Use of Nitroxides as Topological Monitors of the Interaction of Silica-Based Particles with Components of the Biological Environment

Ottaviani, M. Francesca; Mollo, Laura; Fubini, Bice

doi:10.1006/jcis.1997.4926

Cited by 24 publications

(9 citation statements)

References 26 publications

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“…The minor component (15%) showed faster mobility, which indicated that a portion of the interacting sites (weakly interacting sites) gave more mobile labels. A previous study also supported this finding (13). The present analysis indicates that the first sites which were labeled were the strongly interacting sites.…”

Section: Characterization Of the Surface Properties Of Fibers By Meansupporting

confidence: 89%

“…As one of the goals of the research was the preparation of labeled fibers to be used in biological media (12), we adopted the labeling procedure reported by Hall and Waterton, which yields covalent-bonded chains stable in aqueous media (12,13). Scheme 1 shows the labeling procedure, which is as follows: the fibers were washed thoroughly with dilute hydrochloric acid and then with doubly distilled water to remove contaminants and traces of iron.…”

Section: Labeling Proceduresmentioning

confidence: 99%

“…In this respect stable radicals (spin labels or spin probes) are suitable for investigating small variations in the microtopography of the surface they are sitting on (10,11). The computer-aided analysis of electron paramagnetic resonance (EPR) spectra of spin labels attached to surfaces has been successfully employed to provide structural and dynamic information on different surface functions and their environment and to monitor interactions between particles and cells (12,13).…”

Section: Introductionmentioning

confidence: 99%

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Surface Properties of Vitreous Fibers

Ottaviani

Tomatis

Fubini

2000

Journal of Colloid and Interface Science

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Section: Characterization Of the Surface Properties Of Fibers By Meansupporting

confidence: 89%

Section: Labeling Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Surface Properties of Vitreous Fibers

Ottaviani

Tomatis

Fubini

2000

Journal of Colloid and Interface Science

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“…This method, tested on a very peculiar type of high surface area mesoporous silica (MCM-41) would seem applicable to virtually any particle or fiber surface provided that silica is a major constituent of the solid and consistent patches of silanols are available. Using the same chemical procedure, spin labels have in fact been linked to a large variety of crystalline and amorphous silica as well as to glass fibers (22). Because of the much lower surface area of these materials with respect to MCM-4 1, their use in cell culture requires a much larger number of cells to obtain enough material for EPR measurement.…”

Section: Resultsmentioning

confidence: 99%

Study of the Stability of a Paramagnetic Label Linked to Mesoporous Silica Surface in Contact with Rat Mesothelial Cells in Culture

Mollo¹,

Levresse²,

Ottaviani³

et al. 1997

Environmental Health Perspectives

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Stable radicals detectable by electron paramagnetic resonance (EPR) may be of use in the investigation of early events in cell-particle toxicity. Piperidine-N-oxyl derivatives (nitroxides), covalently linked to the surface of a high surface area silica (used as model solid for the technique), served as probes in the investigation of the effects of incubation of silica particles with mesothelial cells. A mesoporous silica (MCM-41), prepared by precipitation from a micellar solution, was the most appropriate silica-based particle for this purpose, as its channels allow direct contact with small molecules but not with macromolecules. The cytotoxicity of this amorphous silica is very low, allowing relatively high particle loading in the cell cultures. Both the high surface area of the sample and the large amount of inorganic material extracted from the cell culture provide enough material to run reasonably intense EPR spectra. Computer-aided analysis of the EPR spectra of silica-bound nitroxides provided information on the sensitivity of the labeled silica monitoring different environments, e.g., to follow the path of particles in a mammalian cell culture. Upon contact of the particles with mesothelial cells, the mean distance among the labels at the silica surface decreased as a consequence of the release of oxidizing and/or radical moieties from the cells.

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“…In addition to the NMR spectroscopy,7–9 the structure and physicochemical properties of the rubber–silica interface are suited to be investigated by dynamic EPR spectroscopy which opens a window on the unexploited characteristics of the segmental chain dynamics within the range between 10 6 –10 11 s −1 and it is also capable of affording parameters of significant value with respect to the mechanical properties and chemical reactivity, as the ‘glass transition temperature’ ( T 50g ) and the order parameter S . Pursuiving previous research lines carried out in this10 as well as other laboratories,11–13 in this paper we refer on the synthesis and use of novel spin labelled silicas for investigating the chain dynamics at the interfaces of SBR rubber–SiO 2 blends. Synthetic methods purposely adapted were used for obtaining probes of variable chain length suited for exploiting the rubber–filler interface regions at different depth ranges.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of spin labelled silica and EPR molecular dynamics study at silica–polymer interfaces

Dondi

Pepori

Buttafava

et al. 2011

J of Physical Organic Chem

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Information concerning the interface structure in filler/polymer composites is of key importance for the rationalization of reaction mechanisms in mechano-chemical (extrusion, blending, etc.), thermal or radiation induced free radical processes and for elucidating the factors underlying the reinforcing mechanism. The analysis of the chain dynamics is a suitable tool for undertaking such investigations because any reactivity parameter (rate constants, collisional frequencies, activation energies) and bonding interactions are strictly related to the mobility of the interacting centres. EPR spectroscopy coupled with specific spin labelling at the filler/polymer interface is a tool for making such novel perspective available. In this work, a spin labelling study of the molecular motion at the filler-rubber interface in a silica-SBR blend is reported. Spin labels of different length, spanning a 9-11 Å depth and linked to the surface of silica particles, were prepared and used for determining the rotational diffusion tensors, the T 50 and order parameter in silica/SBR interfaces. The measurements carried out as a function of the temperature in comparison with unbound spin probes dispersed in the rubber matrix have afforded information consistent with the structure of the interfaces predicted by molecular-level theoretical models.

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Use of Nitroxides as Topological Monitors of the Interaction of Silica-Based Particles with Components of the Biological Environment

Cited by 24 publications

References 26 publications

Surface Properties of Vitreous Fibers

Surface Properties of Vitreous Fibers

Study of the Stability of a Paramagnetic Label Linked to Mesoporous Silica Surface in Contact with Rat Mesothelial Cells in Culture

Synthesis of spin labelled silica and EPR molecular dynamics study at silica–polymer interfaces

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