GdVO(4):Eu(3+),Bi(3+) Nanoparticles as a Contrast Agent for MRI and Luminescence Bioimaging

[Image: see text] 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.