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A comparative study of non-covalent encapsulation methods for organic dyes into silica nanoparticles.

Auger A, Samuel J, Poncelet O, Raccurt O - Nanoscale Res Lett (2011)

Bottom Line: Nevertheless, the behaviour and effect of such luminescent molecules appear to have been much less studied and may possibly prevent the encapsulation process from occurring.Mainly, the photophysical characteristics of the dyes are retained upon their encapsulation into the silica matrix, leading to fluorescent silica nanoparticles.This feature article surveys recent research progress on the fabrication strategies of these dye-doped silica nanoparticles.

View Article: PubMed Central - HTML - PubMed

Affiliation: CEA Grenoble, Department of Nano Materials, NanoChemistry and NanoSafety Laboratory (DRT/LITEN/DTNM/LCSN), 17 rue des Martyrs, 38054 Grenoble Cedex 9, France. aurelien.auger@cea.fr.

ABSTRACT
Numerous luminophores may be encapsulated into silica nanoparticles (< 100 nm) using the reverse microemulsion process. Nevertheless, the behaviour and effect of such luminescent molecules appear to have been much less studied and may possibly prevent the encapsulation process from occurring. Such nanospheres represent attractive nanoplatforms for the development of biotargeted biocompatible luminescent tracers. Physical and chemical properties of the encapsulated molecules may be affected by the nanomatrix. This study examines the synthesis of different types of dispersed silica nanoparticles, the ability of the selected luminophores towards incorporation into the silica matrix of those nanoobjects as well as the photophysical properties of the produced dye-doped silica nanoparticles. The nanoparticles present mean diameters between 40 and 60 nm as shown by TEM analysis. Mainly, the photophysical characteristics of the dyes are retained upon their encapsulation into the silica matrix, leading to fluorescent silica nanoparticles. This feature article surveys recent research progress on the fabrication strategies of these dye-doped silica nanoparticles.

No MeSH data available.


TEM images of silica nanoparticles with different average sizes. (A) 1b (44 ± 3 nm), (B) 2b (46 ± 3 nm), (C) 1 h (46 ± 3 nm), (D) 2b (47 ± 4 nm), (E) 4b (40 ± 3 nm) and (F) 4a (41 ± 4 nm). Scale bar: 100 nm.
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Figure 2: TEM images of silica nanoparticles with different average sizes. (A) 1b (44 ± 3 nm), (B) 2b (46 ± 3 nm), (C) 1 h (46 ± 3 nm), (D) 2b (47 ± 4 nm), (E) 4b (40 ± 3 nm) and (F) 4a (41 ± 4 nm). Scale bar: 100 nm.

Mentions: Figure 2 shows TEM images of three different series (1, 2 and 4) of silica nanoparticles prepared in this study. No example illustrates the series 3. Indeed, due to the porosity of the material obtained at the extremely low pressure required for TEM analysis, the sample was (collapsed) crushed on itself and the pictures observed were not characteristic of the material. Cryo-TEM analysis of the material is under investigation in our laboratories and will be reported in a different manuscript. Overall, the resulting luminescent probes are spherical in shape, and average diameters of 44 ± 3, 47 ± 4 and 41 ± 4 nm have been observed for samples of each series ca. 1b, 2b and 4a, respectively. The images also showed that the particles were monodispersed. Further TEM images of samples 1g 48 ± 4 nm and 1 h 46 ± 3 nm are also available in Figure 2 so that to emphasise the size homogeneity obtained for different samples of the series 1. Dynamic laser light scattering measurements show that the hydrodynamic diameters (the apparent diameter of the hydrated/solvated particles) of each particle of each series (1-4) are slightly larger than the dry particle diameters observed from the TEM. The hydrodynamic diameters of the luminescent nanoparticles may be considerably larger than their 'dry' diameters due to the existence of a water layer surrounding the hydrophilic silica network. Therefore the following diameters of 58, 50, 51 and 44 nm were recorded for samples of each series, ca. 1c, 2d, 3e and 4c, respectively, as illustrated in Figure 3. Overall the TEM and DLS analyses have confirmed similar sizes, morphologies and dispersivity of the silica nanoparticles prepared using the different protocols.


A comparative study of non-covalent encapsulation methods for organic dyes into silica nanoparticles.

Auger A, Samuel J, Poncelet O, Raccurt O - Nanoscale Res Lett (2011)

TEM images of silica nanoparticles with different average sizes. (A) 1b (44 ± 3 nm), (B) 2b (46 ± 3 nm), (C) 1 h (46 ± 3 nm), (D) 2b (47 ± 4 nm), (E) 4b (40 ± 3 nm) and (F) 4a (41 ± 4 nm). Scale bar: 100 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211415&req=5

Figure 2: TEM images of silica nanoparticles with different average sizes. (A) 1b (44 ± 3 nm), (B) 2b (46 ± 3 nm), (C) 1 h (46 ± 3 nm), (D) 2b (47 ± 4 nm), (E) 4b (40 ± 3 nm) and (F) 4a (41 ± 4 nm). Scale bar: 100 nm.
Mentions: Figure 2 shows TEM images of three different series (1, 2 and 4) of silica nanoparticles prepared in this study. No example illustrates the series 3. Indeed, due to the porosity of the material obtained at the extremely low pressure required for TEM analysis, the sample was (collapsed) crushed on itself and the pictures observed were not characteristic of the material. Cryo-TEM analysis of the material is under investigation in our laboratories and will be reported in a different manuscript. Overall, the resulting luminescent probes are spherical in shape, and average diameters of 44 ± 3, 47 ± 4 and 41 ± 4 nm have been observed for samples of each series ca. 1b, 2b and 4a, respectively. The images also showed that the particles were monodispersed. Further TEM images of samples 1g 48 ± 4 nm and 1 h 46 ± 3 nm are also available in Figure 2 so that to emphasise the size homogeneity obtained for different samples of the series 1. Dynamic laser light scattering measurements show that the hydrodynamic diameters (the apparent diameter of the hydrated/solvated particles) of each particle of each series (1-4) are slightly larger than the dry particle diameters observed from the TEM. The hydrodynamic diameters of the luminescent nanoparticles may be considerably larger than their 'dry' diameters due to the existence of a water layer surrounding the hydrophilic silica network. Therefore the following diameters of 58, 50, 51 and 44 nm were recorded for samples of each series, ca. 1c, 2d, 3e and 4c, respectively, as illustrated in Figure 3. Overall the TEM and DLS analyses have confirmed similar sizes, morphologies and dispersivity of the silica nanoparticles prepared using the different protocols.

Bottom Line: Nevertheless, the behaviour and effect of such luminescent molecules appear to have been much less studied and may possibly prevent the encapsulation process from occurring.Mainly, the photophysical characteristics of the dyes are retained upon their encapsulation into the silica matrix, leading to fluorescent silica nanoparticles.This feature article surveys recent research progress on the fabrication strategies of these dye-doped silica nanoparticles.

View Article: PubMed Central - HTML - PubMed

Affiliation: CEA Grenoble, Department of Nano Materials, NanoChemistry and NanoSafety Laboratory (DRT/LITEN/DTNM/LCSN), 17 rue des Martyrs, 38054 Grenoble Cedex 9, France. aurelien.auger@cea.fr.

ABSTRACT
Numerous luminophores may be encapsulated into silica nanoparticles (< 100 nm) using the reverse microemulsion process. Nevertheless, the behaviour and effect of such luminescent molecules appear to have been much less studied and may possibly prevent the encapsulation process from occurring. Such nanospheres represent attractive nanoplatforms for the development of biotargeted biocompatible luminescent tracers. Physical and chemical properties of the encapsulated molecules may be affected by the nanomatrix. This study examines the synthesis of different types of dispersed silica nanoparticles, the ability of the selected luminophores towards incorporation into the silica matrix of those nanoobjects as well as the photophysical properties of the produced dye-doped silica nanoparticles. The nanoparticles present mean diameters between 40 and 60 nm as shown by TEM analysis. Mainly, the photophysical characteristics of the dyes are retained upon their encapsulation into the silica matrix, leading to fluorescent silica nanoparticles. This feature article surveys recent research progress on the fabrication strategies of these dye-doped silica nanoparticles.

No MeSH data available.