Nanoparticelle attivate con ioni lantanidi per imaging multimodale

Oxide and fluoride based compounds doped with luminescent lanthanide ions are nowadays interesting materials which can be employed in many technological applications, for instance as optical probes in biomedicine. In this research project we have investigated zirconium oxide (ZrO2) and fluoride (CaF2, SrF2, NaYF4) nanocrystalline materials doped with luminescent lanthanide ions (Eu3+, Tb3+, Er3+, Tm3+, Ho3+, Yb3+). The obtained ZrO2 nanoparticles (NPs) have been are prepared by a hydrothermal technique using oleate ions as capping agents. The prepared materials have a monoclinic or tetragonal structure, with an average particle size around 4 nanometer. The Eu3+ and Tb3+ doped samples show a strong Stokes emission in the visible region upon excitation with UV light. The obtained NPs are very well dispersable in organic solvents as toluene. Lanthanide doped CaF2 and SrF2 NPs are also obtained by hydrothermal synthesis, using oleate or citrate ions as capping agents. The NPs capped with oleate or citrate ions are dispersable in organic solvents or water, respectively. The NPs have a cubic phase with an average particle size of 10 nm. The obtained NPs show a strong emission in the visible and NIR region upon excitation at 980 nm (upconversion emission). Some samples have been also doped with gadolinium ions and preliminary results show that the NPs can be used as both optical probes and MRI contrast agents, indicating that they can be excellent candidates for multimodal imaging.