X-ray microscopy – Lightsources.org

Magnetotactic microorganisms studied through materials science and advanced imaging

2023/06/082023/06/13

Researchers from the Bioscience and Biotechnology Institute of Aix-Marseille (BIAM) have recently published a new work in the journal Proceedings of the National Academy of Science. The study reveals a singular association between magnetotactic bacteria and their host, a unicellular eukaryote (protist).

Magnetoreception is a function unique in the world of the living. Microorganisms are capable of perceiving and reacting to fluctuations in their environment: temperature, light, pressure, gravity, etc. The Earth’s magnetic field is also perceived by certain microorganisms: magnetotactic bacteria, whose mobility is guided by geomagnetic field lines. Magnetoreception guides their movement in aquatic sediments while locating more easily specific depths of the surface. In the microbial world, magnetoreception is based on the synthesis of intracellular chains of magnetic nanocrystals. It is currently the only form of geolocation to have been characterized by scientists.

All the microorganisms sensitive to the magnetic field described so far associate magnetoreception with sensory systems dedicated to certain physicochemical signals, thanks to which they can navigate towards or away from specific substances. This navigation behavior is called magnetotaxis and was, until recently, only observed in magnetotactic bacteria present in areas with strong chemical gradients such as aquatic sediments. By guiding their movement along vertical lines rather than in three-dimensions, their magnetism allows them to more easily find the zone where conditions are optimal for their growth. However, findings by researchers at the BIAM, revealed in 2019 that protists had also acquired this ability through a singular strategy. Some flagellated protists acquired magnetotaxis by associating with magnetotactic bacteria attached to their surface, becoming indispensable symbionts during evolution. This discovery, “revealed that magnetotaxis was performed collectively, with the eukaryotic host enabling swimming and perception of the chemical environment on one hand and the bacterial symbionts producing the nano-sized magnetic needles on the other. However, we did not yet uncover how these partners interacted from a physical point of view and how the magnetic properties are formed,” says Christopher Lefèvre, co-coordinator of the study.

When microbiology meets materials science and advanced imaging techniques

The study of living systems interactions at the microscopic scale would still be inaccessible without interdisciplinarity of scientists equipped with advanced scientific techniques. “Studying such an environmental biological system is difficult due to their size, low abundance and lack of models in culture, pushing technological limits,”comments Daniel Chevrier, CNRS researcher at BIAM, first author and also co-coordinator of the study. Researchers had to deploy “an arsenal of approaches and technologies”, including synchrotron-based X-ray microscopy at MISTRAL beamline of the ALBA Synchrotron.

Read more on the ALBA website

Image: Magnetotactic holobiont – the host is a unicellular eukaryote with magnetotactic bacteria on its surface

European Young Chemists’ Award for Sebastian Weber

2022/09/262022/09/29

In recognition of Sebastian’s PhD thesis on hard X-ray microscopy, tomography, and application of synchrotron radiation in catalysis research

Sebastian Weber, a recent PhD graduate at the Institute for Chemical Technology and Polymer Chemistry (ITCP) / Institute for Catalysis Research and Technology (IKFT) at Karlsruhe Institute of Technology (KIT), was awarded the Gold Medal in the PhD category of the European Young Chemists‘ Award. The award is presented every two years during the EuChemS Chemistry Congress on behalf of the Società Chimica Italiana (SCI) and the European Chemical Society (EuChemS). The prize highlights excellent research from young / early stage researchers across all fields of chemistry and chemical sciences. During his PhD phase, Sebastian Weber studied materials used in heterogeneous catalysis with a broad range of spatially-resolved X-ray characterisation methods, in order to gain a deeper understanding of the structure and function of catalysts. The project made extensive use of synchrotron radiation, specifically X-ray microscopy and tomography as emerging methods in catalysis research. This success on the European level highlights the leading role which synchrotron science has to play in the study of matter.

Catalysis plays a crucial role in sustainable chemical production, chemical energy conversion and storage, among many others, and is a key technology area in synchrotron radiation research. During his PhD work at Karlsruhe Institute of Technology, Sebastian Weber studied catalysts for CO₂ methanation using spatially-resolved characterisation tools including X-ray microscopy and tomography. These diverse X-ray imaging methods were exploited to study the 3D structure of catalytic materials over a range of length scales, addressing various levels of hierarchical structural features which are critical to understanding catalyst performance. This topic is a special focus of the Young Investigator Group of Dr. Thomas Sheppard at KIT, who supervised and secured funding for the project, within the wider group of Prof. Jan-Dierk Grunwaldt.

Only a handful of research groups worldwide are currently active in the field of X-ray microscopy applied to catalysis research, highlighting the emerging role of this vibrant research field. During his PhD work, Sebastian Weber in particular worked to develop applications of hard X-ray ptychography and ptychographic X-ray tomography (PXCT) to study catalyst pore structures, structural evolution under reaction conditions, and the effects of catalyst deactivation. These methods routinely reach spatial resolution below 50 nanometres (0.001 x diameter of a human hair), and have been applied so far on samples up to 50 micron in diameter (ca. the diameter of a human hair). The further development of ptychography holds excellent potential for catalysis and materials research, particularly in the age of fourth generation light sources with improved coherence and decreased source emittance. The project resulted in several high quality publications in leading chemistry and materials journals, reflecting the knowledge gained regarding 3D structure of catalysts, and the potential for development of improved catalysts in future.

Sebastian Weber recently completed his doctorate with the title “Revealing Porosity and Structure of Ni-based Catalysts for Dynamic CO₂ Methanation with Hard X-rays”, earning a distinction from KIT. Now his work was further recognised by securing the Gold Medal of the European Young Chemists’ Award at PhD level. The award is presented every two years during the EuChemS Chemistry Congress on behalf of the Società Chimica Italiana (SCI) and the European Chemical Society (EuChemS). The prize highlights excellent research from young / early stage researchers across all fields of chemistry and chemical sciences, and is therefore a highly competitive prize. After a pre-selection phase based on scientific excellence, the six finalists each held a presentation at the EuChemS Chemistry Congress in Lisbon, Portugal. The award not only highlights the excellent contribution of Sebastian Weber to the field of chemical sciences, but promotes in front a broad audience the essential role of synchrotron radiation in delivering future insights and innovations across the field of natural sciences.

Related articles on this research can be found in the Diamond Annual Review 2021-2022, “X-ray ptychography investigates coking of solid catalysts in 3D”, p.66-67, and on the DESY website

Image: Award ceremony during the 8^th EuChemS Chemistry Congress in Lisbon, Portugal, Sebastian Weber (KIT, left), Prof. Floris Rutjes (President of the European Chemical Society, middle) and Prof. Angela Agostiano (Chair of the EYCA Award Committee, right).

Graphics: EYCA

XRM2022 Hosted Virtually by NSRRC

2022/07/052022/09/13

The International Conference on X-ray Microscopy (XRM), initiated in 1980’s, has evolved into one of the biggest and the most important meetings in the field of X-ray Microscopy. At XRM2016, the National Synchrotron Radiation Research Center (NSRRC) proposed to host the XRM2020 and stood out from the competition. Due to the COVID-19 pandemic, XRM2020 was cancelled and rescheduled to 2022.

To respond to the ongoing COVID-19 and to make it easy to attend, the XRM2022, held from June 19 to 24, ran in All-VIRTUAL mode. The online platforms used for facilitating this virtual event were Whova, Gather Town, and Webex. Whova was like a portal for not only social networking but also linking to all online oral presentations, which were livestreamed through Webex. Gather Town allowed participants to spend time with their communities just as easy as real life by making virtual interactions in a fully customizable spaces with other colleagues, poster presenters and exhibitors.

There were 328 participants from all over the world – 42% from Europe, 40% from Asia and Oceania, and 18% from America. In total, 99 posters were presented and 105 talks (6 plenary, 30 invited, and 69 contributed) were scheduled. The XRM2022 will publish post-conference proceedings. The next XRM conference will be hosted by MAX IV in 2024.

Read more on the XRM2022 website

How did birds escape from mass extinction? NSRRC discovered the secret hidden within their teeth!

2020/05/072020/09/02

The research team consists of Dr. Wang Chun-Chieh and Mr. Chiang Cheng-Cheng from the National Synchrotron Radiation Research Center (NSRRC), Dr. Li Zhiheng and academician Dr. Zhou Zhonghe from the Institute of Vertebrate Paleontology and Paleoanthropology, Prof. Huang E-Wen from the Department of Materials Science and Engineering, NCTU, and Mr. Hsiao Kiko from Mr. Fossil, spent 3 years on the research and analysis of the tooth evolution from Theropoda, a dinosaur clade that is most related to ancient birds, to ancient birds, using synchrotron Transmission X-Ray Microscopy (TXM). It is the first time in history that the research team discovered the Porous Mantle Dentin of ancient birds has deteriorated and disappeared, which confirmed that the transformation of feeding habits of birds fortunately helped them to escape from a mass extinction event. The research result was published in the international journal BMC Evolutionary Biology on April 21st.

Cretaceous–Paleogene Extinction Event

How did birds, descendants of dinosaurs, escape from the mass extinction before 65 Mya, has always puzzled scientists. When meteorites struck the earth, the already frequent volcanic eruptions led to a significant amount of dust entering the atmospheric layer, which blocked the sun and hindered photosynthesis for plants, thus induced further severe impact to the global ecosystem. When plants no longer received energy from the sun, herbivores began dying due to no food sources, which eventually led to the successive extinction of carnivores. This series of food chain collapses resulted in the extinction of 75% of organisms on earth, for which the spotlight lies on the mass extinction of non-avian dinosaurs (Birds is the only survived dinosaur lineage).

Read more on the NSRRC website

Image: Fossil specimens of Sapeornis of Avialae and Microraptor of Theropoda during early Cretaceous.

X-ray microscopy at BESSY II: Nanoparticles can change cells

2020/02/132020/02/13

Nanoparticles easily enter into cells. New insights about how they are distributed and what they do there are shown for the first time by high-resolution 3D microscopy images from BESSY II.

For example, certain nanoparticles accumulate preferentially in certain organelles of the cell. This can increase the energy costs in the cell. “The cell looks like it has just run a marathon, apparently, the cell requires energy to absorb such nanoparticles” says lead author James McNally.
Today, nanoparticles are not only in cosmetic products, but everywhere, in the air, in water, in the soil and in food. Because they are so tiny, they easily enter into the cells in our body. This is also of interest for medical applications: Nanoparticles coated with active ingredients could be specifically introduced into cells, for example to destroy cancer cells. However, there is still much to be learned about how nanoparticles are distributed in the cells, what they do there, and how these effects depend on their size and coating.

Image: 3D architecture of the cell with different organelles: mitochondria (green), lysosomes (purple), multivesicular bodies (red), endoplasmic reticulum (cream).
Credit: Burcu Kepsutlu/HZB

New optical device opens path for extreme focusing of X-rays

2019/12/022019/12/09

Adaptable refractive correctors for X-ray optics

An innovative new type of optical component for X-rays has been developed by a scientific team in the Optics and Metrology Group at Diamond Light Source. This new optical component is designed to correct for the effect of imperfections in the optical elements used for focusing of X-rays. It works by introducing a controlled change to the X-ray’s phase. It is known as an “adaptable refractive corrector” – so called because the corrector uses refraction and can adapt the correction to the unique imperfection of any optical element. The researchers have designed and tested such a component at Diamond obtaining reductions in the effect of the imperfections in a range of mirror and lens focusing optical elements by a factor of up to 7. This development is expected to have application to new developing techniques such as hard X-ray microscopy at the nanometre scale.

Image: Schematic showing the adaptable corrector with a double mirror system.

Virtual lens improves X-ray microscopy

2019/02/012019/02/21

PSI researchers are first to transfer state-of-the-art microscopy method to X-ray imaging

X-rays provide unique insights into the interior of materials, tissues, and cells. Researchers at the Paul Scherrer Institute PSI have developed a new method that makes X-ray images even better: The resolution is higher and allows more precise inferences about the properties of materials. To accomplish this, the researchers moved the lens of an X-ray microscope and recorded a number of individual images to generate, with the help of computer algorithms, the actual picture. In doing so they have, for the first time ever, transferred the principle of so-called Fourier ptychography to X-ray measurements. The results of their work, carried out at the Swiss Light Source SLS, are published in the journal Science Advances.

Image: Klaus Wakonig and Ana Diaz, together with other PSI researchers, have transferred the principle of Fourier ptychography to X-ray microscopy for the first time ever.
Credit: Paul Scherrer Institute/Markus Fischer

Shining a new light on biological cells

2018/09/072018/09/12

Combined X-ray and fluorescence microscope reveals unseen molecular details

A research team from the University of Göttingen has commissioned at the X-ray source PETRA III at DESY a worldwide unique microscope combination to gain novel insights into biological cells. The team led by Tim Salditt and Sarah Köster describes the combined X-ray and optical fluorescence microscope in the journal Nature Communications. To test the performance of the device installed at DESY’s measuring station P10, the scientists investigated heart muscle cells with their new method.

Modern light microscopy provides with ever sharper images important new insights into the interior processes of biological cells, but highest resolution is obtained only for the fraction of biomolecules which emit fluorescence light. For this purpose, small fluorescent markers have to be first attached to the molecules of interest, for example proteins or DNA. The controlled switching of the fluorescent dye in the so-called STED (stimulated emission depletion) microscope then enables highest resolution down to a few billionth of a meter, according to principle of optical switching between on- and off-state introduced by Nobel prize winner Stefan Hell from Göttingen.

Image: STED image (left) and X-ray imaging (right) of the same cardiac tissue cell from a rat. For STED, the network of actin filaments in the cell, which is important for the cell’s mechanical properties, have been labeled with a fluorescent dye. Contrast in the X-ray image, on the other hand, is directly related to the total electron density, with contributions of labeled and unlabeled molecules. By having both contrasts at hand, the structure of the cell can be imaged in a more complete manner, with the two imaging modalities “informing each other”.
Credit: University of Göttingen, M. Bernhardt et al.

Perovskites, the rising star for energy harvesting

2018/06/052018/06/18

Perovskites are promising candidates for photovoltaic cells, having reached an energy harvesting of more than 20% while it took silicon three decades to reach an equivalent. Scientists from all over the world are exploring these materials at the ESRF.

Photovoltaic (PV) panels exist in our society since several years now. The photovoltaic market is currently dominated by wafer-based photovoltaics or first generation PVs, namely the traditional crystalline silicon cells, which take a 90% of the market share.

Although silicon (Si) is an abundant material and the price of Si-PV has dropped in the past years, their manufacturing require costly facilities. In addition, their fabrication typically takes place in countries that rely on carbon-intensive forms of electricity generation (high carbon footprint).

But there is room for hope. There is a third generation of PV: those based on thin-film cells. These absorb light more efficiently and they currently take 10% of the market share.

Image: The CEA-CNRS team on ID01. From left to right: Peter Reiss, from CEA-Grenoble/INAC, Tobias Schulli from ID01, Tao Zhou from ID01, Asma Aicha Medjahed, Stephanie Pouget (both from CEA-Grenoble/INAC) and David Djurado, from the CNRS.
Credits: C. Argoud.