Facile synthesis of lanthanide nanoparticles with paramagnetic, down- and up-conversion properties.

Lanthanide materials play an important role in biomedical researches, among which paramagnetic, down- and up-conversion lanthanide nanoparticles are of particular interest. However, little effort has been made to develop versatile lanthanide nanoparticles with these properties combined in a single particle. Herein, we present a facile strategy to make multifunctional lanthanide nanoparticles by doping sensitized lanthanide complexes into porous silica coated on up-conversion NaYF(4) nanocrystals. The nanoparticles not only show strong down- and up-conversion fluorescence but also exhibit high magnetic resonance properties.