picture (Figure 1D). Note that Gd doping also contributes to the background as a darker and lighter haze in Figure 1, parts C and D, respectively. The HRTEM micrograph (Figure 2) shows scattered deposition of gold nanoparticles ranging from less than 1 to 5 nm, with varying crystallinity, on the silica surface. These random and irregular clustered deposits, which include templated deposits within the mesopores, make this class of particles distinct and provide for their unique optical properties such as efficient photothermal properties. Since these particles were also doped with Gd ions—a paramagnetic species that affects the longitudinal relaxation rate of water—they exhibited MRI contrast.


Gold-Speckled Multimodal Nanoparticles for Noninvasive Bioimaging.

Sharma P, Brown SC, Bengtsson N, Zhang Q, Walter GA, Grobmyer SR, Santra S, Jiang H, Scott EW, Moudgil BM - Chem Mater (2008)

High-resolution TEM picture of the nanoparticle showing the lattice planes of gold nanoparticles as deposited on the silica nanoparticle.
© Copyright Policy - open-access - ccc-price
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2664628&req=5

fig2: High-resolution TEM picture of the nanoparticle showing the lattice planes of gold nanoparticles as deposited on the silica nanoparticle.
Mentions: A key difference between the current particles and those previously described in the literature lies in the nature of the gold nanoparticle generation and deposition on and in the silica matrix. In a traditional synthesis route (seed-mediated synthesis), 1−2 nm uniform gold nanoparticles are first deposited on the silica surface as small clusters. In the following step, gold nanoshell is created by allowing further deposition and growth of these gold clusters. The shell thickness of the gold nanoshells can vary between 1−20 nm. Unlike the traditional approach of depositing gold nanoparticles21,27 onto silica nanoparticles, we incubated Gd-doped silica nanoparticle within the aqueous core of the microemulsion with chloroauric acid, allowing gold ions to permeate further into the mesoporous silica matrix. Upon reduction a unique gold-speckled surface results due to the deposition of the gold nanodomains. Via this method discontinuous, randomly deposited, sometimes templated, and often irregular gold nanoclusters are formed within and on the surface of the silica core. High-resolution TEM (HRTEM) micrographs of ∼100 nm Gd-doped GSS nanoparticles (prepared at W0 = 10) demonstrate speckled surface deposits of gold, as seen in areas of darker contrast on the silica surface (Figure 1C) and as areas of lighter contrast in the dark-field TEM picture (Figure 1D). Note that Gd doping also contributes to the background as a darker and lighter haze in Figure 1, parts C and D, respectively. The HRTEM micrograph (Figure 2) shows scattered deposition of gold nanoparticles ranging from less than 1 to 5 nm, with varying crystallinity, on the silica surface. These random and irregular clustered deposits, which include templated deposits within the mesopores, make this class of particles distinct and provide for their unique optical properties such as efficient photothermal properties. Since these particles were also doped with Gd ions—a paramagnetic species that affects the longitudinal relaxation rate of water—they exhibited MRI contrast.

Bottom Line: Multimodal Gold-speckled silica nanoparticles as contrast agents for noninvasive imaging with magnetic resonance imaging and photoacoustic tomography have been prepared in a simple one-pot synthesis using nonionic microemulsions.Magnetic resonance contrast is provided through gadolinium incorporated in the silica matrix, whereas the photoacoustic signal originates from nonuniform, discontinuous gold nanodomains speckled across the silica surface.

View Article: PubMed Central - PubMed

Affiliation: Materials Science and Engineering and Particle Engineering Research Center, Molecular Genetics and Microbiology, Biomedical Engineering, Physiology and Functional Genomics, and Department of Surgery, University of Florida, P.O. Box 116135 Gainesville, Florida 32611, and NanoScience Technology Center, Chemistry and Biomolecular Science Center, University of Central Florida, Orlando, Florida 32826.

ABSTRACT
Multimodal Gold-speckled silica nanoparticles as contrast agents for noninvasive imaging with magnetic resonance imaging and photoacoustic tomography have been prepared in a simple one-pot synthesis using nonionic microemulsions. Magnetic resonance contrast is provided through gadolinium incorporated in the silica matrix, whereas the photoacoustic signal originates from nonuniform, discontinuous gold nanodomains speckled across the silica surface.

No MeSH data available.