# Investigation of Uranium (VI) Speciation during Bone Formation Using ICP-MS

R. Laoufi¹* ; T. Gritsaenko² ; G. Carle² ; S. Santucci² ; A. Hagège¹

¹ Université Claude Bernard Lyon 1, CNRS, Institut des Sciences Analytiques - UMR 5280, 69100 Villeurbanne, France, ² Université Côte d'Azur, CEA, Institut Frédéric Joliot, TIRO-MATOs - UMR E4320, 06107 Nice, France
* rami.laoufi@isa-lyon.fr

Uranium, as a trace metal naturally present in the environment, is extensively used, particularly in industrial and military sectors, leading to its redistribution in the environment and an increased risk of exposure. Beyond its radioactivity, uranium also exhibits significant chemical toxicity. The controversy surrounding the use of depleted uranium has highlighted a significant lack of data on its chemical toxicity and its effects on the human body [1], emphasizing the need to intensify research in this area.

Bone is a primary site of uranium accumulation [2]. Despite numerous studies on the toxicological mechanisms of U (VI), our understanding remains incomplete, particularly regarding low-dose exposure (chronic toxicity). It is clear that U (VI) toxicity is influenced by its speciation and interactions with various ligands [3, 4]. Many of these complexes are thought to be labile, meaning they rapidly exchange ligands in solution. This presents an additional challenge in unraveling uranium speciation.

We have developed a method combining Taylor Dispersion Analysis (TDA) with Inductively Coupled Plasma Mass Spectrometry (ICP-MS), allowing us to maintain near-equilibrium conditions. This approach enables us to track both labile and inert U (VI) complexes by examining U (VI) distribution in culture medium as a function of cellular activity. This was achieved using a 3D biomimetic bone model [5] and analyzing the culture supernatants under different conditions and exposure times, along with the cellular extracts collected at the end of the exposure period.

Additionally, these samples were analyzed via CE-ICP-MS for enhanced resolution of stable complexes. These combined experimental methods provide new insights into U (VI) speciation during bone formation.

<figure><img src="image_1.png" /><figcaption>**Figure 1.** Workflow for Studying Uranium Speciation in Bone Formation Using TDA-ICP-MS and CE-ICP-MS</figcaption></figure>

## References

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[5] L. Hurault, *et al*. *Toxicol. Sci.* **2019**, *170*, 199-209.