Behavior of fluorescent molecules bound to the interior of silica nanocapsules in various solvents

Miyoshi, Hirokazu; Matsuo, Yuki; Liu, Yiyao; Sakata, Takao; Mori, Hirotarô

doi:10.1016/j.jcis.2008.09.026

Cited by 12 publications

(8 citation statements)

References 22 publications

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“…Coordinated protons can exchange energy with these electrons (for spin-lattice relaxation) and they can reduce their T1 relaxation time without causing distinct line broadening. As reported by Li et al 10 Organic dyes are also frequently used as materials for biolabelling and bio-imaging 16,23,24 . To overcome these weaknesses, researchers have tried to use nanoparticles (NPs) of carbonate [9][10][11]15,16 , oxide [17][18][19] , fluoride 20,21 or phosphate 22 of gadolinium for MR imaging.…”

Section: Introductionmentioning

confidence: 94%

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Fluorescein isothiocyanate embedded silica spheres in gadolinium carbonate shells as novel magnetic resonance imaging and fluorescence bi-modal contrast agents

Liu

Shao

2015

New J. Chem.

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In this study, four bi-modal core-shelled contrast agents of SiO 2 (FITC)@Gd 2 O(CO 3 ) 2 ·H 2 O with varying shell thicknesses but the same cores were prepared via a two-step wet chemistry method. The four samples were quite close to sphericity and their averaged diameters were 127, 140, 148.7 and 174.0 nm. The composition of their shells was also examined. As the shell thickness increased, the fluorescence 10 intensity halved but the longitudinal relaxivity remained high (28, 29, 27, 24 mM -1 s -1 ). The measured relaxivities of the samples were more than 5.8 times higher than the relaxivity of Gd-DTPA-BMA in a 0.55 T MR (magnetic resonance) system. The levels of cytotoxicity were tested on four cell lines (293, HeLa, HFL1, MCF-7) and the results indicated that the samples were safe.The intracellular fluorescence in HeLa cells was clearly observed using laser confocal microscopy. These results showed that this 15 material had potential for use in MR-fluorescence bi-modal imaging.

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Section: Introductionmentioning

confidence: 94%

“…Organic dyes are also frequently used as materials for biolabelling and bio-imaging. 16,23,24 These dyes are very cheap, have low toxicity, and can be modified easily. However, they are subject to the problem of photo-bleaching, as light excitation can cause irreversible damage to the molecules.…”

Section: Introductionmentioning

confidence: 99%

Fluorescein isothiocyanate embedded silica spheres in gadolinium carbonate shells as novel magnetic resonance imaging and fluorescence bi-modal contrast agents

Liu

Shao

2015

New J. Chem.

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“…They determined the rate constants for the entry and exit processes of 1bromonaphthalene in the b-CD cavity. However, we have considered it pertinent to include a separate section for cyclodextrins because they are representative examples of saturable receptors [110], that is, of receptors in which the number of guest molecules is small and well defined (one, or two in some cases). This kind of receptor includes, for example, calixarenes, crown ethers or silica nanoparticles.…”

Section: Cyclodextrins As Receptorsmentioning

confidence: 99%

“…This kind of receptor includes, for example, calixarenes, crown ethers or silica nanoparticles. The latter kind of receptors has been used recently in photochemical studies whose objective was to explore the possibilities of the nanocapsules acting as drug 70 M. Marchena and F. Sanchez carriers [110]. This produces some differences from micelles because, although this kind of receptor is definitively saturable, given the small concentrations of the reactants that generally are employed in photochemical experiments, they behave as, practically, unsaturable receptors.…”

Section: Cyclodextrins As Receptorsmentioning

confidence: 99%

Kinetics of Photochemical Reactions under Restricted Geometry Conditions

Marchena

Sánchez

2010

Progress in Reaction Kinetics and Mechanism

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Kinetics of ground state reactions under restricted geometry conditions have been rationalized generally taking as a basis the Pseudophase Model, whose basic hypothesis is: The distribution of the reactants between the pseudophases is at equilibrium, that is, the rate of the reaction is slow in relation to the rates of entry and exit of the reactant to and from the receptor. However, photochemical reactions are generally very rapid, so the following question emerges: is the Pseudophase Model still applicable to photochemical reactions? To answer this question has been the primary objective of this work in which photochemical reactions in micelles, polymers and cyclodextrins have been reviewed. The lifetime of the fluorophore and the distributions of the quencher and the probe are crucial properties; they must be taken into account to obtain a proper description of the behaviour of a given system. The models of Infelta, Almgren and Quina visualise different scenarios with varied combinations of these properties. It is shown that, in some cases, the Pseudophase Model holds at least formally.

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“…Thus, the Pseudophase Model can be applied to the interpretation of data in, for example, cyclodextrins solutions [ 44 ]. However, we have considered pertinent the inclusion of a separate section for these kinds of receptors, that is, of receptors in which the number of guest molecules is small and well defined (one, or two, in some cases) [ 92 ]. Moreover, as mentioned previously, reactions between two reactants bound to different receptors are possible, in such a way that Equation 63 would apply.…”

Section: Microheterogeneous Catalysis With Participation Of Groundmentioning

confidence: 99%

Microheterogeneous Catalysis

2010

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The catalytic effect of micelles, polymers (such as DNA, polypeptides) and nanoparticles, saturable receptors (cyclodextrins and calixarenes) and more complex systems (mixing some of the above mentioned catalysts) have been reviewed. In these microheterogeneous systems the observed changes in the rate constants have been rationalized using the Pseudophase Model. This model produces equations that can be derived from the Brönsted equation, which is the basis for a more general formulation of catalytic effects, including electrocatalysis. When, in the catalyzed reaction one of the reactants is in the excited state, the applicability (at least formally) of the Pseudophase Model occurs only in two limiting situations: the lifetime of the fluorophore and the distributions of the quencher and the probe are the main properties that define the different situations.

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Behavior of fluorescent molecules bound to the interior of silica nanocapsules in various solvents

Cited by 12 publications

References 22 publications

Fluorescein isothiocyanate embedded silica spheres in gadolinium carbonate shells as novel magnetic resonance imaging and fluorescence bi-modal contrast agents

Fluorescein isothiocyanate embedded silica spheres in gadolinium carbonate shells as novel magnetic resonance imaging and fluorescence bi-modal contrast agents

Kinetics of Photochemical Reactions under Restricted Geometry Conditions

Microheterogeneous Catalysis

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