Recent Progress on Silica Coating of Nanoparticles and Related Nanomaterials

Departamento de Química Física and Unidad Asociada CSIC Universidade de Vigo, Vigo 36310, Spain.
Advanced Materials (Impact Factor: 17.49). 03/2010; 22(11):1182-95. DOI: 10.1002/adma.200901263
Source: PubMed


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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Available from: Jorge Pérez-Juste, Oct 01, 2015
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    • "Recently, epitaxial growth of an inorganic shell (mainly including CdS, ZnS, CdSe and SiO 2 ) on the surface of initial QD cores to prepare core/shell QDs has been explored for improving the quality of visible-emitting QDs in aqueous solution [16] [17] [18]. Among these core/shell structures, SiO 2 is one superior hydrophilic coating layer regarding their high stability , good biocompatibility and convenient processability in aqueous media [19] [20]. Nevertheless, the existence of a SiO 2 shell has its own limitation such as the decrease of fluorescence intensity [21] [22]. "
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    ABSTRACT: Highly luminescent, good stable and low toxic N-acetyl-l-cysteine (NAC) capped CdTe/CdS@ZnS-SiO2 near-infrared (NIR)-emitting quantum dots (QDs) were successfully fabricated in aqueous solution via a microwave irradiation reduction route, in which thiol-capped CdTe/CdS QDs were employed as core templates and ZnCl2, NAC and tetraethyl orthosilicate as shell precursors. This presented ZnS-like clusters filled hybrid SiO2 model not only greatly improved the brightness and stability of original CdTe/CdS QDs, but also tremendously decreased the cytotoxicity towards HeLa cells. Furthermore, it was found that Hg2+ could effectively selective quench the QD NIR emission based on electron transfer process. On the basis of this fact, a simple, rapid and specific method for trace Hg2+ determination was proposed. Under optimal conditions, the fluorescence intensity decreased linearly with the concentration of Hg2+ ranging from 5.0 × 10−9 to 1.0 × 10−6 M and the limit of detection for Hg2+ was 1.0 × 10−9 M (S/N = 3). As practical applications, the novel NIR sensor has been demonstrated to monitor and image Hg2+ level in milk power and HeLa cells respectively with satisfactory results obtained.
    Sensors and Actuators B Chemical 02/2015; 207. DOI:10.1016/j.snb.2014.10.031 · 4.10 Impact Factor
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    • "In the last decade, various methodologies for the silica coating of nanoparticles have been developed [21] [26]. Of these methods, reverse microemulsions, as thermodynamically stable, transparent , and isotropic liquid media with nanosized water pools, are particularly powerful [27] [28] [29]. "
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    ABSTRACT: Abstract Core–shell BaMoO4@SiO2 nanospheres were prepared in reverse microemulsions and exhibited enhanced photoluminescence (PL) intensity as compared to that of the uncoated BaMoO4. Characterization was performed using transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDX), and X-ray powder diffraction (XRD). It was found that the silica shell could increase the PL intensity, but the shell is not the thicker the better. The PL emission can be decomposed into three individual Gaussian components: two UV emissions at 308 nm and 369 nm and a visible emission at 448 nm. Such short emission wavelengths can be attributed to quantum size effect of the small BaMoO4 cores (∼16 nm).
    Ceramics International 12/2013; 39(8-8):9293 - 9298. DOI:10.1016/j.ceramint.2013.05.043 · 2.61 Impact Factor
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    • "Small molecule drugs, such as doxorubicin (Dox) and camptothecin, have been loaded onto mesoporous silica nanoparticles and studied for cancer treatment 4-7. Mesoporous silica has also been widely used as a coating material 8, 9. Nanoparticles made from a pyrolysis method, for instance, can be coated with a layer of silica and granted with good stability in aqueous solutions 3, 10-20. "
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    ABSTRACT: We report herein a straightforward and label-free approach to prepare luminescent mesoporous silica nanoparticles. We found that calcination at 400 °C can grant mesoporous organosilica nanoparticles with strong fluorescence of great photo- and chemical stability. The luminescence is found to originate from the carbon dots generated from the calcination, rather than the defects in the silica matrix as was believed previously. The calcination does not impact the particles' abilities to load drugs and conjugate to biomolecules. In a proof-of-concept study, we demonstrated that doxorubicin (Dox) can be efficiently encapsulated into these fluorescent mesoporous silica nanoparticles. After coupled to c(RGDyK), the nanoconjugates can efficiently home to tumors through interactions with integrin αvβ3 overexpressed on the tumor vasculature. This calcination-induced luminescence is expected to find wide applications in silica-based drug delivery, nanoparticle coating, and immunofluorescence imaging.
    Theranostics 08/2013; 3(9):650-7. DOI:10.7150/thno.6668 · 8.02 Impact Factor
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