L’exposition cutanée aux nanoparticules métalliques: Développement d’un modèle expérimental pour l’étude de la décontamination de la peau après une exposition aux nanoparticules métalliques

National audienceBien que les possibilités de pénétration cutanée des nanoparticules jusqu’à la circulation systémique semblent faibles sur peau saine, les plus petites nanoparticules pourraient franchir la peau via les follicules pileux, les glandes sudoripares ou voie intercellulaire et constituer des réservoirs au niveau de la peau. Dans le cas des nanoparticules métalliques , leur dissolution pourrait conduire à des effets locaux de type dermatite ou sensibilisation liés aux ions métalliques libérés. Une des questions importantes en cas de contamination accidentelle de la peau est de savoir comment la nettoyer efficacement. L’objectif de cette étude de faisabilité est de développer un modèle expérimental adapté pour l’étude de la décontamination de la peau à des nanoparticules de type métallique : argent (Ag) et dioxyde de titane (TiO2). Le développement d’une méthode répond non seulement aux attentes concrètes des médecins du travail, mais il pourra aussi être extrapolé à la population générale

Comments on “A Simple, Rapid, Comparative Evaluation of Multiple Products for Decontamination of Actinide-contaminated Rat Skin Ex Vivo “

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OPTIMIZATION OF 226RA URINE EXTRACTION FOR INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY (ICP-MS) ANALYSIS

International audienceRadium 226 has been identified as a highly radiotoxic radionuclide with a high potential of malevolence uses. In radiological emergency situations and for medical monitoring of nuclear workers, urine analysis is the more convenient to estimate the effective dose. A lot of methods for radium analysis in urine have been described in the literature, differing from the time of preparation and analysis and detection limit. Based on the protocol defined by Cozzella and al. in 2011(1) who used the Dowex® 50W-X8 resin, the urine extraction procedure of 226Ra was optimized for ICP-MS analysis in order to realize the extraction as fast as possible with a detection limit adapted to highlight an effective dose of 1 mSv. Besides this optimization, the contribution of polyatomic interferences as 88Sr138Ba, very common interference for 226Ra measurement by ICP-MS, was determined and taken into account in our results. First results showed that the radium extraction on Dowex® 50W-X8 resin was not complete in our experimental conditions. Two hypothesis could explain these results: the saturation of the resin or the acid conditions that are not optimal for the radium extraction on Dowex® 50W-X8 resin. To improve these results, some experiments were performed:-Determination of the distribution coefficient of 226Ra on Dowex® 50W-X8 to adapt the preconditionement of the resin and optimize the radium elution step,-Determination of the maximal capacity of Dowex® 50W-X8 resin for radium extraction,-Optimization of the procedure with a mineralization step after the co-precipitation of radium in order to eliminate the organic matter which prevent the radium extraction on the resin.Besides that, two other resins were also tested: -The Analig® Ra-01, a specific resin for radium, that has been applied by Verlinde et al. for water analysis (2),-The calix-[6]-arene based column that has been developed for actinides in urine by Bouvier-Capely et al.(1)Cozzella M.L. et al. Determination of 226Ra in urine samples by Q-ICP-MS : a method for routine analyses. Radiat Meas. 2011 ; 46 : 109-111.(2)Verlinde M. and al. A new protocol for 226Ra separation and preconcentration in natural water sample using molecular recognition technology for ICP-MS analysis. J Environ Radioact. 2019 ; 202 : 1-7.(3)Bouvier-Capely et al. Operational protocol for detection of contamination by actinides U, Pu and Am in urine using Calixarene columns : from mineralization to ICP-MS measurement. Am J Anal Chem. 2017 ; 8 : 317-333

Development of a SIMS compatible internal standard spiked resin for quantitative bio-imaging of biological samples by laser ablation ICP-MS: an application to uranium contaminated kidney samples

International audienceIn the last decade, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has evolved as an efficient analytical technique for in situ quantitative analysis of solid samples with micrometer-scale spatial resolution and low limits of detection. However, the progress in biological or medical science application is still determined by the availability of calibration standards and appropriate internal standards (IS) to compensate signal variation during laser beam-sample interaction, transportation of the aerosol and instrumental drifts during analysis [1]. In addition, it would be desirable that both samples and calibrations standards could be shared by different imaging techniques. Therefore, the aim of this work is to find a sample/standard preparation methodology compatible with laser ablation and Secondary-Ion Mass Spectrometry (SIMS) analyses for a complementary analysis of uranium distribution in kidney with both techniques. On the one hand, in-house solid standards were prepared from uranium spiked kidney homogenate and their homogeneity was assessed by isotope dilution ICPMS after acid digestion. On the other hand, a novel approach based on IS doped resin was carried out in order to incorporate a more feasible internal standard than 13C. Indeed, carbon feasibility for quantitative LA-ICPMS imaging has been queried recently [2-4]. Therefore, thulium spiked pure EPON resin was synthetized and employed to embed dehydrated samples and doped homogenates based on the chemical sample preparation protocol of biological samples for SIMS analysis [5, 6]. Nevertheless, the chemical dehydration protocol was adapted to the viscous and liquid state of the homogenates. In parallel, with the objective of determining the real need of producing organ homogenates (laborious task and requires the access to animal facilities), uranyl nitrate (powder) spiked resin was also tested in order to compare slopes after laser ablation with those obtained with organ homogenates. Then, serial thin and ultra-thin sections were cut with microtome and the homogeneity of internal standard was evaluated by randomly analysing small selected areas by LA-ICP-MS and SIMS. Laser ablation conditions were optimized to achieve complete sample consumption of the tissue whilst minimizing the penetration into the glass slide. The advantages of this new methodology are 1) the addition of a suitable internal standard to both matrix-matched standards and biological samples without altering their original uranium distribution, 2) an appropriate sample preparation compatible with several imaging techniques (SIMS, TEM, LA), 3) ease to prepare and 4) room temperature storage as a solid material which would facilitate its transport. We believe that this methodology will positively contribute to the collaboration among bio-imaging techniques users

OPTIMIZATION OF 226RA URINE EXTRACTION FOR INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY (ICP-MS) ANALYSIS

International audienceRadium 226 has been identified as a highly radiotoxic radionuclide with a high potential of malevolence uses. In radiological emergency situations and for medical monitoring of nuclear workers, urine analysis is the more convenient to estimate the effective dose. A lot of methods for radium analysis in urine have been described in the literature, differing from the time of preparation and analysis and detection limit. Based on the protocol defined by Cozzella and al. in 2011(1) who used the Dowex® 50W-X8 resin, the urine extraction procedure of 226Ra was optimized for ICP-MS analysis in order to realize the extraction as fast as possible with a detection limit adapted to highlight an effective dose of 1 mSv. Besides this optimization, the contribution of polyatomic interferences as 88Sr138Ba, very common interference for 226Ra measurement by ICP-MS, was determined and taken into account in our results. First results showed that the radium extraction on Dowex® 50W-X8 resin was not complete in our experimental conditions. Two hypothesis could explain these results: the saturation of the resin or the acid conditions that are not optimal for the radium extraction on Dowex® 50W-X8 resin. To improve these results, some experiments were performed:-Determination of the distribution coefficient of 226Ra on Dowex® 50W-X8 to adapt the preconditionement of the resin and optimize the radium elution step,-Determination of the maximal capacity of Dowex® 50W-X8 resin for radium extraction,-Optimization of the procedure with a mineralization step after the co-precipitation of radium in order to eliminate the organic matter which prevent the radium extraction on the resin.Besides that, two other resins were also tested: -The Analig® Ra-01, a specific resin for radium, that has been applied by Verlinde et al. for water analysis (2),-The calix-[6]-arene based column that has been developed for actinides in urine by Bouvier-Capely et al.(1)Cozzella M.L. et al. Determination of 226Ra in urine samples by Q-ICP-MS : a method for routine analyses. Radiat Meas. 2011 ; 46 : 109-111.(2)Verlinde M. and al. A new protocol for 226Ra separation and preconcentration in natural water sample using molecular recognition technology for ICP-MS analysis. J Environ Radioact. 2019 ; 202 : 1-7.(3)Bouvier-Capely et al. Operational protocol for detection of contamination by actinides U, Pu and Am in urine using Calixarene columns : from mineralization to ICP-MS measurement. Am J Anal Chem. 2017 ; 8 : 317-333

OPTIMIZATION OF 226RA URINE EXTRACTION FOR INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY (ICP-MS) ANALYSIS

International audienceRadium 226 has been identified as a highly radiotoxic radionuclide with a high potential of malevolence uses. In radiological emergency situations and for medical monitoring of nuclear workers, urine analysis is the more convenient to estimate the effective dose. A lot of methods for radium analysis in urine have been described in the literature, differing from the time of preparation and analysis and detection limit. Based on the protocol defined by Cozzella and al. in 2011(1) who used the Dowex® 50W-X8 resin, the urine extraction procedure of 226Ra was optimized for ICP-MS analysis in order to realize the extraction as fast as possible with a detection limit adapted to highlight an effective dose of 1 mSv. Besides this optimization, the contribution of polyatomic interferences as 88Sr138Ba, very common interference for 226Ra measurement by ICP-MS, was determined and taken into account in our results. First results showed that the radium extraction on Dowex® 50W-X8 resin was not complete in our experimental conditions. Two hypothesis could explain these results: the saturation of the resin or the acid conditions that are not optimal for the radium extraction on Dowex® 50W-X8 resin. To improve these results, some experiments were performed:-Determination of the distribution coefficient of 226Ra on Dowex® 50W-X8 to adapt the preconditionement of the resin and optimize the radium elution step,-Determination of the maximal capacity of Dowex® 50W-X8 resin for radium extraction,-Optimization of the procedure with a mineralization step after the co-precipitation of radium in order to eliminate the organic matter which prevent the radium extraction on the resin.Besides that, two other resins were also tested: -The Analig® Ra-01, a specific resin for radium, that has been applied by Verlinde et al. for water analysis (2),-The calix-[6]-arene based column that has been developed for actinides in urine by Bouvier-Capely et al.(1)Cozzella M.L. et al. Determination of 226Ra in urine samples by Q-ICP-MS : a method for routine analyses. Radiat Meas. 2011 ; 46 : 109-111.(2)Verlinde M. and al. A new protocol for 226Ra separation and preconcentration in natural water sample using molecular recognition technology for ICP-MS analysis. J Environ Radioact. 2019 ; 202 : 1-7.(3)Bouvier-Capely et al. Operational protocol for detection of contamination by actinides U, Pu and Am in urine using Calixarene columns : from mineralization to ICP-MS measurement. Am J Anal Chem. 2017 ; 8 : 317-333

Study of the U/Am separation with supported calix[6]arene in the aim of urinary actinides analysis

The aim of this work is to propose an alternative radiochemical procedure for the analysis of U, Pu and Am in urine, which is one of the controls used to monitor workers exposed to risk of internal contamination with actinides. Previous studies have demonstrated the extraction efficiency of these molecules towards uranium and plutonium, the affinity of calix[6]arenes bearing hydroxamic acid groups (LHH3) and carboxylic groups (LC H3) towards americium were studied in this paper by solvent extraction. The results showed that LHH3 and LCH3 have a very good affinity for americium and enhance the possibility of separating Pu from U and Am. Experiments were performed to perfect the separation of U/Am. The immobilisation of these calixarenes on polymer supports was also investigated for routine applications. Supported calixarenes LCH3 and LHH3 presented the same performances as those obtained in a liquid-liquid system and, hence, are a promising system for the analysis of actinides. These molecules and their uses have been protected (patent pending). © The Author 2007. Published by Oxford University Press. All rights reserved

Solvent extraction of U(VI) by calix[6]arenes

This paper focuses on the solvent extraction of U(VI) traces by 1,3,5-OMe-2,4,6-OCH2CONHOH-p-tert-butylcalix[6]arene (LH3). The global extraction equation of U(VI) has been established. The complex formed in the organic phase is (UO2) (LH) with an apparent extraction constant equal to 7.1×10-5 M(I =0.04 M). Distribution data show that LH3 efficiently extracts U(VI) from NaNO3 media at pH 5 and that the stripping of U(VI) can be achieved in nitric acid solutions. Finally a comparison with previous results obtained with the 1,3,5-OMe-2,4,6-OCH2COOH-p-tert-butylcalix[6]arene (L′H3) shows that the hydroxamate groups are as efficient as the carboxylate ones for uranyl extraction. Copyright © Taylor & Francis Group, LLC

An alternative procedure for uranium analysis in drinking water using AQUALIX columns: Application to varied French bottled waters

The general population is chronically exposed to uranium (234U, 235U, and 238U) and polonium (210Po) mainly through day-to-day food and beverage intake. The measurement of these naturally-occurring radionuclides in drinking water is important to assess their health impact. In this work the applicability of calix[6]arene-derivatives columns for uranium analysis in drinking water was investigated. A simple and effective method was proposed on a specific column called AQUALIX, for the separation and preconcentration of U from drinking water. This procedure is suitable for routine analysis and the analysis time is considerably shortened (around 4 h) by combining the separation on AQUALIX with fast ICP-MS measurement. This new method was tested on different French bottled waters (still mineral water, sparkling mineral water, and spring water). Then, the case of simultaneous presence of uranium and polonium in water was considered due to interferences in alpha spectrometry measurement. A protocol was proposed using a first usual step of spontaneous deposition of polonium on silver disc in order to separate Po, followed by the uranium extraction on AQUALIX column before alpha spectrometry counting. © 2013 Elsevier B.V