title: High-relaxivity and luminescent silica nanoparticles as multimodal agents for molecular imaging.
abstract: The design and synthesis of a new bimodal contrast agent for magnetic resonance imaging and optical imaging is reported. Tunable-sized silica nanoparticles were synthesized by a microemulsion-mediated pathway and used as carriers for paramagnetic and luminescent probes. The near-infrared luminescent agent was a ruthenium complex that was directly entrapped in the silica shell to provide photoluminescence enhancement and to make it highly photostable as it was protected from the surrounding environment. The paramagnetic activity came from a Gd-DTPA derivative that was grafted on the silica surface. NMRD profiles showed a strong relaxivity enhancement (increase of 432% in the r1 value at 20 MHz) when the paramagnetic complex was grafted at the nanoparticle surface, because of a reduction of its mobility. Polyethylene glycol was also grafted at the nanoparticle surface to enhance the nanoparticle residence time in the bloodstream. A thorough characterization of the material confirmed its potential as a very effective bimodal contrast agent.
authors: Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, Mons (BE), Belgium.
authors: Estelle
authors: E
authors: Lipani
authors: Sophie
authors: S
authors: Laurent
authors: Mathieu
authors: M
authors: Surin
authors: Luce
authors: L
authors: Vander Elst
authors: Philippe
authors: P
authors: Leclère
authors: Robert N
authors: RN
authors: Muller
mesh_terms: D003287:Contrast Media / Q000737:chemistry*; D057054:Molecular Imaging / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D011092:Polyethylene Glycols; D012822:Silicon Dioxide