Ionic Liquid Mediated Synthesis and Surface Modification of Multifunctional Mesoporous Eu:GdF₃ Nanoparticles for Biomedical Applications

A procedure for the synthesis of multifunctional europium­(III)-doped gadolinium­(III) fluoride (Eu:GdF₃) nanoparticles (∼85 nm) with quasispherical shape by precipitation at 120 °C from diethylene glycol solutions containing lanthanide chlorides and an ionic liquid (1-Butyl, 2-methylimidazolium tetrafluoroborate) as fluoride source has been developed. These nanoparticles were polycrystalline and crystallized into a hexagonal structure, which is unusual for GdF₃. They were also mesoporous (pore size = 3.5 Å), having a rather high BET surface area (75 m² g^–1). The luminescent and magnetic (relaxivity) properties of the Eu:GdF₃ nanoparticles have been also evaluated in order to assess their potentiality as “in vitro” optical biolabels and contrast agent for magnetic resonance imaging. Finally, a procedure for their functionalization with aspartic-dextran polymers is also reported. The functionalized Eu:GdF₃ nanoparticles presented negligible toxicity for Vero cells, which make them suitable for biotecnological applications

Microwave-Assisted Synthesis and Luminescence of Mesoporous RE-Doped YPO₄ (RE = Eu, Ce, Tb, and Ce + Tb) Nanophosphors with Lenticular Shape

Mesoporous tetragonal RE:YPO₄ nanophosphors (RE = Eu, Ce, Tb, and Ce + Tb) with a lenticular morphology, narrow size distribution, and high surface area have been prepared by an homogeneous precipitation procedure consisting of aging, at low temperature (80–120 °C) in a microwave oven, ethylene glycol solutions containing only yttrium acetylacetonate and phosphoric acid. This synthesis method involves important advantages such as its simplicity, rapidness (reaction time = 7 min), and high reaction yields. The mechanism of nanoparticle growth has been also addressed finding that the lenticular nanoparticles are formed through an ordered aggregation of smaller entities, which explains their porosity. In all cases, the doping levels were systematically varied in order to optimize the nanophosphors luminescence. All optimum nanophosphors presented a high luminescence quantum yield (QY). In particular, for the Eu and Tb doped systems, the obtained QY values (60% for Eu and 80% for Tb) were the highest so far reported for this kind of nanomaterial. The morphological, microstructural, and luminescent properties of these nanophosphors and their dispersibility in water make them suitable for biomedical applications

Synthesis and properties of multifunctional tetragonal Eu:GdPO4 nanocubes for optical and magnetic resonance imaging applications

A simple and fast (7 min) procedure for synthesis of gadolinium phosphate nanocubes (edge = 75 nm) based on the microwave-assisted heating at 120 C of gadolinium acetylacetonate and phosphoric acid solutions in buthylene glycol is reported. These nanocubes were highly crystalline and crystallized into a tetragonal structure, which has not been ever reported for pure gadolinium phosphate. Determination of such crystal structure has been carried out here for the first time in the literature by means of powder X-ray diffraction. The developed synthesis procedure was also successful for preparation of multifunctional europium(III)-doped the gadolinium phosphate nanocubes, which were nontoxic for cells and exhibited strong red luminescence under UV illumination and high transverse relaxivity (r2) values. These properties confer them potential applications as biolabels for in vitro optical imaging and as negative contrast agent for magnetic resonance imaging. © 2012 American Chemical Society.Peer Reviewe