GdVO4:Eu3+,Bi3+ Nanoparticles as a Contrast Agent for MRI and Luminescence Bioimaging

With the development of multifunctional imaging, gadolinium (Gd)-bearing inorganic nanoparticles (NPs), which were doped with trivalent lanthanide (Ln 3+ ), have been applied in magnetic resonance imaging (MRI) and optical imaging owing to their high payload of Gd 3+ ions and specific optical characteristics. In this study, we chose GdVO 4 codoped with Eu 3+ and Bi 3+ as the host material to generate a highly efficient contrast agent (CA) for MRI and long-term luminescence imaging. The new CA emits strong and stable luminescence because of its strong characteristic emissions, resulting from the energy-transfer process from the vanadate groups (VO 4 3- ) to the Eu 3+ and Bi 3+ dopants. Additionally, these NPs provided conspicuous T 1 and T 2 relaxation time-shortening characteristics, which result in MRI enhancement. GdVO 4 :Eu 3+ ,Bi 3+ NPs were tested on liver tumor-bearing nude mice, and showed improved liver tumor contrast in T 2 -weighted MR images ( T 2 WI). The dual-modal imaging probe exhibited no cytotoxicity or organ toxicity, reflecting its excellent biocompatibility. Thus, GdVO 4 :Eu 3+ ,Bi 3+ has the potential to be used for bioassays in vitro and liver tumor targeting in vivo . The results reveal the great promise of using the designed GdVO 4 :Eu 3+ ,Bi 3+ NPs as luminescent and MRI dual-mode bioprobes for clinical bioimaging applications.