Dataset Information

Controllable sites and high-capacity immobilization of uranium in Nd₂Zr₂O₇ pyrochlore.

ABSTRACT: As potential nuclear waste host matrices, two series of uranium-doped Nd₂Zr₂O₇ nanoparticles were successfully synthesized using an optimized molten salt method in an air atmosphere. Our combined X-ray diffraction, Raman and X-ray absorption fine-structure (XAFS) spectroscopy studies reveal that uranium ions can precisely substitute the Nd site to form an Nd_2-xU_xZr₂O_7+δ (0 ≤ x ≤ 0.2) system and the Zr site to form an Nd₂Zr_2-yU_yO_7+δ (0 ≤ y ≤ 0.4) system without any impurity phase. With increasing U concentration, there is a phase transition from pyrochlore (Fd3m) to defect fluorite (Fm3m) structures in both series of U-doped Nd₂Zr₂O₇. The XAFS analysis indicates that uranium exists in the form of high-valent U⁶⁺ in all samples. To balance the extra charge for substituting Nd³⁺ or Zr⁴⁺ by U⁶⁺, additional oxygen is introduced accompanied by a large structural distortion; however, the Nd₂Zr_1.6U_0.4O_7+δ sample with high U loading (20 mol%) still maintains a regular fluorite structure, indicating the good solubility of the Nd₂Zr₂O₇ host for uranium. This study is, to the best of our knowledge, the first systematic study on U-incorporated Nd₂Zr₂O₇ synthesized via the molten salt method and provides convincing evidence for the feasibility of accurately immobilizing U at specific sites.

SUBMITTER: Sun J

PROVIDER: S-EPMC8733979 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundIn vivo monitoring of cell biodistribution using positron emission tomography (PET) provides a quantitative non-invasive method to further optimize cell therapies and related new developments in the field. Our group has earlier optimized and evaluated the in vitro properties of two radiotracers,[89Zr]Zr-(oxinate)4 and [89Zr]Zr-DFO-NCS, for the radiolabelling of different cell types. Here, we performed a microPET study to assess the in vivo biodistribution of cells in rats using these two radiotracers. Human decidual stromal cells (hDSC) and rat macrophages (rMac) were radiolabelled with [89Zr]Zr-(oxinate)4 or [89Zr]Zr-DFO-NCS. Rats were intravenously injected with radiolabelled cells, and the in vivo biodistribution was monitored with microPET/CT imaging for up to day 7. Organ uptake was evaluated and presented as a percentage of injected activity per gram tissue (%IA/g) and total absorbed organ doses (mSv/MBq).ResultsThe biodistribution in vivo showed an immediate uptake in the lungs. Thereafter, [89Zr]Zr-(oxinate)4 labelled cells migrated to the liver, while the signal from [89Zr]Zr-DFO-NCS labelled cells lingered in the lungs. The differences in the in vivo behaviour for the same cell type appeared related to the radiotracer labelling. After 24 h, [89Zr]Zr-(oxinate)4 labelled cells had over 70% higher liver uptake for both hDSC and rMac compared to [89Zr]Zr-DFO-NCS labelled cells, whereas [89Zr]Zr-DFO-NCS labelled cells showed over 60% higher uptake in the lungs compared to [89Zr]Zr-(oxinate)4 labelled cells. This difference in both lung and liver uptake continued until day 7. Dosimetry calculations showed a higher effective dose (mSv/MBq) for [89Zr]Zr-DFO-NCS compared to [89Zr]Zr-(oxinate)4, for both cell types. Although the bone uptake was higher for [89Zr]Zr-(oxinate)4 labelled cells, the prolonged uptake in the lungs contributed to a significant crossfire to bone marrow resulting in a higher bone dose.ConclusionThe [89Zr]Zr-DFO-NCS labelled cells suggest a prolonged accumulation in the lungs, while [89Zr]Zr-(oxinate)4 suggests quicker clearance of the lungs followed by accumulation in the liver. Accumulation of radiolabelled cells in the liver corresponds to other cell-tracking methods. Further studies are required to determine the actual location of the [89Zr]Zr-DFO-NCS labelled cell.

Dataset Information

Controllable sites and high-capacity immobilization of uranium in Nd₂Zr₂O₇ pyrochlore.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Controllable sites and high-capacity immobilization of uranium in Nd2Zr2O7 pyrochlore.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Controllable sites and high-capacity immobilization of uranium in Nd₂Zr₂O₇ pyrochlore.