Correlative transmission electron microscopy and high-resolution hard X-ray fluorescence microscopy of cell sections to measure trace elements concentrations at the organelle level

AbstractMetals are essential to all forms of life and their concentration and distribution in the organisms are tightly regulated. Indeed, in their free form, metal ions are toxic. Therefore, an excess of physiologic metal ions or the uptake of non-physiologic metal ions can be highly detrimental for the organisms. It is thus fundamental to understand metals distribution and dynamics in physiologic or disrupted conditions, for instance in metal-related pathologies or upon environmental exposure to metals. Elemental imaging techniques can serve this purpose, by allowing the visualization and the quantification of metal species in a tissue or down to the interior of a cell. Among these techniques, synchrotron radiation-based X-ray fluorescence (SR-XRF) microscopy is the most sensitive to date, and great progresses were made to reach spatial resolutions as low as 20×20 nm2. Until recently, 2D XRF mapping was used on whole cells, thus summing up the signal from the whole thickness of the cell. In the last two years, we have developed a methodology to work on thin cell sections, in order to analyze the metal content at the level of the organelle. Herein, we propose a correlative method to couple SR-XRF to electron microscopy, with the aim to quantify the elemental content in an organelle of interest. As a proof-of-concept, the technique was applied to the analysis of mitochondria from hepatocytes exposed to silver nanoparticles. It was thus possible to identify mitochondria with higher concentration of Ag(I) ions compared to the surrounding cytosol. The versatility of the method makes it suitable to answer a large panel of biological questions, for instance related to metal homeostasis in biological organisms.

Download Full-text

Electrolytic synthesis of ZrSi/ZrC nanocomposites from ZrSiO4 and carbon black powder in molten salt

International Journal of Materials Research (formerly Zeitschrift fuer Metallkunde) ◽

10.1515/ijmr-2020-1110707 ◽

2020 ◽

Vol 111 (7) ◽

pp. 581-586

Author(s):

Li Ming ◽

Wu Xiufeng

Keyword(s):

Electron Microscopy ◽

High Temperature ◽

Carbon Black ◽

Molten Salt ◽

Cell Voltage ◽

Black Powder ◽

X Ray ◽

Carbon Black Powder ◽

Transmission Electron ◽

A Cell

Abstract ZrSi/ZrC nanocomposites have stable high-temperature properties, where conventional materials cannot meet increasingly demanding high-temperature environments. In this paper, the microstructure and electrochemical reduction mechanism of ZrSi/ZrC nanocomposites have been studied. A mixture of ZrSiO4 and carbon black powder was processed using ball grinding, sheet pressing, and sintering, and cylindrically-sintered sheet was prepared as the cathode for the electrolytic work. A high purity graphite rod was utilized as the anode.The microstructure of the electrolytic product was characterized and analyzed using X-ray diffraction, scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, and transmission electron microscopy. The experimental results showed that the diameter of the as-synthesized ZrSi/ ZrC fibers typically range between 100-400 nm when produced by the electrolysis of sintered pellets in equimolar CaCl2-NaCl molten salt at 850°C with a cell voltage of 2.8 V for 20 h under an argon atmosphere. The nanofibers were formed in core-shell microstructures that overlap and grow.

Download Full-text

Biosynthesized Highly Stable Au/C Nanodots: Ideal Probes for the Selective and Sensitive Detection of Hg2+ Ions

Nanomaterials ◽

10.3390/nano9020245 ◽

2019 ◽

Vol 9 (2) ◽

pp. 245 ◽

Cited By ~ 4

Author(s):

Sada Venkateswarlu ◽

Saravanan Govindaraju ◽

Roopkumar Sangubotla ◽

Jongsung Kim ◽

Min-Ho Lee ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Metal Ions ◽

Fluorescent Probe ◽

Photoelectron Spectroscopy ◽

Industrial Development ◽

Carbon Nanodots ◽

Detection Mechanism ◽

X Ray ◽

Transmission Electron

The enormous ongoing industrial development has caused serious water pollution which has become a major crisis, particularly in developing countries. Among the various water pollutants, non-biodegradable heavy metal ions are the most prevalent. Thus, trace-level detection of these metal ions using a simple technique is essential. To address this issue, we have developed a fluorescent probe of Au/C nanodots (GCNDs-gold carbon nanodots) using an eco-friendly method based on an extract from waste onion leaves (Allium cepa-red onions). The leaves are rich in many flavonoids, playing a vital role in the formation of GCNDs. Transmission electron microscopy (TEM) and Scanning transmission electron microscopy-Energy-dispersive X-ray spectroscopy (STEM-EDS) elemental mapping clearly indicated that the newly synthesized materials are approximately 2 nm in size. The resulting GCNDs exhibited a strong orange fluorescence with excitation at 380 nm and emission at 610 nm. The GCNDs were applied as a fluorescent probe for the detection of Hg2+ ions. They can detect ultra-trace concentrations of Hg2+ with a detection limit of 1.3 nM. The X-ray photoelectron spectroscopy results facilitated the identification of a clear detection mechanism. We also used the new probe on a real river water sample. The newly developed sensor is highly stable with a strong fluorescent property and can be used for various applications such as in catalysis and biomedicine.

Download Full-text

New coordination polymers of glyoxal bis(2-hydroxyanil)

High Performance Polymers ◽

10.1088/0954-0083/7/4/005 ◽

1995 ◽

Vol 7 (4) ◽

pp. 433-441 ◽

Cited By ~ 3

Author(s):

Salah A EI-Shatoury

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Metal Ions ◽

Coordination Polymers ◽

Elemental Analysis ◽

Electronic Spectra ◽

Metal Content ◽

X Ray ◽

Dsc Analyses ◽

Scanning Electron

Coordination polymers of [2,2'-(ethandiylidenedinitrilo) diphenol) have been prepared with the metal ions Cu(II), Ni(1I) and Cr(III). They were characterized by elemental analysis, IR and electronic spectra. The metal content in all polymers was found to be consistent with a 1:1 (metal:ligand) stoichiometry. The thermal behaviour of these coordination polymers has been studied by thermogravimetric and DSC analyses in air up to 500 C. The crystallinity of the formed polymers was determined by x-ray analysis. The morphological structures of these polymers were determined by scanning electron microscopy.

Download Full-text

Synergistically homogeneous-heterogeneous Fenton catalysis of trace copper ion and g-C3N4 for degradation of organic pollutants

Water Science & Technology ◽

10.2166/wst.2021.296 ◽

2021 ◽

Author(s):

Z. Y. Yao ◽

G. X. Zhu ◽

T. L. Lu ◽

Y. Z. Zhan

Keyword(s):

Electron Microscopy ◽

Catalytic Activity ◽

Metal Ions ◽

Photoelectron Spectroscopy ◽

Organic Pollutant ◽

Copper Ion ◽

Heterogeneous Fenton ◽

Paramagnetic Resonance ◽

X Ray ◽

Synergistic Catalysis

Abstract Using the bulk g-C3N4 as a precursor, four g-C3N4 nanosheets were further prepared by ultrasonic, thermal, acid, and alkali exfoliation. The structures of these materials were characterized by various techniques such as X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-Ray spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The synergistical Fenton catalysis of these materials with Cu2+ was evaluated by using rhodamine B as a simulated organic pollutant. The results showed that there existed a significant synergistical Fenton catalysis between Cu2+ and g-C3N4. This synergistic effect can be observed even when the concentration of Cu2+ was as low as 0.064 mg L−1. The properties of g-C3N4 strongly influenced the catalytic activity of the Cu2+/g-C3N4 system. The coexistent of Cu2+ and the alkali exfoliated g-C3N4 showed the most excellent catalytic activity. Hydroxyl radicals as oxidizing species were confirmed in the Cu2+/g-C3N4 system by electron paramagnetic resonance spectrum. The synergistic catalysis may be attributed to the easier reduction of Cu2+ adsorbed on the g-C3N4. This study provided an excellent Fenton catalytic system, and partly solved the rapid deactivation of heterogeneous Fenton catalysts caused by the leaching of metal ions. HIGHTLIGHTS There exists a significant synergistical Fenton catalysis between trace Cu2+ and g-C3N4. The Cu2+ concentration is lower than the maximum acceptable limit in drinking water. This study partly solved the rapid deactivation caused by the leaching of metal ions. This study reminds researchers to pay attention to the possible synergistic catalysis between leached ions and supports.

Download Full-text

Electron microscopy of superconducting and related oxides

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010634x ◽

1988 ◽

Vol 46 ◽

pp. 856-857

Author(s):

K. J. Morrissey ◽

M. A. Subramanian ◽

C. C. Torardi ◽

E. M. McCarron ◽

J. C. Calabrese ◽

...

Keyword(s):

Electron Microscopy ◽

Imaging Techniques ◽

Structural Defects ◽

Materials Synthesis ◽

X Ray ◽

Superconducting Phases ◽

Novel Synthesis ◽

Structure Determinations ◽

Powder Samples ◽

Synthesis Routes

It is important to combine characterization techniques such as electron microscopy with novel materials synthesis in the study of high Tc superconducting phases. Results from electron microscopy studies have been correlated with structure determinations made using x-ray and neutron diffraction (1.2,3.4). Superconducting phases studied to date include YBa2Cu3O7-x, La1.25Ba1.75Cu3O7, Bi2Sr2CuO6, Bi2Sr2CaCu2O8, Tl2Ba2CuO6 Tl2Ba2CaCu2O8, and Tl2Ba2Ca2Cu3O8. A comparison between structures and defect populations suggests that structural defects, which modify the Cu-O arrangement (sheets or chains) intergrowths and grain boundaries, will affect superconductivity. Techniques used in this investigation include HREM, CBED, AEM, SAD and conventional imaging techniques.Samples characterized in this study were prepared in our laboratory, using both conventional and novel synthesis routes. Powder samples in the Tl-Ba-Cu-O system were prepared by heating mixtures of high purity BaO2, Tl2O2 and CuO to 850-900°C in sealed gold tubes for 1-6 hours (3,4). Similar procedures were followed in the Bi2Sr2CaCu2O8 system using Bi2O3, CaCO3, SrO2/Sr(NO3)2 and CuO. heating the mixtures in air at 700-900°C for 12-36 hours (2.4).

Download Full-text

Multimodal x-ray and electron microscopy of the Allende meteorite

Science Advances ◽

10.1126/sciadv.aax3009 ◽

2019 ◽

Vol 5 (9) ◽

pp. eaax3009 ◽

Cited By ~ 4

Author(s):

Yuan Hung Lo ◽

Chen-Ting Liao ◽

Jihan Zhou ◽

Arjun Rana ◽

Charles S. Bevis ◽

...

Keyword(s):

Electron Microscopy ◽

Spatial Resolution ◽

Electron Tomography ◽

Imaging Techniques ◽

Three Dimensional ◽

Functional Materials ◽

Atomic Scale ◽

Chemical Mapping ◽

X Ray ◽

Orientation Contrast

Multimodal microscopy that combines complementary nanoscale imaging techniques is critical for extracting comprehensive chemical, structural, and functional information, particularly for heterogeneous samples. X-ray microscopy can achieve high-resolution imaging of bulk materials with chemical, magnetic, electronic, and bond orientation contrast, while electron microscopy provides atomic-scale spatial resolution with quantitative elemental composition. Here, we combine x-ray ptychography and scanning transmission x-ray spectromicroscopy with three-dimensional energy-dispersive spectroscopy and electron tomography to perform structural and chemical mapping of an Allende meteorite particle with 15-nm spatial resolution. We use textural and quantitative elemental information to infer the mineral composition and discuss potential processes that occurred before or after accretion. We anticipate that correlative x-ray and electron microscopy overcome the limitations of individual imaging modalities and open up a route to future multiscale nondestructive microscopies of complex functional materials and biological systems.

Download Full-text

Detection of isolated protein-bound metal ions by single-particle cryo-STEM

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1708609114 ◽

2017 ◽

Vol 114 (42) ◽

pp. 11139-11144 ◽

Cited By ~ 13

Author(s):

Nadav Elad ◽

Giuliano Bellapadrona ◽

Lothar Houben ◽

Irit Sagi ◽

Michael Elbaum

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Metal Ions ◽

Single Particle ◽

Dark Field ◽

X Ray ◽

X Ray Crystallography ◽

Metal Atoms ◽

Transmission Electron ◽

Structural Methods

Metal ions play essential roles in many aspects of biological chemistry. Detecting their presence and location in proteins and cells is important for understanding biological function. Conventional structural methods such as X-ray crystallography and cryo-transmission electron microscopy can identify metal atoms on protein only if the protein structure is solved to atomic resolution. We demonstrate here the detection of isolated atoms of Zn and Fe on ferritin, using cryogenic annular dark-field scanning transmission electron microscopy (cryo-STEM) coupled with single-particle 3D reconstructions. Zn atoms are found in a pattern that matches precisely their location at the ferroxidase sites determined earlier by X-ray crystallography. By contrast, the Fe distribution is smeared along an arc corresponding to the proposed path from the ferroxidase sites to the mineral nucleation sites along the twofold axes. In this case the single-particle reconstruction is interpreted as a probability distribution function based on the average of individual locations. These results establish conditions for detection of isolated metal atoms in the broader context of electron cryo-microscopy and tomography.

Download Full-text

Toward A Reproducible, Scalable Framework for Processing Large Neuroimaging Datasets

10.1101/615161 ◽

2019 ◽

Cited By ~ 3

Author(s):

Erik C. Johnson ◽

Miller Wilt ◽

Luis M. Rodriguez ◽

Raphael Norman-Tenazas ◽

Corban Rivera ◽

...

Keyword(s):

Electron Microscopy ◽

Open Source ◽

Data Storage ◽

Large Scale ◽

Imaging Techniques ◽

Scientific Discovery ◽

Imaging Data ◽

Considerable Difficulty ◽

X Ray ◽

The Brain

ABSTRACTEmerging neuroimaging datasets (collected through modalities such as Electron Microscopy, Calcium Imaging, or X-ray Microtomography) describe the location and properties of neurons and their connections at unprecedented scale, promising new ways of understanding the brain. These modern imaging techniques used to interrogate the brain can quickly accumulate gigabytes to petabytes of structural brain imaging data. Unfortunately, many neuroscience laboratories lack the computational expertise or resources to work with datasets of this size: computer vision tools are often not portable or scalable, and there is considerable difficulty in reproducing results or extending methods. We developed an ecosystem of neuroimaging data analysis pipelines that utilize open source algorithms to create standardized modules and end-to-end optimized approaches. As exemplars we apply our tools to estimate synapse-level connectomes from electron microscopy data and cell distributions from X-ray microtomography data. To facilitate scientific discovery, we propose a generalized processing framework, that connects and extends existing open-source projects to provide large-scale data storage, reproducible algorithms, and workflow execution engines. Our accessible methods and pipelines demonstrate that approaches across multiple neuroimaging experiments can be standardized and applied to diverse datasets. The techniques developed are demonstrated on neuroimaging datasets, but may be applied to similar problems in other domains.

Download Full-text

LignoPhot: Photoactive Hybrid lignin/Bi4O5Br2/BiOBr Composite for Complex Pollutants Removal

10.26434/chemrxiv.13554677 ◽

2021 ◽

Author(s):

Tetyana Budnyak ◽

Joy Onwumere ◽

Ievgen V. Pylypchuk ◽

Aleksander Jaworski ◽

Jianhong Chen ◽

...

Keyword(s):

Electron Microscopy ◽

Metal Ions ◽

Photoelectron Spectroscopy ◽

Organic Dyes ◽

Dye Degradation ◽

Low Cost ◽

Resonance Spectroscopy ◽

Hydrolysis Lignin ◽

X Ray ◽

Main Component

Valorization of lignin is still an open question and lignin has therefore remained an underutilized biomaterial. This situation is even more pronounced for hydrolysis lignin, which is characterized by a highly condensed and excessively cross-linked structure. We report on photoactive lignin/Bi4O5Br2/BiOBr bio-inorganic composites consisting of a lignin substrate that is coated by Bi4O5Br2/BiOBr nanosheet photocatalysts. The structure of the hybrid material was investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy including energy dispersive X-ray (EDX) spectroscopy, and solid state 1H−13C nuclear magnetic resonance spectroscopy (1H−13C NMR). The material contains 18.9% of Bi4O5Br2/BiOBr and was found to be effective for the photocatalytic degradation of cationic methylene blue (MB) and zwitterionic rhodamine B (RhB) dyes under irradiation with 405 nm light. Lignin/Bi4O5Br2/BiOBr was able to decrease the dye concentration from 80 mg·L–1 to 12.3 mg·L–1 for RhB (85%) and from 80 mg·L–1 to 4.4 mg·L–1 for MB (95%). Complementary to the dye degradation, the lignin as a main component of the composite, was found to be efficient and rapid biosorbent for metal ions in aqueous solutions. The highest adsorption capacity was found after 2 hours of phases contact and reached 0.45 mmol·g–1 for Ni(II) ions (neutral media). The low cost, simplicity of the synthesis, good stability and ability to simultaneously photooxidize organic dyes and to adsorb metal ions, make the developed photoactive lignin/Bi4O5Br2/BiOBr composite a prospective material for textile wastewaters remediation

Download Full-text

Elemental Analysis in Disease Progression and Diagnosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053978 ◽

1982 ◽

Vol 40 ◽

pp. 266-269

Author(s):

S. S. Barham ◽

J. E. Tarara

Keyword(s):

Electron Microscopy ◽

Disease Progression ◽

Soft Tissues ◽

Cultured Cells ◽

Analytical Electron Microscopy ◽

Biological Tissues ◽

Disease Diagnosis ◽

Elemental Content ◽

Specimen Preparation ◽

X Ray

Analytical electron microscopy is an important research tool that has found increasing use in disease diagnosis as well as investigation of disease progression. Energy dispersive x-ray spectrometers coupled with transmission, scanning, or scanning transmission electron microscopes have become accepted as useful aids to the pathologist in elemental identification and localization in human tissues. Many elements and compounds can be identified and localized in tissues using modifications of routine specimen preparation procedures for electron microscopy. This methodology limits the study of soluble electrolyte localization in tissues. Methods for localizing cellular cations or anions must still be performed using snap-freezing and vacuum drying procedures combined with ultracryomicrotomy or ion-capture cytochemistry such as pyroantimonate precipitation of cations. However, most metals and insoluble compounds can be localized in soft biological tissues by x-ray microanalysis while avoiding cryopreparative procedures that can be expensive, time consuming, and requisite of a high level of technical skill. Examples of this application of x-ray analysis of elemental content in soft tissues will be illustrated and discussed: metal loading of liver tissue associated with disease progression, sideroblastic anemias, pulmonary tissue inclusions, uptake of oil shale particulates by cultured cells, gold nephropathy, and chrysiasis.

Download Full-text