title: Modification of the Stöber process by a polyazamacrocycle leading to unusual core-shell silica nanoparticles.
abstract: In the view of designing functional nanoparticles, the encapsulation of 1,4,7,10-tetraazacyclododecane (cyclen) within silica nanoparticles using the Stöber process was studied. In the presence of cyclen and tetraethoxysilane (TEOS), silica particles exhibiting an unusual core-shell structure were obtained. On then basis of TEM, DLS, and NMR data, we suggest that the particle core is constituted of hybrid primary nanoparticles resulting from cyclen-silica interactions, whereas the shell formation results from further condensation of unreacted silica precursors. Control experiments performed with the zinc-cyclen complex and ammonia addition suggest that cyclen-TEOS interactions arise from the activation of the silicon alkoxide hydrolysis with the polyazamacrocycle amine groups. These data are discussed in the context of silica biomineralization mechanisms, where polyamine/silica interactions have been shown to play a major role. Moreover, the possibility to control the size and the structure of these nanoparticles makes them promising materials for pharmaceutical applications.
authors.affiliation: Laboratoire de Chimie de la Matière Condensée de Paris, Université Pierre et Marie Curie, Paris 6, CNRS, Paris cedex 05, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Masse
authors.forename: Guillaume
authors.initials: G
authors.lastname: Laurent
authors.forename: Françoise
authors.initials: F
authors.lastname: Chuburu
authors.forename: Cyril
authors.initials: C
authors.lastname: Cadiou
authors.forename: Isabelle
authors.initials: I
authors.lastname: Déchamps
authors.forename: Thibaud
authors.initials: T
authors.lastname: Coradin
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D008024:Ligands; D047028:Macrocyclic Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D001372:Aza Compounds; D008024:Ligands; D047028:Macrocyclic Compounds; D012822:Silicon Dioxide