Ln3+ DOPED UPCONVERSION NANOPARTICLES FOR POTENTIAL DUAL MODAL BIO-IMAGING APPLICATION.

Bimodal bioimaging probes have raised wide concern in recent years for remedying shortcomings inherent to one given imaging technology. Rare-earth upconversion nanoparticles (UCNPs) which can absorb low-energy photons and emit high energy photons have attracted great interest not only because of their unique application in upconversion luminescence imaging, but also because they can generate visible emission by near-infrared radiation (NIR) excitation. Here we have synthesized PEI capped Ln3+ doped NaGdF4 UCNPs in a one-pot facile hydrothermal method in order to meet the demand for upconversion luminescence (UCL) and magnetic resonance imaging (MRI) simultaneously. PEI used here endows these NPs with good water solubility and biocompatibility. The properties of the nanoparticles were confirmed by transmission electron microscopy, X-ray powder diffraction, Fourier transform-infrared, and upconversion luminescence spectra and magnetism. Further biocompatibility test has also been investigated. The results indicate that our synthesized nanoparticles have potential application in bio-imaging probes combining UCL and MRI modal imaging together. [ABSTRACT FROM AUTHOR]