The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Asunción Carmona - One of the best experts on this subject based on the ideXlab platform.
-
Correlative organelle fluorescence microscopy and synchrotron X-ray Chemical Element imaging in single cells
Analytical and bioanalytical chemistry, 2014Co-Authors: Stéphane Roudeau, Asunción Carmona, Laura Perrin, Richard OrtegaAbstract:X-ray Chemical Element imaging has the potential to enable fundamental breakthroughs in the understanding of biological systems because Chemical Element interactions with organelles can be studied at the sub-cellular level. What is the distribution of trace metals in cells? Do some Elements accumulate within sub-cellular organelles? What are the Chemical species of the Elements in these organelles? These are some of the fundamental questions that can be addressed by use of X-ray Chemical Element imaging with synchrotron radiation beams. For precise location of the distribution of the Elements, identification of cellular organelles is required; this can be achieved, after appropriate labelling, by use of fluorescence microscopy. As will be discussed, this approach imposes some limitations on sample preparation. For example, standard immunolabelling procedures strongly modify the distribution of the Elements in cells as a result of the Chemical fixation and permeabilization steps. Organelle location can, however, be performed, by use of a variety of specific fluorescent dyes or fluorescent proteins, on living cells before cryogenic fixation, enabling preservation of Element distribution. This article reviews the methods used for fluorescent organelle labelling and X-ray Chemical Element imaging and speciation of single cells. Selected cases from our work and from other research groups are presented to illustrate the potential of the combination of the two techniques.
-
Bio-metals imaging and speciation in cells using proton and synchrotron radiation X-ray microspectroscopy
Journal of the Royal Society Interface, 2009Co-Authors: Richard Ortega, Guillaume Deves, Asunción CarmonaAbstract:The direct detection of biologically relevant metals in single cells and of their speciation is a challenging task that requires sophisticated analytical developments. The aim of this article is to present the recent achievements in the field of cellular Chemical Element imaging, and direct speciation analysis, using proton and synchrotron radiation X-ray micro- and nano-analysis. The recent improvements in focusing optics for MeV-accelerated particles and keV X-rays allow application to Chemical Element analysis in subcellular compartments. The imaging and quantification of trace Elements in single cells can be obtained using particle-induced X-ray emission (PIXE). The combination of PIXE with backscattering spectrometry and scanning transmission ion microscopy provides a high accuracy in Elemental quantification of cellular organelles. On the other hand, synchrotron radiation X-ray fluorescence provides Chemical Element imaging with less than 100 nm spatial resolution. Moreover, synchrotron radiation offers the unique capability of spatially resolved Chemical speciation using micro-X-ray absorption spectroscopy. The potential of these methods in biomedical investigations will be illustrated with examples of application in the fields of cellular toxicology, and pharmacology, bio-metals and metal-based nano-particles.
-
Bio-metals imaging and speciation in cells using proton and synchrotron radiation X-ray micro-spectroscopy
Journal of the Royal Society Interface, 2009Co-Authors: Richard Ortega, Guillaume Deves, Asunción CarmonaAbstract:The direct detection of biologically relevant metals in single cells and of their speciation is a challenging task that requires sophisticated analytical developments. The aim of this article is to present the recent achievements in the field of cellular Chemical Element imaging, and direct speciation analysis, using proton and synchrotron radiation X-ray micro- and nano-analysis. The recent improvements in focusing optics for MeV-accelerated particles and keV X-rays allow application to Chemical Element analysis in subcellular compartments. The imaging and quantification of trace Elements in single cells can be obtained using particle-induced X-ray emission (PIXE). The combination of PIXE with backscattering spectrometry and scanning transmission ion microscopy provides a high accuracy in Elemental quantification of cellular organelles. On the other hand, synchrotron radiation X-ray fluorescence provides Chemical Element imaging with less than 100 nm spatial resolution. Moreover, synchrotron radiation offers the unique capability of spatially resolved Chemical speciation using micro-X-ray absorption spectroscopy. The potential of these methods in biomedical investigations will be illustrated with examples of application in the fields of cellular toxicology, and pharmacology, bio-metals and metal-based nano-particles.
Richard Ortega - One of the best experts on this subject based on the ideXlab platform.
-
Correlative organelle fluorescence microscopy and synchrotron X-ray Chemical Element imaging in single cells
Analytical and bioanalytical chemistry, 2014Co-Authors: Stéphane Roudeau, Asunción Carmona, Laura Perrin, Richard OrtegaAbstract:X-ray Chemical Element imaging has the potential to enable fundamental breakthroughs in the understanding of biological systems because Chemical Element interactions with organelles can be studied at the sub-cellular level. What is the distribution of trace metals in cells? Do some Elements accumulate within sub-cellular organelles? What are the Chemical species of the Elements in these organelles? These are some of the fundamental questions that can be addressed by use of X-ray Chemical Element imaging with synchrotron radiation beams. For precise location of the distribution of the Elements, identification of cellular organelles is required; this can be achieved, after appropriate labelling, by use of fluorescence microscopy. As will be discussed, this approach imposes some limitations on sample preparation. For example, standard immunolabelling procedures strongly modify the distribution of the Elements in cells as a result of the Chemical fixation and permeabilization steps. Organelle location can, however, be performed, by use of a variety of specific fluorescent dyes or fluorescent proteins, on living cells before cryogenic fixation, enabling preservation of Element distribution. This article reviews the methods used for fluorescent organelle labelling and X-ray Chemical Element imaging and speciation of single cells. Selected cases from our work and from other research groups are presented to illustrate the potential of the combination of the two techniques.
-
Bio-metals imaging and speciation in cells using proton and synchrotron radiation X-ray microspectroscopy
Journal of the Royal Society Interface, 2009Co-Authors: Richard Ortega, Guillaume Deves, Asunción CarmonaAbstract:The direct detection of biologically relevant metals in single cells and of their speciation is a challenging task that requires sophisticated analytical developments. The aim of this article is to present the recent achievements in the field of cellular Chemical Element imaging, and direct speciation analysis, using proton and synchrotron radiation X-ray micro- and nano-analysis. The recent improvements in focusing optics for MeV-accelerated particles and keV X-rays allow application to Chemical Element analysis in subcellular compartments. The imaging and quantification of trace Elements in single cells can be obtained using particle-induced X-ray emission (PIXE). The combination of PIXE with backscattering spectrometry and scanning transmission ion microscopy provides a high accuracy in Elemental quantification of cellular organelles. On the other hand, synchrotron radiation X-ray fluorescence provides Chemical Element imaging with less than 100 nm spatial resolution. Moreover, synchrotron radiation offers the unique capability of spatially resolved Chemical speciation using micro-X-ray absorption spectroscopy. The potential of these methods in biomedical investigations will be illustrated with examples of application in the fields of cellular toxicology, and pharmacology, bio-metals and metal-based nano-particles.
-
Bio-metals imaging and speciation in cells using proton and synchrotron radiation X-ray micro-spectroscopy
Journal of the Royal Society Interface, 2009Co-Authors: Richard Ortega, Guillaume Deves, Asunción CarmonaAbstract:The direct detection of biologically relevant metals in single cells and of their speciation is a challenging task that requires sophisticated analytical developments. The aim of this article is to present the recent achievements in the field of cellular Chemical Element imaging, and direct speciation analysis, using proton and synchrotron radiation X-ray micro- and nano-analysis. The recent improvements in focusing optics for MeV-accelerated particles and keV X-rays allow application to Chemical Element analysis in subcellular compartments. The imaging and quantification of trace Elements in single cells can be obtained using particle-induced X-ray emission (PIXE). The combination of PIXE with backscattering spectrometry and scanning transmission ion microscopy provides a high accuracy in Elemental quantification of cellular organelles. On the other hand, synchrotron radiation X-ray fluorescence provides Chemical Element imaging with less than 100 nm spatial resolution. Moreover, synchrotron radiation offers the unique capability of spatially resolved Chemical speciation using micro-X-ray absorption spectroscopy. The potential of these methods in biomedical investigations will be illustrated with examples of application in the fields of cellular toxicology, and pharmacology, bio-metals and metal-based nano-particles.
Guillaume Deves - One of the best experts on this subject based on the ideXlab platform.
-
Bio-metals imaging and speciation in cells using proton and synchrotron radiation X-ray microspectroscopy
Journal of the Royal Society Interface, 2009Co-Authors: Richard Ortega, Guillaume Deves, Asunción CarmonaAbstract:The direct detection of biologically relevant metals in single cells and of their speciation is a challenging task that requires sophisticated analytical developments. The aim of this article is to present the recent achievements in the field of cellular Chemical Element imaging, and direct speciation analysis, using proton and synchrotron radiation X-ray micro- and nano-analysis. The recent improvements in focusing optics for MeV-accelerated particles and keV X-rays allow application to Chemical Element analysis in subcellular compartments. The imaging and quantification of trace Elements in single cells can be obtained using particle-induced X-ray emission (PIXE). The combination of PIXE with backscattering spectrometry and scanning transmission ion microscopy provides a high accuracy in Elemental quantification of cellular organelles. On the other hand, synchrotron radiation X-ray fluorescence provides Chemical Element imaging with less than 100 nm spatial resolution. Moreover, synchrotron radiation offers the unique capability of spatially resolved Chemical speciation using micro-X-ray absorption spectroscopy. The potential of these methods in biomedical investigations will be illustrated with examples of application in the fields of cellular toxicology, and pharmacology, bio-metals and metal-based nano-particles.
-
Bio-metals imaging and speciation in cells using proton and synchrotron radiation X-ray micro-spectroscopy
Journal of the Royal Society Interface, 2009Co-Authors: Richard Ortega, Guillaume Deves, Asunción CarmonaAbstract:The direct detection of biologically relevant metals in single cells and of their speciation is a challenging task that requires sophisticated analytical developments. The aim of this article is to present the recent achievements in the field of cellular Chemical Element imaging, and direct speciation analysis, using proton and synchrotron radiation X-ray micro- and nano-analysis. The recent improvements in focusing optics for MeV-accelerated particles and keV X-rays allow application to Chemical Element analysis in subcellular compartments. The imaging and quantification of trace Elements in single cells can be obtained using particle-induced X-ray emission (PIXE). The combination of PIXE with backscattering spectrometry and scanning transmission ion microscopy provides a high accuracy in Elemental quantification of cellular organelles. On the other hand, synchrotron radiation X-ray fluorescence provides Chemical Element imaging with less than 100 nm spatial resolution. Moreover, synchrotron radiation offers the unique capability of spatially resolved Chemical speciation using micro-X-ray absorption spectroscopy. The potential of these methods in biomedical investigations will be illustrated with examples of application in the fields of cellular toxicology, and pharmacology, bio-metals and metal-based nano-particles.
-
Chemical Element Imaging and Speciation in Cells using Nuclear Microprobe and Synchrotron Nanoprobe
2006Co-Authors: Guillaume DevesAbstract:Development and application of nuclear microprobe and synchrotron nanoprobe for Chemical Elements imaging in biological samples
Alain Meunier - One of the best experts on this subject based on the ideXlab platform.
-
A new method for quantitative petrography based on image processing of Chemical Element maps: Part I. Mineral mapping applied to compacted bentonites
American Mineralogist, 2010Co-Authors: Dimitri Prêt, Stéphane Sammartino, Daniel Beaufort, Alain Meunier, Michel Fialin, Laurent J. MichotAbstract:Most natural rocks or engineered materials display a multi-scale heterogeneity ranging from the nanometer to the centimeter. Their spatial textural heterogeneity can be approached from Chemical Element maps acquired using various techniques (SEM, EPMA, SXAM, synchrotron μ-XRF, TEM), depending on the chosen magnification. Chemical map processing that yields quantitative petrographic information is improved here according to newly developed mineral thresholding methods that accommodate mixtures and solid solutions. The complex case of an MX80 compacted bentonite is used as a test case. The 14 major Chemical Elements of this sample were mapped using an electron probe microanalyzer, and Chemical map processing yielded a quantitative map of the 18 mineral species of bentonite with a spatial resolution of a few micrometers. The textural heterogeneity of the solid part of the sample is thus visualized and quantified on an area ranging between 0.1–1 cm2. The method also provides a complete modal analysis of the sample. The methodology is expected to have broad applications in Earth and materials sciences.
-
A new method for quantitative petrography based on image processing of Chemical Element maps: Part II. Semi-quantitative porosity maps superimposed on mineral maps
American Mineralogist, 2010Co-Authors: Dimitri Prêt, Stéphane Sammartino, Daniel Beaufort, Michel Fialin, Paul Sardini, Philippe Cosenza, Alain MeunierAbstract:Visualizing and quantifying the spatial heterogeneity of rock textures (i.e., mineral and porosity distributions) is of great interest in petrology or for understanding petrophysical properties. Spatial heterogeneities are not accurately revealed by usual techniques based on microscopy or bulk physical measurements. Detailed mineral mapping is already available from processing of Chemical Element maps acquired using an electron probe microanalyzer (Part I). The present paper is devoted to developing a new, coupled method for obtaining porosity maps from the same initial data. According to the difference between measured and theoretical sums of oxide weight percentages, a mean porosity is semi-quantitatively estimated for each pixel of the map (i.e., not fully absolute or accurate). All pores, including nanometer-size ones, are taken into account, whereas a sample area of several square millimeters is analyzed (spatial resolution of a few micrometers). The textural heterogeneities are thus visualized from the complementary maps of solids and voids. By superimposing these two maps, both the mean porosity and a porosity histogram associated with each rock-forming mineral are obtained. Such porosity measurements integrate the pore amounts within mono-crystals larger than the X-ray emission volume or between nanometer-size crystals of a matrix. When porosity changes are associated with a given mineral (various crystal arrangements, dissolution, etc.), pluri-modal distributions appear on porosity histograms. Thresholding each histogram mode then allows these processes to be localized. We used the MX80 bentonite to test this methodology, which represents a useful tool to study the local deformations and alteration of each rock-forming mineral, as well as to model transport properties.
Dimitri Prêt - One of the best experts on this subject based on the ideXlab platform.
-
A new method for quantitative petrography based on image processing of Chemical Element maps: Part I. Mineral mapping applied to compacted bentonites
American Mineralogist, 2010Co-Authors: Dimitri Prêt, Stéphane Sammartino, Daniel Beaufort, Alain Meunier, Michel Fialin, Laurent J. MichotAbstract:Most natural rocks or engineered materials display a multi-scale heterogeneity ranging from the nanometer to the centimeter. Their spatial textural heterogeneity can be approached from Chemical Element maps acquired using various techniques (SEM, EPMA, SXAM, synchrotron μ-XRF, TEM), depending on the chosen magnification. Chemical map processing that yields quantitative petrographic information is improved here according to newly developed mineral thresholding methods that accommodate mixtures and solid solutions. The complex case of an MX80 compacted bentonite is used as a test case. The 14 major Chemical Elements of this sample were mapped using an electron probe microanalyzer, and Chemical map processing yielded a quantitative map of the 18 mineral species of bentonite with a spatial resolution of a few micrometers. The textural heterogeneity of the solid part of the sample is thus visualized and quantified on an area ranging between 0.1–1 cm2. The method also provides a complete modal analysis of the sample. The methodology is expected to have broad applications in Earth and materials sciences.
-
A new method for quantitative petrography based on image processing of Chemical Element maps: Part II. Semi-quantitative porosity maps superimposed on mineral maps
American Mineralogist, 2010Co-Authors: Dimitri Prêt, Stéphane Sammartino, Daniel Beaufort, Michel Fialin, Paul Sardini, Philippe Cosenza, Alain MeunierAbstract:Visualizing and quantifying the spatial heterogeneity of rock textures (i.e., mineral and porosity distributions) is of great interest in petrology or for understanding petrophysical properties. Spatial heterogeneities are not accurately revealed by usual techniques based on microscopy or bulk physical measurements. Detailed mineral mapping is already available from processing of Chemical Element maps acquired using an electron probe microanalyzer (Part I). The present paper is devoted to developing a new, coupled method for obtaining porosity maps from the same initial data. According to the difference between measured and theoretical sums of oxide weight percentages, a mean porosity is semi-quantitatively estimated for each pixel of the map (i.e., not fully absolute or accurate). All pores, including nanometer-size ones, are taken into account, whereas a sample area of several square millimeters is analyzed (spatial resolution of a few micrometers). The textural heterogeneities are thus visualized from the complementary maps of solids and voids. By superimposing these two maps, both the mean porosity and a porosity histogram associated with each rock-forming mineral are obtained. Such porosity measurements integrate the pore amounts within mono-crystals larger than the X-ray emission volume or between nanometer-size crystals of a matrix. When porosity changes are associated with a given mineral (various crystal arrangements, dissolution, etc.), pluri-modal distributions appear on porosity histograms. Thresholding each histogram mode then allows these processes to be localized. We used the MX80 bentonite to test this methodology, which represents a useful tool to study the local deformations and alteration of each rock-forming mineral, as well as to model transport properties.