Magnetic-fluorescent nanohybrids of carbon nanotubes coated with Eu, Gd co-doped LaF3 as a multimodal imaging probe.

Multifunctional magnetic-fluorescent nanohybrids were successfully fabricated by a facile layer-by-layer (LBL) self-assembly of in situ generated Eu, Gd co-doped LaF(3) nanocrystals (LaF(3):Eu:Gd) on the surface of multi-walled carbon nanotubes (MWNTs). Photoluminescence (PL) quenching occurred when LaF(3):Eu:Gd nanoparticles were directly coated on the surface of MWNTs. By growth of a SiO(2) shell spacer between MWNTs and LaF(3):Eu:Gd nanocrystals, we circumvented the PL quenching and achieved the magnetic-fluorescent MWNTs. Moreover, the nanohybrids showed powerful T(1) and T(2)-weighted magnetic resonance imaging (MRI) signal in water and could be used as MRI contrast agents. As a result, the nanohybrids can be expected to act as a promising multimodal MRI/optical imaging probe.