Environmental Health Perspectives 105, Supplement 5, September 1997: Article by Mollo et al.

Environmental Health Perspectives 105, Supplement 5, September 1997

[ Citation in PubMed ] [ Related Articles ]

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

Laura Mollo, ¹ Valerie Levresse, ² Maria F. Ottaviani, ³ Sophie Ellouk-Achard, ² Marie-Claude Jaurand, ² and Bice Fubini ¹

¹ Università di Torino, Facoltà di Farmacia, Dipartimento di Chimica Inorganica, Chimica Fisica e Chimica dei Materiali, Torino, Italy
² INSERM Unité 139, Créteil, France
³ Università degli Studi di Firenze, Facoltà di Scienze, Dipartimento di Chimica, Firenze, Italy

Abstract
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. -- Environ Health Perspect 105(Suppl 5):1031-1036 (1997)

Key words : spin labels, toxicity, cell response, EPR spectroscopy, nitroxides, toxic particulate, MCM-41 mesoporous silica, mesothelial cells, internalization

This paper is based on a presentation at The Sixth International Meeting on the Toxicology of Natural and Man-Made Fibrous and Non-Fibrous Particles held 15-18 September 1996 in Lake Placid, New York. Manuscript received at EHP 26 March 1997; accepted 8 April 1997.
This research was supported by the Joint European Medical Research Board as a part of a project titled "Chemical modifications occurring at early stages of incubation of fibres in biological media and cell cultures reliable to biopersistence and pathogenicity in vivo." The authors are grateful to D. Brunel and F. Di Renzo, École Nationale Superieure de Chimie de Montpellier (Montpellier, France) for the gift of the MCM-41 mesoporous silica prepared in their laboratory.
Address correspondence to Dr. B. Fubini, Università di Torino, Facoltà di Farmacia, Dipartimento di Chimica Inorganica, Chimica Fisica e Chimica dei Materiali, Via Pietro Giuria 7, 10125 Torino, Italy. Telephone: 39 11 6707566. Fax: 39 11 6707855. E-mail fubini@silver.ch.unito.it
Abbreviations used: EPR, electron paramagnetic resonance; FCS, fetal calf serum; FITC, fluorescein isothiocyanate; TEMPONE, 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl.

[ Table of Contents ] [ Full Article ] [ Citation in PubMed ] [ Related Articles ]

Last Update: October 27, 1997