Nanoparticles lanthanide-based

Hybrid materials have obtained a large interest in nanomaterials research and, recently, lanthanide-based materials have been combined with magnetic and metal nanomaterials in order to construct nanoparticles with advanced features... 

Meltzer et al. (2001) showed direct evidence for long-range interactions between lanthanide impurity ions in embedded nanocrystals with the TLS s of the matrix based on hole burning data. The samples were prepared as follows monoclinic 23 run Y2C>3 0.1% Eu3+ nanocrystals, produced by condensation after laser evaporation, were dispersed in a siloxane polymer. Fig. 13 shows the temperature dependence of the width of spectral holes (khb), which were burned in the 5Do <- 7Fo transition of Eu3+ ions located on the c sites (582.8 nm)innanociys-tals embedded in polymer, in comparison with the case of the free, as-prepared nanocrystals having the same size. The embedded nanocrystals exhibit a drastic increase in hole width and a very different power-law behavior for the temperature dependence of the hole widths relative to similar isolated nanoparticles. The 7 3 temperature dependence of the hole width... 

Lamellar nanohybrids composed of Ln203 layers regularly separated from each other by organic layers of intercalated benzoate molecules can be obtained by a one-pot procedure (Karmaoui et al., 2006), the benzyl alcohol route. Lanthanide isopropoxides are simply dissolved in benzyl alcohol and reacted at high temperature (250-300 °C), resulting in the isolation of nanoparticles of 50-nm mean size. Eu -doped nanohybrids have better radiance characteristics than the standard phosphor Y203 Eu while both yttrium- and gadolinium-based nanomaterials doped with Nd display intense NIR luminescence, with a Nd( F3/2) lifetime of 49 ps in the case of the yttrium nanohybrid (Sa Ferreira et al., 2006). 

Nishiyabu et al." describe nanoparticles based on supramolecular networks of nucleotides and lanthanides. Multimodahty is achieved in this system by enclosing entities such as dyes, enzymes, and gold nanoparticles. Gold nanoparticles were formed capped with 5 -GMP, and then mixed in buffer with GdCla to generate a supramolecular network on the particle surface. The nucleotide/lanthanide nanoparticles were reported to have longitudinal relaxivities (ri) of 12.5 s mM. Much remains to be determined about the utility of these constructs for clinical applications. 

---