Shining a new light on biological cells

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.

>Read more on the PETRA III at DESY website

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.

A closer look of zink behaviour under extreme conditions

Researchers have explored the phase diagram of zinc under high pressure and high temperature conditions, finding evidence of a change in its structural behaviour at 10 GPa. Experiments profited from the brightness of synchrotron light at ALBA and Diamond.

These results can help to understand the processes and phenomena happening in the Earth’s interior.

The field of materials science studies the properties and processes of solids to understand and discover their performances. Synchrotron light techniques permit to analyse these materials at extreme conditions (high pressure and high temperature), getting new details and a deep knowledge of them.

Studying the melting behaviours of terrestrial elements and materials at extreme conditions, researchers can understand the phenomena taking place inside them. This information is of great value for discovering how these materials react in the inner core of Earth but also for other industrial applications. Zinc is one of the most abundant elements in Earth’s crust and is used in multiple areas such as construction, ship-building or automobile.

>Read more on the ALBA website

Figure: P-T phase diagram of zinc for P<16 GPa and T<1600K. Square data points correspond to the X-ray diffraction measurements. Solid squares are used for the low pressure hexagonal phase (hcp) and empty symbols for the high pressure hexagonal phase (hcp’). White, red and black circles are melting points from previous studies reported in the literature. The triangles are melting points obtained in the present laser-heating measurements. In the onset of the figure is shown the custom-built vacuum vessel for resistively-heated membrane-type DAC used in the experiments at the ALBA Synchrotron. 

Nanoparticles form supercrystals under pressure

Investigations at Diamond may lead to easier ways to synthesise nanoparticle supercrystals

Self-assembly and crystallisation of nanoparticles (NPs) is generally a complex process, based on the evaporation or precipitation of NP-building blocks. Obtaining high-quality supercrystals is slow, dependent on forming and maintaining homogenous crystallisation conditions. Recent studies have used applied pressure as a homogeneous method to induce various structural transformations and phase transitions in pre-ordered nanoparticle assemblies. Now, in work recently published in the Journal of Physical Chemistry Letters, a team of German researchers studying solutions of gold nanoparticles coated with poly(ethylene glycol)- (PEG-) based ligands has discovered that supercrystals can be induced to form rapidly within the whole suspension.

>Read more on the Diamond Light Source website

Figure: 2D SAXS patterns of PEG-coated gold nanoparticles (AuNP) with 2 M CsCl added at different pressures. Left: 1 bar; Middle: 4000 bar; Right: After pressure release at 1 bar. The scheme on top illustrates the structural assembly of the coated AuNPs at different pressures: At 1 bar, the particle ensemble is in an amorphous, liquid state. Upon reaching the crystallization pressure, face-centred cubic crystallites are formed by the AuNPs. After pressure release, the AuNPs return to the liquid state. 

Yves Petroff takes over as Director of the LNLS

French physicist was Director-General of the largest European synchrotron between 1993 and 2001 and LNLS’ Scientific Director from 2009 to 2013.

In ceremony held on the morning of August 29th, Yves Pierre Petroff became Director of the Brazilian Synchrotron Light Laboratory (LNLS). Yves Petroff was LNLS’ Scientific Director from November 2009 to March 2013. During the ceremony, Rogério Cesar de Cerqueira Leite, Chairman of the Board of Directors of CNPEM, and Antonio José Roque da Silva, CNPEM’s Director-General and former LNLS Director, highlighted Pretroff’s competence and his history within LNLS.

Yves Petroff is one of the world’s leading specialists in the use of synchrotron light. He received his doctorate in physics from the Ecole Normale Supèrieure of the University of Paris in 1970. Later, he went to the University of California, Berkeley, from 1971 to 1975. During this period, Yves Petroff worked on the investigation of optical properties of solids, having made important developments in the area of Resonant Raman Effect.

In the early 1970s, the first generation of synchrotron accelerators began to be built, focused primarily on particle physics. In 1975, Yves Petroff returned to France to work in the ACO, one of the first synchrotrons in the world, located in Orsay. Pioneering work was performed by Petroff’s team on the use of synchrotron light to understand the properties of solids. His group was also the first in the world to build a Free Electron Laser in the region of visible light.

>Read more on the Brzilian Synchrotron LIght Laboratory (LNLS) website.

>Read also an article published on the ESRF website.


European XFEL celebrates one year of user operation

At the beginning of September, staff and users of the world’s largest X-ray laser facility celebrate a successful first year of user operation.

Since September 2017, over 500 scientists from more than 20 countries from across the globe have visited European XFEL in Schenefeld in north Germany for their week long experiments. The first research results were published just days ago on 28 August; more publications are in preparation for the following weeks.

For the first and second round of experiments scheduled from September 2017 to October 2018, 123 international groups of scientists submitted their proposals for experiment. Of these, 26 groups were selected by an international panel of experts to carry out their research at the two instruments—the SPB/SFX instrument (Single Particles, Clusters and Biomolecules / Serial Femtosecond Crystallography) and the FXE instrument (Femtosecond X-Ray Experiments). The experiments range from method development to biomolecule structure determination and studies of extremely fast processes in small molecules and chemical reactions. Submissions for the user experiments at the remaining four instruments scheduled to start operation between the end of 2018 and mid-2019 are currently being evaluated.

>Read more on the European XFEL website

Image: The European XFEL birthday cake shows the map of the underground tunnel system. It was cut by Nicole Elleuche (Administrative Director European XFEL), Robert Feidenhans’l (Managing Director European XFEL), as well as Maria Faury (Chair of the European XFEL Council) and distributed to European XFEL and DESY staff. 

Thailand is planning to build its ‘second’ Synchrotron Light Source

Synchrotron light source is the national infrastructure in science and technology for its contribution of research analysis from downstream, midstream, to upstream levels. Being an effective tool for advanced research, synchrotron promotes research targeting industrial applications for product development and innovation.

Thailand’s synchrotron radiation facility, the 2nd generation synchrotron light source, generates electron beam energy at 1.2 GeV covering spectral range from infrared to low-energy X-Rays. With such energy, the capacity of industrial and medical research is restricted due to the necessity of wider research techniques requiring higher energy and intensity of light. To produce high-energy X-Rays, Thailand should be compelled to develop the 4th generation of synchrotron light source with 2.5 times higher electron energy and 100,000 times higher intensity. This improvement aim to enhance research framework and facility service of Thailand to the leading position in medical, industrial, material, agricultural, food, and commercial research, including application and basic research, as well as becoming one of the top leaders in science and technology of Asia Pacific continent.

>Read more on the website of the Synchrotron Light Research Institute

Image: Architectural model of Thailand’s future second Synchrotron Light Source