Synthesis, characterization and examination of Gd[DO3A-hexylamine]-functionalized silica nanoparticles as contrast agent for MRI-applications

Feldmann, Verena; Engelmann, J; Gottschalk, Sven; Mayer, Hermann A.

doi:10.1016/j.jcis.2011.09.053

Cited by 29 publications

(24 citation statements)

References 44 publications

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“…Hydride silica (Si-H) is preferred for applications in which the hydrolytical stability of the siloxane bond is questioned, that is, the use of functionalized silica particles with Gd(III) chelates for magnetic resonance imaging [70]. For sterical reasons direct introduction of Si-O-C bonds from reaction with 1,4-dibromobutane on activated silica is attained with metal preconcentrations purposes [71].…”

Section: Coupling Agentsmentioning

confidence: 99%

Organic Modification of Hydroxylated Nanoparticles: Silica, Sepiolite, and Polysaccharides

Tiemblo

García

Hoyos

et al. 2015

Handbook of Nanoparticles

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The incorporation of organic compounds onto the surface of nanoparticles (NPs) differs from the same reactions carried out on macroscopic surfaces in that the former are characterized by surfaces energies much higher than the latter. Consequently, surface stabilization mechanisms of NPs are very active, and among them NP self-aggregation is the first and most important. In NP surface modification, the ability of the experimental conditions to destroy self-aggregation will determine the extent to which the NP surface is modified and so, the modified NP nature. A second consequence of the high-surface free energy is the NP surface avidity to interact chemically or physically with other compounds: NPs readily adsorb water, gases, vapors, or other higher molecular weight substances, and in the particular case of hydroxylated NP, chemical reactivity is both high and rich. This chapter will deal with the surface modification of silica, sepiolite, and polysaccharides. Experimental strategies, resulting organo-NPs, their structure and properties, and frequent uses and applications of them will be reviewed.

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Section: Coupling Agentsmentioning

confidence: 99%

Organic Modification of Hydroxylated Nanoparticles: Silica, Sepiolite, and Polysaccharides

Tiemblo

García

Hoyos

et al. 2015

Handbook of Nanoparticles

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“…In the first step, the surface of the bare SiO 2 -NP was functionalized with Si-H bonds (Plumere et al , 2009 ). Next, it was modified with carboxylic acid residues by a photochemically induced hydrosilylation reaction of 10-undecylenic acid (Plumere and Speiser , 2007 ) and 3-butanoic acid resulting in MC n + 2 COOH (where n = 1 or 8, Feldmann et al , 2012 ). The synthesis of this precursor material and its full characterization by dynamic light scattering (DLS), scanning electron microscopy (SEM), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy are described in our recent publication .…”

Section: Functionalization Of the Nanoparticlesmentioning

confidence: 99%

“…The concentration of carboxylic acids on the starting materials MC 4 COOH and MC 11 COOH were 640 μ mol/g and 150 μ mol/g, respectively, as quantified by elemental analysis and thermogravimetric analysis as described in Feldmann et al (2012) . It is evident that steric constraints permit to functionalize only a low percentage of the reacting sites on the surface for both types of spacers.…”

Section: Surface Concentration Of Gadoliniummentioning

confidence: 99%

“…MRI measurements and determination of the Gd surface concentration of the materials were performed as described under the Materials and methods section and in Feldmann et al (2012) . The relaxivities per Gd were determined from the slope of the linear fit of the observed relaxation rates vs. the Gd concentration.…”

Section: Biodistribution Studiesmentioning

confidence: 99%

“…Different strategies have been followed to increase relaxivity (Castelli et al , 2008 ;Carniato et al , 2009 ;Moriggi et al , 2009 ). One is to anchor several Gd complexes to nano-sized systems such as silica nanoparticles (SiO 2 -NPs) (Carniato et al , 2010 ;Henig et al , 2010 ;Feldmann et al , 2012 ;Pinho et al , 2012 ). The potential of such SiO 2 -NP systems for diagnosis and therapy has recently gained increased interest (Peer et al , 2007 ;Cho et al , 2008 ;Davis et al , 2008 ).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Multifunctional silica nanoparticles for optical and magnetic resonance imaging

Joshi

Feldmann

Koestner

et al. 2012

Biological Chemistry

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The surface of spherical, nonporous silica nanoparticles (SiO2-NPs) was modified with gadolinium (Gd) complexes, fluorophores, and cell-penetrating peptides to achieve multifunctionality on a single particle. The Gd surface concentrations were 9–16 μmol/g resulting in nanomaterials with high local longitudinal and transversal relaxivities (~1×105 and ~5×105 /mm/s/NP, respectively). Rapid cellular uptake was observed in vitro; however, larger extracellular agglomerates were also formed. In vivo administration revealed a fast distribution throughout the body followed by a nearly complete disappearance of fluorescence in all organs except the lungs, liver, and spleen after 24 h. Such NPs have the potential to serve as efficient multimodal probes in molecular imaging.

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Stepwise Solid‐Phase Synthesis and Solid‐State Electrochemistry of Redox‐Active Viologen Core/Shell‐Structured Modified Silica Materials

et al. 2013

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Core/shell‐structured viologen‐modified Stöber silica particles with diameters of approximately 235 nm are prepared in a stepwise, solid‐phase synthesis. The nonporous and spherical silica base particles are obtained through a sol–gel process from tetraethoxysilane followed by a post‐synthetic calcination step and characterized by means of scanning electron microscopy, nitrogen adsorption/desorption experiments, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, Gay‐Lussac pycnometry in water, and dynamic light scattering. Coating with triethoxysilane yields SiH‐terminated particles, which are further reacted with the linker, 11‐bromo‐1‐undecene, in a thermally induced hydrosilylation. The resulting kinetically inert and thermodynamically stable SiC bond ensures strong attachment to the silica surface. The viologen units are generated by alkylation with 1‐methyl[4,4′]bipyridinium iodide directly on the particle surface. The successful attachment is confirmed by diffuse reflectance UV/Vis, DRIFT, and 13C cross‐polarization/magic‐angle spinning nuclear magnetic resonance spectroscopy. The viologen shell of the particles is electrochemically addressable. In cyclic voltammetry experiments, under three‐phase junction conditions with modified gold and paraffin‐impregnated graphite electrodes, the immobilized viologen units are reduced to the neutral state in two consecutive electron‐transfer reactions via a mono radical cation species. The in situ electrolysis of suspended particles leads to a material with a diamagnetic core (silica) and a paramagnetic shell (viologen mono radical cations). Electron paramagnetic resonance experiments demonstrate that the radical cations are strongly attached to the particle surface. The material and electrochemical properties of the particles are compared to amorphous silica and to a viologen‐modified Stöber material based on a well‐established immobilization strategy (condensation of alkoxysilane to surface silanol groups).

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Synthesis, characterization and examination of Gd[DO3A-hexylamine]-functionalized silica nanoparticles as contrast agent for MRI-applications

Cited by 29 publications

References 44 publications

Organic Modification of Hydroxylated Nanoparticles: Silica, Sepiolite, and Polysaccharides

Organic Modification of Hydroxylated Nanoparticles: Silica, Sepiolite, and Polysaccharides

Multifunctional silica nanoparticles for optical and magnetic resonance imaging

Stepwise Solid‐Phase Synthesis and Solid‐State Electrochemistry of Redox‐Active Viologen Core/Shell‐Structured Modified Silica Materials

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