Search

Your search keyword '"MESH: Spectrometry, X-Ray Emission"' showing total 6 results
Start Over Descriptor "MESH: Spectrometry, X-Ray Emission"
6 results on '"MESH: Spectrometry, X-Ray Emission"'

1. Greigite nanocrystals produced by hyperthermophilic archaea of Thermococcales order

Author

Aurore Gorlas, Sukhvinder Gill, Pierre Jacquemot, François Guyot, Jean-Michel Guigner, Patrick Forterre, Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Biologie Cellulaire des Archées (ARCHEE), Département Microbiologie (Dpt Microbio), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Biologie Moléculaire du Gène chez les Extrêmophiles (BMGE), Institut Pasteur [Paris], Aurore Gorlas and Patrick Forterre were funded by the Agence Nationale de la Recherche, project Thermovésicules (ANR 12-BSV3-003-01). Patrick Forterre and Sukhvinder Gill were supported by the European Research council, project EVOMOBIL (FP/2007-2013) - ERC GrantAgreement no. 340440 to PF., ANR-12-BSV3-0023,THERMOVESICULES,Vésicules membranaires produites par des microbes hyperthermophiles: physiologie, toxicité, transferts de gènes et interactions avec des virus(2012), European Project: 340440,EC:FP7:ERC,ERC-2013-ADG,EVOMOBIL(2014), and Institut Pasteur [Paris] (IP)

Subjects
0301 basic medicine, MESH: Oxidation-Reduction, Hot Temperature, MICROBIO, DBG, [SDV]Life Sciences [q-bio], lcsh:Medicine, Marine and Aquatic Sciences, RBA, iron sulfides, Extreme environment, Electron Microscopy, mineralization, MESH: Ecosystem, ARCHEE, lcsh:Science, Microscopy, mechanisms, vesicles, MESH: Iron, Multidisciplinary, biology, Chemistry, MESH: Spectrometry, X-Ray Emission, minerals, Thermococcales, MESH: Hydrothermal Vents, MESH: Carbon Dioxide/chemistry, Physical Sciences, MESH: Microscopy, Electron, Transmission, Scanning Electron Microscopy, Cellular Structures and Organelles, Marine Geology, Oxidation-Reduction, Hydrothermal vent, Research Article, Chemical Elements, Greigite, life, Iron, growth, 030106 microbiology, oxidizing bacteria, Sulfides, MESH: Hot Temperature, Research and Analysis Methods, Hydrothermal circulation, Catalysis, Phosphates, 03 medical and health sciences, Extracellular polymeric substance, Hydrothermal Vents, Microscopy, Electron, Transmission, High Resolution Transmission Electron Microscopy, Ecosystem, lcsh:R, Chemical Compounds, Biology and Life Sciences, Spectrometry, X-Ray Emission, MESH: Sulfides, Cell Biology, Carbon Dioxide, sequence, biology.organism_classification, biomineralization, MESH: Catalysis, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, 030104 developmental biology, Chemical engineering, 13. Climate action, Earth Sciences, Nanoparticles, lcsh:Q, Transmission Electron Microscopy, Sulfur, MESH: Nanoparticles, MESH: Thermococcales, Biomineralization, Archaea
Abstract

WOS:000440778600056; International audience; Interactions between hyperthermophilic archaea and minerals occur in hydrothermal deep-ea vents, one of the most extreme environments for life on Earth. These interactions occur in the internal pores and at surfaces of active hydrothermal chimneys. In this study, we show that, at 85 degrees C, Thermococcales, the predominant hyperthermophilic microorganisms inhabiting hot parts of hydrothermal deep-sea vents, produce greigite nanocrystals (Fe3S4) on extracellular polymeric substances, and that an amorphous iron phosphate acts as a precursor phase. Greigite, although a minor component of chimneys, is a recognized catalyst for CO2 reduction thus implying that Thermococcales may influence the balance of CO2 in hydrothermal ecosystems. We propose that observation of greigite nanocrystals on extracellular polymeric substances could provide a signature of hyperthermophilic life in hydrothermal deep-sea vents.

Published
2018
Full Text
View/download PDF

2. Interplay between glutathione, Atx1 and copper: X-ray absorption spectroscopy determination of Cu(I) environment in an Atx1 dimer

Author

Christophe Den Auwer, Michel Ferrand, Elisabeth Mintz, Serge Crouzy, Roger Miras, Clara Fillaux, David Poger, Pascale Delangle, Laboratoire de Chimie et Biologie des Métaux (LCBM - UMR 5249), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Service de Chimie des Procédés de Séparation (SCPS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Reconnaissance Ionique et Chimie de Coordination (RICC), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG)

Subjects
Models, Molecular, MESH: Ions, Coordination sphere, MESH: Biological Transport, Dimer, Inorganic chemistry, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Biochemistry, Ion, Inorganic Chemistry, MESH: Cation Transport Proteins, 03 medical and health sciences, chemistry.chemical_compound, Molecule, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Cation Transport Proteins, 030304 developmental biology, Ions, MESH: Glutathione, 0303 health sciences, X-ray absorption spectroscopy, MESH: Protein Multimerization, Spectrometry, X-Ray Emission, Biological Transport, MESH: Spectrometry, X-Ray Emission, Glutathione, Sulfur, Copper, 3. Good health, 0104 chemical sciences, MESH: Copper, Crystallography, chemistry, Protein Multimerization, MESH: Molecular Chaperones, Absorption (chemistry), MESH: Models, Molecular, Molecular Chaperones
Abstract

X-ray absorption techniques have been used to characterise the primary coordination sphere of Cu(I) bound to glutathionate (GS−), to Atx1 and in Cu 2 I (GS−)2(Atx1)2, a complex recently proposed as the major form of Atx1 in the cytosol. In each complex, Cu(I) was shown to be triply coordinated. When only glutathione is provided, each Cu(I) is triply coordinated by sulphur atoms in the binuclear complex CuI 2(GS−)5, involving bridging and terminal thiolates. In the presence of Atx1 and excess of glutathione, under conditions where CuI 2(GS−)2(Atx1)2 is formed, each Cu(I) is triply coordinated by sulphur atoms. Given these constraints, there are two different ways for Cu(I) to bridge the Atx1 dimer: either both Cu(I) ions contribute to bridging the dimer, or only one Cu(I) ion is responsible for bridging, the other one being coordinated to two glutathione molecules. These two models are discussed as regards Cu(I) transfer to Ccc2a.

Published
2008
Full Text
View/download PDF

3. X-ray spectroscopy and X-ray diffraction at wavelengths near theK-absorption edge of phosphorus

Author

Corinne Mas, Gérard Brandolin, J. Vicat, Richard Kahn, Heinrich Stuhrmann, Hugues Nury, Valérie Biou, Eva Pebay-Peyroula, Jean Marie Bois, Lionel Nauton, Peter Bösecke, Laboratoire d'enzymologie et biochimie structurales (LEBS), Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mathématiques de Reims (LMR), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Biochimie et biophysique des systèmes intégrés (BBSI), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF), Institut de biologie structurale (IBS - UMR 5075 ), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Halobacterium, Diffraction, Nuclear and High Energy Physics, Absorption spectroscopy, Protein Conformation, Carbon-Oxygen Lyases, Neutron diffraction, Molecular Conformation, Analytical chemistry, MESH: Equipment Failure Analysis, 01 natural sciences, MESH: Carbon-Oxygen Lyases, Crystal, 03 medical and health sciences, MESH: Protein Conformation, Purple Membrane, X-Ray Diffraction, 0103 physical sciences, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM], MESH: Phosphorus, Instrumentation, 030304 developmental biology, 010302 applied physics, MESH: Molecular Conformation, 0303 health sciences, X-ray spectroscopy, Radiation, Chemistry, MESH: X-Ray Diffraction, Spectrometry, X-Ray Emission, MESH: Spectrometry, X-Ray Emission, Phosphorus, Equipment Design, MESH: Purple Membrane, Equipment Failure Analysis, Wavelength, Crystallography, Absorption edge, X-ray crystallography, MESH: Halobacterium, MESH: Mitochondrial ADP, ATP Translocases, Mitochondrial ADP, ATP Translocases, MESH: Equipment Design
Abstract

International audience; Phosphorus is an abundant element in living organisms. It is traceable by its X-ray absorption spectrum which shows a strong white line at its K-edge, comparable with that observed for the L(III) edges of rare earth ions. With purple membrane, the variation of the imaginary part of the anomalous dispersion of phosphorus is found to be close to 20 anomalous electron units. Anomalous diffraction experiments at wavelengths near the K-absorption edge of phosphorus confirm this result. The spatial distribution of lipids derived from anomalous diffraction agrees with earlier results from neutron diffraction. Test experiments on single crystals of the carrier protein using 5.76 A photons gave a first low-resolution diffraction pattern. Various techniques of crystal mounting were attempted. In addition, fluorescence measurements on a solution of threonine synthase appear to hint at a change of the phosphate environment of the cofactor upon activator binding.

Published
2005
Full Text
View/download PDF

4. Dendrochemical patterns of calcium, zinc, and potassium related to internal factors detected by energy dispersive X-ray fluorescence (EDXRF)

Author

Håkan Grudd, Don A. Vroblesky, Michel Chalot, Jean Christophe Balouet, François Beaujard, Kevin T. Smith, Walter C. Shortle, Joel G. Burken, United States Department of Agriculture, International Environmental, Université de Franche-Comté (UFC), Université de Lorraine (UL), Laboratoire de Physique et Physiologie Intégratives de l'Arbre Fruitier et Forestier (PIAF), Institut National de la Recherche Agronomique (INRA)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP), Bolin Centre for Climate Research, Stockholm University, United States Geological Survey [Reston] (USGS), Missouri University of Science and Technology (Missouri S&T), University of Missouri System, Laboratoire Chrono-environnement - UFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Université de Franche-Comté ( UFC ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Physique et Physiologie Intégratives de l'Arbre Fruitier et Forestier ( PIAF ), Institut National de la Recherche Agronomique ( INRA ) -Université Blaise Pascal - Clermont-Ferrand 2 ( UBP ), Laboratoire Chrono-environnement (UMR 6249) (LCE), and Université Bourgogne Franche-Comté [COMUE] (UBFC)

Subjects
bois, Wood calcium, Health, Toxicology and Mutagenesis, Potassium, [SDV]Life Sciences [q-bio], Cation distribution, MESH: Zinc, Annual growth %, Trees, MESH : Trees, MESH : Environmental Monitoring, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, MESH: Spectrometry, X-Ray Emission, General Medicine, Contamination, Pollution, Zinc, Metals, Environmental chemistry, MESH: Calcium, Dendrochemistry, Wood potassium, MESH: Environmental Monitoring, Environmental Monitoring, Environmental Engineering, chemistry.chemical_element, X-ray fluorescence, Calcium, dendrochimie, [ SDV.EE ] Life Sciences [q-bio]/Ecology, environment, MESH : Spectrometry, X-Ray Emission, Environmental Chemistry, MESH : Calcium, MESH: Metals, MESH : Metals, Public Health, Environmental and Occupational Health, Spectrometry, X-Ray Emission, General Chemistry, MESH : Zinc, Highly sensitive, MESH: Trees, MESH : Potassium, chemistry, 13. Climate action, MESH: Potassium, Biomineralization
Abstract

International audience; Energy dispersive X-ray fluorescence (EDXRF) provides highly sensitive and precise spatial resolution of cation content in individual annual growth rings in trees. The sensitivity and precision have prompted successful applications to forensic dendrochemistry and the timing of environmental releases of contaminants. These applications have highlighted the need to distinguish dendrochemical effects of internal processes from environmental contamination. Calcium, potassium, and zinc are three marker cations that illustrate the influence of these processes. We found changes in cation chemistry in tree rings potentially due to biomineralization, development of cracks or checks, heartwood/sapwood differentiation, intra-annual processes, and compartmentalization of infection. Distinguishing internal from external processes that affect dendrochemistry will enhance the value of EDXRF for both physiological and forensic investigations.

Published
2014
Full Text
View/download PDF

5. Overexpressed or intraperitoneally injected human transferrin prevents photoreceptor degeneration in rd10 mice

Author

Picard, Émilie, Jonet, Laurent, Sergeant, Claire, Vesvres, Marie-Hélène, Behar-Cohen, Francine, Courtois, Yves, Jeanny, Jean-Claude, Picard, Emilie, Centre de Recherche des Cordeliers (CRC (UMR_S 872)), Université Paris Descartes - Paris 5 (UPD5)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Chimie Nucléaire Analytique et Bio-environnementale (CNAB), Université Sciences et Technologies - Bordeaux 1-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1 (UB)-Centre National de la Recherche Scientifique (CNRS)

Subjects
genetic structures, MESH: Retinal Degeneration, Iron, MESH: Biological Transport, [SDV]Life Sciences [q-bio], Animals, Biological Transport/drug effects, Disease Models, Animal, Electron Probe Microanalysis, Humans, Injections, Intraperitoneal, Iron/metabolism, Mice, Retina/drug effects, Retina/metabolism, Retinal Cone Photoreceptor Cells/drug effects, Retinal Cone Photoreceptor Cells/metabolism, Retinal Degeneration/drug therapy, Retinal Degeneration/pathology, Retinal Rod Photoreceptor Cells/drug effects, Retinal Rod Photoreceptor Cells/metabolism, Spectrometry, X-Ray Emission, Transferrin/administration & dosage, Transferrin/pharmacology, Retina, Retinal Rod Photoreceptor Cells, MESH: Electron Probe Microanalysis, MESH: Animals, MESH: Mice, MESH: Retinal Rod Photoreceptor Cells, MESH: Iron, MESH: Humans, MESH: Retina, Retinal Degeneration, Transferrin, Biological Transport, MESH: Spectrometry, X-Ray Emission, [SDV] Life Sciences [q-bio], MESH: Retinal Cone Photoreceptor Cells, Retinal Cone Photoreceptor Cells, sense organs, MESH: Disease Models, Animal, MESH: Transferrin, MESH: Injections, Intraperitoneal, Research Article
Abstract

International audience; Purpose: Retinal degeneration has been associated with iron accumulation in age-related macular degeneration (AMD), and in several rodent models that had one or several iron regulating protein impairments. We investigated the iron concentration and the protective role of human transferrin (hTf) in rd10 mice, a model of retinal degeneration.Methods: The proton-induced X-ray emission (PIXE) method was used to quantify iron in rd10 mice 2, 3, and 4 weeks after birth. We generated mice with the β-phosphodiesterase mutation and hTf expression by crossbreeding rd10 mice with TghTf mice (rd10/hTf mice). The photoreceptor loss and apoptosis were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling in 3-week-old rd10/hTf mice and compared with 3-week-old rd10 mice. The neuroprotective effect of hTf was analyzed in 5-day-old rd10 mice treated by intraperitoneal administration with hTf for up to 25 days. The retinal hTf concentrations and the thickness of the outer nuclear layer were quantified in all treated mice at 25 days postnatally.Results: PIXE analysis demonstrated an age-dependent iron accumulation in the photoreceptors of rd10 mice. The rd10/hTf mice had the rd10 mutation, expressed high levels of hTf, and showed a significant decrease in photoreceptor death. In addition, rd10 mice intraperitoneally treated with hTf resulted in the retinal presence of hTf and a dose-dependent reduction in photoreceptor degeneration.Conclusions: Our results suggest that iron accumulation in the retinas of rd10 mutant mice is associated with photoreceptor degeneration. For the first time, the enhanced survival of cones and rods in the retina of this model has been demonstrated through overexpression or systemic administration of hTf. This study highlights the therapeutic potential of Tf to inhibit iron-induced photoreceptor cell death observed in degenerative diseases such as retinitis pigmentosa and age-related macular degeneration.

Published
2010

6. STEM and EDXS characterisation of physico-chemical reactions at the periphery of sol-gel derived Zn-substituted hydroxyapatites during interactions with biological fluids

Author

Patrice Laquerriere, Alexia Grandjean-Laquerriere, Dominique Laurent-Maquin, Emmanuelle Chassot, Jean-Marie Nedelec, Anne S. Grimault, Edouard Jallot, Laboratoire des Matériaux Inorganiques (LMI), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Clermont Université-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Interfaces biomatériaux/tissus hôtes, Université de Reims Champagne-Ardenne (URCA)-IFR53-Institut National de la Santé et de la Recherche Médicale (INSERM), and Laurent-Maquin, Dominique

Subjects
Chemical Phenomena, 02 engineering and technology, 01 natural sciences, Chemical reaction, MESH: Zinc, MESH: Body Fluids, Colloid and Surface Chemistry, Scanning transmission electron microscopy, Hydroxyapatites, MESH: Phosphorus, MESH: Hydroxyapatites, Magnesium, Chemistry, Physical, zinc, hydroxyapatite, MESH: Spectrometry, X-Ray Emission, Phosphorus, Surfaces and Interfaces, General Medicine, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Body Fluids, visual_art, MESH: Calcium, visual_art.visual_art_medium, [SDV.IB]Life Sciences [q-bio]/Bioengineering, 0210 nano-technology, Biotechnology, Biocompatibility, MESH: Microscopy, Electron, Scanning, chemistry.chemical_element, Mineralogy, electron probe microanalysis, Zinc, Sol–gel, 010402 general chemistry, Article, Metal, sol-gel, MESH: Chemistry, Physical, Physical and Theoretical Chemistry, Sol-gel, [SDV.IB] Life Sciences [q-bio]/Bioengineering, Spectrometry, X-Ray Emission, 0104 chemical sciences, chemistry, bioactivity, MESH: Spectrometr, Microscopy, Electron, Scanning, Calcium, Nuclear chemistry
Abstract

With its good properties of biocompatibility and bioactivity hydroxyapatite (HA) is highly used as bone substitutes and as coatings on metallic prostheses. In order to improve the bioactive properties of HA, we have elaborated Zn2+ doped hydroxyapatite. Zn2+ ions substitute for Ca2+ cations in the HA structure and four Zn concentrations (Zn/Zn + Ca) were prepared at 0.5, 1, 2 and 5 at.%. To study physico-chemical reactions at the materials periphery, we immersed the bioceramics into biological fluids for intervals from 1 day to 20 days. The surface changes were studied at the nanometer scale by scanning transmission electron microscopy associated with energy dispersive X-ray spectroscopy. After 20 days of immersion, we observed the formation of a calcium–phosphate layer at the periphery of the HA doped with 5% zinc. This layer contains magnesium and its thickness was around 200 nm. Formation of this Ca–P–Mg layer represents the bioactive properties of 5% Zn-substituted hydroxyapatite. This biologically active layer improves the properties of HA and will permit a chemical bond between the ceramic and bone.

Published
2005
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results