Synthesis and Characterization of Monodisperse Colloidal Organo-silica Spheres

Blaaderen, Alfons van; Vrij, A.

doi:10.1006/jcis.1993.1073

Cited by 414 publications

(373 citation statements)

References 23 publications

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“…TES (Fluka, freshly distilled) was added under vigorous stirring, immediately followed by the addition of APS-FITC. The APS participates with TES in the hydrolysis/condensation reactions and is thereby incorporated into the resulting silica, 8 taking the coupled FITC molecules with it. The dispersions became turbid after a few minutes as a result of light scattered by the growing particles.…”

Section: Methodsmentioning

confidence: 99%

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Spectroscopy of Fluorescein (FITC) Dyed Colloidal Silica Spheres

et al. 1999

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We have measured the absorption spectrum, the emission spectrum, the emission lifetime, and the photostability of fluorescein isothiocyanate (FITC) incorporated inside colloidal silica spheres as a function of the dye concentration in the spheres, while minimizing scattering effects. Six batches of stable, monodisperse particles were synthesized with FITC up to high densities of 0.03 M. At dye concentrations above 0.001 M, we observe a large red shift of 10 nm in the absorption and the emission spectra, as well as a strong reduction of the lifetime. At the same time, the photostability of the dye is considerably improved. These effects are caused by an increased energy transfer between the dye molecules as their concentration increases. Several excitation quenching models are examined, namely annihilation quenching, surface quenching, and a fractal distribution of quenchers. None of the models that assume a homogeneous distribution of FITC provide a sufficient explanation of the observed effects. It is suggested that the dye molecules tend to form clusters during the synthesis of the colloidal spheres. It is concluded that colloids with a low dye concentration are useful for photonic applications, whereas high dye concentrations are interesting for optical experiments in colloid science.

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Section: Methodsmentioning

confidence: 99%

“…silica spheres. 7,8 Therefore, it is crucial to identify the spectroscopic behavior of dye-laced colloids before studying collective photonic effects. A closely related subject that may benefit from dyed colloids is laser action in random media.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopy of Fluorescein (FITC) Dyed Colloidal Silica Spheres

et al. 1999

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“…It is also affected by the nature of surfactant molecules and the molar ratios of water to surfactant and co-surfactant to surfactant for the microemulsion process (44). Nanoparticles prepared with the microemulsion method are spheres with smooth surfaces and low polydispersity, whereas Stöber nanoparticles with smaller radii (<100 nm) are less monodisperse, less spherical, and less smooth (43).…”

Section: Nanoparticle Characterizationmentioning

confidence: 99%

Watching Silica Nanoparticles Glow in the Biological World

Wang¹,

Wang²,

Santra³

et al. 2006

Anal. Chem.

349

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4 7 F Fluorescence-based detection techniques have been widely used in modern biochemical research and disease diagnosis. For the detection of trace levels of analytes, organic fluorophores are commonly exploited as signal transduction tools. Although these fluorophores are versatile and easy to use, their molecular nature determines their limitations. In most cases, only one or a few fluorophores can signal one biomolecule recognition event, and typically, only a limited number of fluorophores can be attached to a biomolecule without interfering with its binding specificity or causing it to precipitate. As a consequence, sample analysis can be particularly difficult when trace amounts of biological analytes are present, and the additional steps required for signal amplification can be time-consuming and impede analyte quantitation.When exposed to a continuous light source, organic fluorophores are not very photostable. In addition, the complex environment inside living cells can increase the vulnerability of organic fluorophores to degradation and photobleaching. These two factors can result in false-positive and false-negative signals and can affect prolonged cell monitoring and 3-D optical sectioning imaging. Moreover, although most organic fluorophores can be conjugated with biomolecules, such as DNA and proteins, a different conjugation chemistry must be used to attach the organic dye to a given biomolecule of interest; this chemistry can be too difficult, time-consuming, and/or expensive for routine applications. All of these limitations have greatly hindered the use of fluorophores for in vitro assays and in vivo cellular imaging.The rapidly evolving field of nanoscience and nanotechnology has opened up a promising era in new biomarker development, in which nanoparticles of various shapes, sizes, and compositions have been successfully used in bioimaging, labeling, and sensing because of their unique optical properties, high surface-to-volume ratio, and other size-dependent qualities (1-8). With manipulated composition and surface modification, these nanoparticle probes have enhanced the fluorescence signal, increased sensitivity, prolonged detection time, and generated better reproducibility.Quantum dots (QDs) and dye-doped nanoparticles are representative fluorescent nanoparticle probes of increasing research interest. QDs are ultrasmall (usually 1-10 nm in diameter), bright (20ϫ brighter than most organic fluorophores), and highly photostable nanocrystalline semiconductors. Their broad excitation spectra, along with narrow, symmetric, size-tunable fluorescence emission spanning the UV to NIR, make them ideal for multiplex analysis (simultaneous detection of multiple an-

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“…A mudança de uma ligação Si-O para Si-C, transforma silício Q em silício T causando uma mudança de aproximadamente 45 ppm e uma separação entre eles também de 10 ppm (T 3 ~ -65 ppm, T 2 ~ -55 ppm, etc) 25 . A Tabela 4 apresenta as proporções entre espécies de silício nas amostras, calculadas através da integração dos picos.…”

Section: Tabela 2 Resultados Da Análise Elementar De Cnh Para As Amounclassified