title: Study of the stability of a paramagnetic label linked to mesoporous silica surface in contact with rat mesothelial cells in culture.
abstract: Stable radicals detectable by electron paramagnetic resonance (EPR) may be 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.
authors.affiliation: Univeristà di Torino, Facoltà di Farmacia, Dipartimento di Chimica Inorganica, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Mollo
authors.forename: V
authors.initials: V
authors.lastname: Levresse
authors.forename: M F
authors.initials: MF
authors.lastname: Ottaviani
authors.forename: S
authors.initials: S
authors.lastname: Ellouk-Achard
authors.forename: M C
authors.initials: MC
authors.lastname: Jaurand
authors.forename: B
authors.initials: B
authors.lastname: Fubini
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004578:Electron Spin Resonance Spectroscopy; D004847:Epithelial Cells / Q000378:metabolism; D004848:Epithelium / Q000737:chemistry / Q000378:metabolism; D008823:Micelles; D010316:Particle Size; D010994:Pleura / Q000166:cytology / Q000378:metabolism; D011506:Proteins / Q000737:chemistry; D051381:Rats; D012822:Silicon Dioxide / Q000737:chemistry*; D013113:Spin Labels; D013499:Surface Properties
chemical_list: D008823:Micelles; D011506:Proteins; D013113:Spin Labels; D012822:Silicon Dioxide