title: Degradability of superparamagnetic nanoparticles in a model of intracellular environment: follow-up of magnetic, structural and chemical properties.
abstract: The unique magnetic properties of iron oxide nanoparticles have paved the way for various biomedical applications, such as magnetic resonance cellular imaging or magnetically induced therapeutic hyperthermia. Living cells interact with nanoparticles by internalizing them within intracellular acidic compartments. Although no acute toxicity of iron oxide nanoparticles has been reported up to now, the mechanisms of nanoparticle degradation by the cellular environment are still unknown. In the organism, the long term integrity and physical state of iron-based nanoparticles are challenged by iron homeostasis. In this study, we monitored the degradation of 7 nm sized maghemite nanoparticles in a medium mimicking the intracellular environment. Magnetic nanoparticles with three distinct surface coatings, currently evaluated as MRI contrast agents, were shown to exhibit different kinetics of dissolution at an acidic pH in the presence of a citrate chelating agent. Our assessment of the physical state of the nanoparticles during degradation revealed that the magnetic properties, size distribution and structure of the remaining nanocrystals were identical to those of the initial suspension. This result suggests a model for nanoparticle degradation with rapidly dissolved nanocrystals and a reservoir of intact nanoparticles.
authors.affiliation: Laboratoire Matière et Systèmes Complexes, UMR 7057, CNRS and Université Paris Diderot, Paris, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Lévy
authors.forename: Florence
authors.initials: F
authors.lastname: Lagarde
authors.forename: Valentin-Adrian
authors.initials: VA
authors.lastname: Maraloiu
authors.forename: Marie-Geneviève
authors.initials: MG
authors.lastname: Blanchin
authors.forename: François
authors.initials: F
authors.lastname: Gendron
authors.forename: Claire
authors.initials: C
authors.lastname: Wilhelm
authors.forename: Florence
authors.initials: F
authors.lastname: Gazeau
mesh_terms: D002951:Citrates; D003287:Contrast Media / Q000737:chemistry / Q000378:metabolism*; D005290:Ferric Compounds; D006863:Hydrogen-Ion Concentration; D008247:Lysosomes / Q000737:chemistry / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles / Q000737:chemistry / Q000648:ultrastructure*; D008954:Models, Biological; D008956:Models, Chemical; D010316:Particle Size; D000077559:Sodium Citrate; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors
chemical_list: D002951:Citrates; D003287:Contrast Media; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C000499:ferric oxide; D000077559:Sodium Citrate