title: New carboxysilane-coated iron oxide nanoparticles for nonspecific cell labelling.
abstract: Magnetic resonance imaging (MRI) offers the possibility of tracking cells labelled with a contrast agent and evaluating the progress of cell therapies. This requires efficient cell labelling with contrast agents. A basic incubation of cells with iron oxide nanoparticles (NPs) is a common method. This study reports the synthesis at the gram scale of iron oxide nanoparticles as MRI T₂ contrast agents for cell labelling. These NPs are based on small iron oxide cores coated with a thin polysiloxane shell presenting carboxylic acid functions. The iron oxide cores produced have been characterized by transmission electron microscopy, X-ray diffraction, ζ-potential, infrared, photon correlation spectroscopy, atomic force microscopy, magnetometry and relaxometric measurements. These measurements confirmed the expected surface modification by carboxysilane. Carboxylic groups created electrostatic repulsion between NPs when they are deprotonated. Therefore, highly concentrated aqueous solutions of carboxysilane coated iron oxide NPs can be obtained, up to 70% (w/w). These NPs could be used for cell labelling owing to their aggregation and re-dispersion properties. NPs precipitated in Dulbecco's modified Eagle medium induced a rapid association with 3 T6 fibroblast cells and could easily be re-dispersed in phosphate buffer saline solution to obtain properly labelled cells.
authors.affiliation: UMONS, Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, B-7000, Mons, Belgium.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Bridot
authors.forename: Dimitri
authors.initials: D
authors.lastname: Stanicki
authors.forename: Sophie
authors.initials: S
authors.lastname: Laurent
authors.forename: Sébastien
authors.initials: S
authors.lastname: Boutry
authors.forename: Yves
authors.initials: Y
authors.lastname: Gossuin
authors.forename: Philippe
authors.initials: P
authors.lastname: Leclère
authors.forename: Roberto
authors.initials: R
authors.lastname: Lazzaroni
authors.forename: Luce
authors.initials: L
authors.lastname: Vander Elst
authors.forename: Robert N
authors.initials: RN
authors.lastname: Muller
mesh_terms: D000818:Animals; D002460:Cell Line; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003287:Contrast Media / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D005347:Fibroblasts / Q000166:cytology; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D051379:Mice; D012833:Siloxanes / Q000737:chemistry*; D013194:Staining and Labeling
chemical_list: D020099:Coated Materials, Biocompatible; D003287:Contrast Media; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; D012833:Siloxanes; C000499:ferric oxide
keywords: cell labelling; colloidal stability; contrast agent; ferrofluids; iron oxide; nanoparticles; silane