Silica-Coated Nanocomposites of Magnetic Nanoparticles and Quantum Dots

Yi, Dong Kee; Selvan, Subramanian Tamil; Lee, Su Seong; Papaefthymiou, Georgia C.; Kundaliya, Darshan C.; Ying, Jackie Y.

doi:10.1021/ja0428863

Cited by 835 publications

(590 citation statements)

References 25 publications

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“…Because organic ligand-capped nanoparticles in organic solvent can be miscible with aqueous solutions to form an emulsion in the presence of surfactants, silica encapsulation through a microemulsion method, using surfactants, is useful for the coating of organic-based nanoparticles, and can produce particles which are highly monodisperse. Silica coating of superparamagnetic iron oxide (SPIO) 8 and magnetic nanoparticles (MNs)/quantum dots (QDs), 9 synthesized in organic phase, has been achieved through a water-in-oil microemulsion technique. However, for these particles to be used for biological applications, excess surfactant, used to make the nanoparticles miscible, must be removed.…”

Section: Introductionmentioning

confidence: 99%

Microwave enhanced silica encapsulation of magnetic nanoparticles

et al. 2012

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The surface modification of various nanoparticles with silica has been exploited to increase their utility for bioapplications. However, silica encapsulation through conventional methods requires long reaction times (hours to days). Herein, we demonstrated that uniform and spherical silica encapsulation of magnetic nanoparticles can be achieved within 10 min via microwave irradiation after phase transferring monodisperse magnetic nanoparticles from organic to water phase. In addition, we showed that silica shell addition through microwave synthesis is more effective than conventional heating methods, such as a hot plate. The approach that we propose may be useful in preparing multifunctional nano-probes, particularly for radiolabeling, which requires fast preparation times.

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Section: Introductionmentioning

confidence: 99%

Microwave enhanced silica encapsulation of magnetic nanoparticles

et al. 2012

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“…In the search for high-quality materials, our group choses to adhere to the literature that shows monodisperse spherical materials obtained with the formulation of microemulsions, where the micelles or reverse micelles act as nanoreatores controlling the spherical morphology. 33,34,51,52 Our first attempt was based on a microemulsion prepared with aqueous solutions of magnetite nanoparticles stabilized with tetramethylammonium hydroxide or sodium silicate added to cyclohexane, TEOS, surfactant (Triton X-100) and cosurfactant (n-hexanol). However, after several hours, a silica rich material with ill-defined morphology precipitated.…”

Section: Coating Magnetite With Silicamentioning

confidence: 99%

“…A formulation with the surfactant AOT (bis (2-ethylhexyl) sodium sulfosuccinate) was tested, but after the addition of ammonia, it also precipitated. Organic solutions of magnetite nanoparticles prepared by co-precipitation and stabilized with oleic acid were used in the formulation of a reverse micellar microemulsion with cyclohexane, TEOS and surfactant (Igepal CO-520) (Figure 2), a modification of the method reported by Yi et al 34 This microemulsion resulted in high-quality nanomaterials with spherical morphology.…”

Section: Coating Magnetite With Silicamentioning

confidence: 99%

Recent advances in the development of magnetically recoverable metal nanoparticle catalysts

Rossi¹,

Garcia²,

Vono³

2012

J. Braz. Chem. Soc.

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O objetivo deste Account é fornecer uma visão geral de nossas atividades atuais de pesquisa, as quais envolvem a síntese e modificação de nanomateriais superparamagnéticos para aplicação na área de separação magnética e catálise. Primeiramente, uma introdução ao magnetismo e à separação magnética é feita. Em seguida, estratégias sintéticas que têm sido desenvolvidas para gerar nanopartículas superparamagnéticas revestidas esfericamente por sílica e outros óxidos, com destaque a sistemas bem caracterizados e preparados por metodologias que geram amostras de elevada qualidade e que, a princípio, podem ser produzidas em maior escala, são discutidas. Uma série de catalisadores magneticamente recuperáveis preparados em nosso grupo de pesquisa pela combinação única de suportes superparamagnéticos e nanopartículas metálicas é destacada. Este Account é concluído com observações pessoais e perspectivas neste campo de pesquisa.The aim of this Account is to provide an overview of our current research activities on the design and modification of superparamagnetic nanomaterials for application in the field of magnetic separation and catalysis. First, an introduction of magnetism and magnetic separation is done. Then, the synthetic strategies that have been developed for generating superparamagnetic nanoparticles spherically coated by silica and other oxides, with a focus on well characterized systems prepared by methods that generate samples of high quality and easy to scale-up, are discussed. A set of magnetically recoverable catalysts prepared in our research group by the unique combination of superparamagnetic supports and metal nanoparticles is highlighted. This Account is concluded with personal remarks and perspectives on this research field.

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“…Thus, the above-mentioned magnetic cores can be modified with a broad range of outer shells, e.g. silica (Yi et al 2005;Guerrero-Martinez et al 2010) or polymers (Gupta and Gupta 2005;Rudzka et al 2012;Guo et al 2005). The surface modification of magnetic nanoparticles is crucial for the control of their chemical and physical properties, and colloidal stability, which is very important in their further applications.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, surface characterization and electrokinetic properties of colloidal silica nanoparticles with magnetic core

2016

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In order to obtain functionalized silica colloids with magnetic properties, the three-step reaction, was carried out. The aqueous suspension of iron oxide nanoparticles as magnetic core (maghemite-c-Fe 2 O 3 ) was synthesized according to the Massart's method (Massart in IEEE Trans Magn 17:1247-1248, 1981. A silica shell was obtained onto maghemite employing a modified sol-gel method by Salgueirino (Salgueirino-Maceira et al. in Adv Mater 19:4131-4144, 2006). As-synthesized magnetic silica core/shell nanocomposites were further functionalized by the post-grafting approach, using (3-Aminopropyl)-trimethoxysilane (APTMS) (Pham et al. in Langmuir 18:4915-4920, 2002). The obtained materials were characterized by nitrogen adsorption/desorption measurements, X-ray powder diffractometry (XRD), transmission electron microscopy (TEM). Particle sizes were measured by diffraction laser (DL). In order to establish colloidal stability of the system, zeta potential were measured. The syntheses routes led to obtain both, good purity of maghemite particles (more than 90 %) and their good coverage by outer silica shell. Thanks to their nanometer size and surface properties (especially, presence of amino groups which can ensure the electrostatic interaction between surface of adsorbent and adsorbate molecules), asprepared nanocomposites can be considered as promising

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Silica-Coated Nanocomposites of Magnetic Nanoparticles and Quantum Dots

Cited by 835 publications

References 25 publications

Microwave enhanced silica encapsulation of magnetic nanoparticles

Microwave enhanced silica encapsulation of magnetic nanoparticles

Recent advances in the development of magnetically recoverable metal nanoparticle catalysts

Synthesis, surface characterization and electrokinetic properties of colloidal silica nanoparticles with magnetic core

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