PETRA III (DESY) – Lightsources.org

Nanoscale under gigapressure

2025/10/292025/10/30

Research team led by DESY and MAX IV scientists adapts important X-ray analysis method for use with difficult-to-move samples

Sometimes a change of perspective can make a world of difference. A team of scientists from DESY and MAX IV as well as University of Bayreuth has rearranged the method in which one can use an X-ray beam to image a sample without using high-quality lenses. The method, called ptychography, has been widely used at synchrotrons and free-electron lasers to analyse the inner workings of materials quickly enough while avoiding major damage to the sample by the X-rays. The team has turned the standard method of ptychography on its head: Instead of moving the sample around the X-ray beam, they have figured out how to move the X-ray beam itself in a way that does not alter the properties of the X-rays while still accomplishing the effect of ptychographic analysis. Moreover, they have tested the method on a sample that is in and of itself difficult to move – short-lived states of matter under extreme conditions of pressure and temperature. The team has published their findings in the Proceedings of the U.S. National Academy of Sciences (PNAS).

X-ray ptychography has become, in recent years, a standard technique in the toolbox of researchers using X-ray light sources. In a wide variety of fields, including biology and geology, the technique has been critical for imaging the interiors of samples up to atomic-scale detail non-destructively, revealing details on a scale that methods of light and electron microscopy cannot reach. Up to now, ptychography has been accomplished by using extremely precise sample movers that would change the position of the sample relative to the X-ray beam by tiny lengths – sometimes to the nanometre level – creating a grid pattern of sequentially imaged spots that eventually revealed the full image. Called high-resolution phase-contrast imaging, it has provided insights into the nanoscale structures of tiny biological structures, mineral deposits, computer chips and much more.

Image: Two views of an extreme-states experiment: To the left is an X-ray micrograph of the sample set up, which consisted of a piece of elemental iron surrounded by solid oxygen, itself surrounded by a rhenium gasket within a diamond anvil cell creating intense pressure. To the right is a ptychographic reconstruction of the area of the sample hit by X-rays, shown with a green circle. In that area using their new ptychographic method, the team could reconstruct the oxidation of the iron being melted by the intense pressure. An extreme-states experiment of this kind has not before been imaged in this way.

Credit: Tang Li, DESY

Robust supercrystals for the LEDs of the future

2025/07/302025/08/07

Nanometre-sized crystals of perovskite offer great potential for applications in the field of light-emitting diodes, solar cells and optical switching elements. A particularly interesting arrangement occurs when a large number of these nanocrystals join to form a larger structure – a supercrystal. Researchers at the University of Tübingen have now found a novel way of achieving this. They resorted to a clever technique to produce perovskite supercrystals that are particularly stable and therefore useful. Some important analyses were carried out at DESY: Using its X-ray source PETRA III, the team managed to determine the precise structure of the supercrystals. They are now presenting their findings in the journal ACS Nano.

Perovskites, named after the Russian mineralogist Lev Perovski, are a class of crystalline materials with a characteristic lattice structure. Lead halide perovskites are particularly promising, as they can be produced relatively easily by chemical methods and have remarkable optoelectronic properties – which is why these materials are the subject of intensive research. The first practical applications now appear to be within reach: Experts are working on high-performance solar cells based on perovskites, as well as on a new generation of highly efficient LEDs and laser chips.

Perovskite nanocrystals are a particularly exciting area of research. “Their optoelectronic properties depend heavily on their size – which is typical of quantum behaviour,” explains Jonas Hiller from the University of Tübingen, one of the authors of the study. “Because of this, their properties can be specifically customised. The energy of the light they absorb or emit varies depending on their composition and their size.”

Under certain conditions, these perovskite nanocrystals can form larger structures, creating a supercrystal. “This is a crystal made up of crystals,” Hiller explains. “You can compare it to a Rubik’s Cube which is made up of several smaller cubes.” The exciting thing is that while the individual nanocrystals retain their desired quantum properties, they can be handled as a macroscopic unit and thus deployed in practical applications.

Forming a supercrystal in two phases

Until now, supercrystals like this have been created by allowing a solvent containing the perovskite to slowly evaporate. The resulting structures form very gradually on the substrate. “However, the supercrystals are produced at random sites around the substrate,” explains the project manager Ivan Zaluzhnyy from Tübingen. “Also, the individual nanocrystals are surrounded by a protective layer of organic molecules which makes the entire supercrystal very soft.” As a result, they break very easily when you try to move them around mechanically. This poses a real obstacle for applications in which the positioning of the materials is crucial, such as between two electrodes in an electrical component.

To solve this problem, the team opted for an alternative approach: two-phase diffusion. A solution containing the nanocrystals is layered on top of a second liquid: acetonitrile. This acts as an anti-solvent for the perovskite crystals. As it slowly penetrates the solution containing the nanocrystals, it gradually reduces their solubility. “This results in crystal growth beginning at the boundary surface between the two phases,” explains Jonas Hiller. The acetonitrile displaces the organic molecules coating the crystals, resulting in a firmer, more stable structure.

In order to examine the structure of these supercrystals more closely, the team used the narrow X-ray beam at GINIX, an instrument installed at the PETRA III beamline P10. “The beam diameter of just 300 nanometres makes it possible to examine different regions within a supercrystal with high precision,” explains DESY physicist Wojciech Roseker. And Jonas Hiller adds: “The extremely high quality of the diffraction data was a key element of this study. It enabled us to analyse the structure of the supercrystals in great detail.”

The team found that the supercrystals produced, typically had an area of 10 by 10 square micrometres but were significantly thicker than the comparatively flat structures that could be achieved using the old method. Their height was more than five micrometres which improves their stability. This makes the supercrystals robust enough to be gripped with micromanipulators and moved to other locations – a first for perovskite structures.

Image: Like a crystal rubik’s cube: The research team has found a way to create ordered perovskite supercrystals.

Credit: University of Tübingen, figure from original publication

New technologies for PETRA IV

2025/07/032025/07/14

Large particle accelerators are extremely complex machines. At DESY’s X-ray source PETRA III, for instance, electrons travelling close to the speed of light are stored for many hours at a time. This process requires an injector – a complex assembly of pre-accelerators that first produces the particles and then brings them up to speed before they are injected into the 2.3-kilometre PETRA III electron storage ring. For its planned successor PETRA IV, an innovative laser plasma accelerator is being developed that will inject the electrons directly into the storage ring without the detour through a pre-accelerator chain. This would save space and energy. In a recently published conceptual design report (CDR), the research centre DESY describes what such an injector might look like.

“The publication of this study is an important milestone for us,” says Alberto Martinez de la Ossa, corresponding author of the study. “We show that it is in principle possible to use a plasma injector for a high-performance source like PETRA IV and we outline the challenges that still need to be overcome.” The realization of this study was made possible by a team of scientists from two distinct communities: plasma-based and radiofrequency-based accelerators. “Closely working together has been crucial to coming up with the most promising design for the plasma injector,” adds de la Ossa.

The plasma injector is based on laser plasma acceleration which is still a relatively young technology. Instead of using powerful radio-frequency waves to accelerate the electron bunches to high energies, as in a conventional system, a laser fires short, extremely intense pulses of light into a gas-filled tube. Here, the light pulses create strong electric fields which can literally catapult electrons away. This technology allows powerful accelerating fields to be produced in a tiny space, permitting the construction of very compact accelerators. DESY has been developing and refining this technology for several years.

With the conceptual design for a PETRA IV injector, the research centre is now outlining a potential first concrete application of this pioneering technique. Currently, an electron gun generates the particle bunches for the PETRA III injector and a 70-metre linear accelerator (linac) brings them up to speed. The electrons then enter the DESY II accelerator – a ring-shaped synchrotron with a circumference of 300 metres, which accelerates the particles to their final energy of 6 GeV before sending them on to the PETRA III ring. “Using a plasma injector, we would only need a fraction of the space,” explains de la Ossa.

“The ideal version would be a small building right next to the storage ring,” adds Andreas Maier, lead scientist for plasma acceleration at DESY. “The laser could be housed on the upper floor and the plasma accelerator on the lower floor.” By connecting it directly to the ring, it would be possible to dispense with the components that are currently required to transfer the electron bunches. This, together with the plasma acceleration, could save a lot of energy.

Various innovations are being developed so that a practical injector can be built. The quality of the electron bunches is crucial – after all, PETRA IV is expected to produce significantly narrower and more intense X-rays than the current ring. To do this, the future machine requires electrons whose energy distribution fluctuates by no more than one percent. “That was probably the most fundamental challenge for a plasma injector,” explains de la Ossa, “because laser plasma accelerators tend to have a relatively broad energy spectrum.” The scientists have already overcome this hurdle. They recently developed an energy compressor, in which the plasma stage is followed by a short conventional accelerator. Thanks to a clever arrangement, the energy distribution of the electron bunches is compressed to within the required range. The concept has already been successfully implemented in a demonstrator experiment, whose results were recently published in the journal Nature.

To enable full energy direct injection into the storage ring, electrons with an energy level of 6 GeV are required. The DESY team wants to resort to a special variant of plasma acceleration and develop it further: a plasma channel guided laser plasma accelerator. In this method, a weaker light pulse is fired into a gas ahead of the actual laser pulse. This ionises the gas, turning it into a plasma and creating a channel for the main laser pulse following immediately behind it. As a result, the latter remains sharply focused over dozens of centimetres, so that it can accelerate electrons over a longer distance – and thus to higher energies. Another requirement is that, in order to allow a large number of experiments to be conducted at PETRA IV, the ring must be replenished with new electrons every few hours – which must happen as quickly as possible. To achieve this, the laser driving the future plasma injector needs to be able to fire around 10 to 30 high-intensity light pulses per second, depending on the amount of electrons each pulse carries. And finally, the laser-based system must prove that it can operate at the same level of reliability as the current, proven radio-frequency technology.

To study the complex interaction between the different technologies, DESY is able to draw on state-of-the-art computer simulations. New software was developed specifically for these studies. “Modelling the entire chain precisely – from the plasma accelerator to the PETRA IV storage ring – is a complex task, but crucial for such sophisticated studies,” says Maxence Thévenet, team leader for theory and simulations at DESY’s Plasma Acceleration Group. “Working in an open-source environment ensures high standards and promotes collaboration,” adds Thévenet.

Image: In the laser-plasma accelerator, a short, high-intensity laser (shown in yellow) generates a plasma wave (shown in white). This wave enables electron bunches (shown in blue) to be accelerated to the energy required for PETRA IV within just a few centimetres. What a laser-plasma accelerator for PETRA IV—known as a plasma injector—could look like is described in the recently published CDR.

Credit: DESY, A. Ferran Pousa, A. Martinez de la Ossa.

Nanoburgers with promising flaws

2025/06/262025/07/03

Publication in ACS Nano: DESY team finds surprising defects in tiny metal particles which could stimulate the development of more efficient catalysts

Catalysts are indispensable in many industries: they speed up chemical reactions, making them economically viable. They often consist of tiny particles, just a few nanometres across, to which molecules attach themselves, making it easier for them to form a bond with another reagent. The catalysts themselves are left unchanged. One class of nanocatalysts consists of the precious metals platinum and rhodium and is used, for example, in the purification of waste gases, in hydrogen production and in fuel cells.

The team led by DESY physicist Andreas Stierle has been studying such platinum-rhodium catalysts for quite some time. However, when they analysed the particles again using X-rays, they were surprised to find that some of the nanoparticles are not tiny, homogeneous lumps but consist of an upper and a lower half – like the two halves of a burger bun. Although the two halves are stuck together, the nature of this bond and how it affects the catalytic properties of the nanoparticles was unclear.

To work this out, Stierle’s team designed an experiment at the European Synchrotron Radiation Facility ESRF in Grenoble. ‘It produces an extremely narrow X-ray beam that can be used to study individual nanoparticles,’ explains Stierle. Specifically, the researchers used a method known as Bragg Coherent Diffraction Imaging (BCDI), in which the X-ray beam creates a special diffraction pattern as it passes through the nanoparticle, and this is recorded by a detector. ‘Special algorithms can then be used to reconstruct how the atoms are arranged in the crystal lattice and where they deviate from the regular structure – distortions, defects and dislocations in the crystal lattice,’ explains Ivan Vartanyants, who supervised the reconstructions.

What made their experiment different was that the measurements were performed while the nanocatalysts were active. The group directed a stream of carbon monoxide and oxygen to pass over the nanoparticles, on whose surface the gas was converted into CO2 – at temperatures of more than 400 degrees Celsius. ‘These experiments were extremely difficult; we had to keep the nanoparticles fixed to within ten nanometres so that the X-ray beam always illuminated the entire particle,’ explains first author Lydia Bachmann, who is studying this topic as part of her PhD. ‘To do this, we had to make sure that the conditions were absolutely steady.’

The outcome was unexpected: the experts discovered pronounced crystal defects where the upper and lower halves of the nanoburgers meet. The two boundary surfaces did not fit perfectly on top of each other; atoms were missing around the outer edges. These gaps cause all the atoms in the vicinity to shift, significantly distorting and displacing the crystal lattice.

What was truly remarkable was that these ‘flaws’ had an extremely positive effect on the catalytic properties of the nanoburgers. ‘The defects serve as unique absorption sites for molecules,’ explains co-author Thomas Keller. ‘Molecules such as oxygen adhere very well to them, which increases the effectiveness of the catalyst.’ In the future, these findings could help industry to develop more efficient and effective catalysts – through deliberate ‘defect engineering’ to create as many binding sites as possible on the nanoparticles, where molecules can be converted.

Image: The Nano-Burger in action: The two ‘halves‘ of the platinum-rhodium catalyst interact with reagents in this simulation.

Credit: Science Communication Lab for DESY

Slow iron hopping through magnetite follows one specific path

2025/06/16

An international team at DESY and the synchrotron radiation source SOLEIL in France has uncovered the special way in which iron diffuses in the near-surface region of magnetite. By using specially designed thin-films of this iron-oxide, containing the isotope ⁵⁷Fe, hopping of iron atoms through the crystal lattice was studied by nuclear forward scattering carried out at the PETRA III beamline P01. Surprisingly, the results show that most of the iron hops only through octahedral sites in the crystal lattice. Despite the uncovered low energy barrier, the diffusion process is very slow. The outcome of this study provides new insights addressing the stability of magnetite when used in various applications such as magnetic nanoparticles.

As iron-containing minerals are abundant in the Earth’s crust, iron oxides have permeated many different aspects of the world around us. Magnetite (Fe₃O₄) is a common iron ore and the oldest magnetic material known to mankind. Its magnetic properties have probably been used in compass-like instruments since the Middle Ages. At present, magnetite nanoparticles have emerged as a very promising material in medicine, either for drug delivery, imaging or cancer therapy by hyperthermia. Each of these applications makes use of magnetite’s magnetic properties: External magnetic fields can be used for steering drug-containing nano-vehicles for contrast-enhancements in magnetic resonance imaging and to destroy cancerous tumours by heating through the Joule effect.

Modern nano-fabrications techniques used to synthesise iron oxides are faced with the problem of their relative stability. It is difficult to control the formation of single-phase magnetite (Fe₃O₄) versus maghemite (γ-Fe₂O₃) and hematite (α-Fe₂O₃), as the structure and oxidation states of iron atoms of these iron oxides are slightly different. In fact, the barriers for transformation of one phase into the other are so low, that even at room-temperature over time unwanted phase transformations can take place. These can have dramatic consequences for the magnetic properties in a particular application. Even less is known about how the phase stability is affected by the surrounding atmosphere which, depending on the application, can be airy or even watery. The fundamental process for these phase transformations is the diffusion of iron within the solid-state material. To study near-surface cation diffusion, an isotopically labelled thin-film was prepared on a magnetite single crystal. The structure of similar thin-films was studied at SOLEIL beamline SixS to be able to correlate structural defects and cation diffusion. Among the different oxides, iron is directly surrounded by either four or eight oxygen atoms which are called tetrahedral and octahedral co-ordination, respectively. Being both, isotope and site selective, nuclear forward scattering at PETRA III beamline P01 showed that not only the temperature-induced diffusion is very slow, but also that it predominantly takes place in the slightly bigger octahedral sites.

Image: An isotopically labelled magnetite thin-film was prepared and temperature induced cation transport was site-selectively observed by nuclear forward scattering.

Credit: Steffen Tober, DESY

PETRA III peers deep into plant tumours

2025/04/162025/04/28

Analysis of leaf galls formed by mites show how they alter the plants’ metabolism of metals

They can be a nightmare for farmers and gardeners: galls, abnormal plant growths caused by various organisms, can damage crops and other plants. Researchers have used PETRA III to analyse galls caused by mites that infest the leaves of various trees and bushes. What they found is incredible: The mites alter the plants’ metabolism of trace metals in the newly formed galls to better suit their needs, aggregating metals needed for their nutrition and protection while sequestering the excessive ones. The results, published in the journal New Phytologist, could help scientists to better understand these evolutionarily fascinating interactions between plants and specialised herbivores and perhaps eventually help avoid damage to economically important plants.

A gall can be formed on every part of a plant: leaf, root, trunk, flower. Insects and mites can induce complex galls by hijacking the plant’s cellular functions and extensively reprogramming expression of its genes. The new tissue serves to feed and protect the gall-inducing insect or mite. The mites from the family Eriophyidae make brightly coloured, spike-shaped “nail” galls, within which they spend multiple generations from spring to autumn each year. A female mite infests the emerging leaves in springtime, and the leaf grows with galls filled with numerous male and female mites. During winter, the female mites emerging from the galls hide in winter buds to initiate another life cycle in the spring.

“The gall is a sort of ordered tumour,” says Filis Morina, a plant scientist based at the Biology Centre of the Czech Academy of Sciences in České Budĕjovice who is first author of the study. “This is like a hijacking of the plant’s cellular functions because the mite completely manipulates what happens to the leaf. The leaf otherwise would never make such a shape as a nail gall.”

Although they are essential for both the plant and the mites, the role of the metals in the interaction between the two had remained elusive. To reveal this, the authors used a technique called tomography – more commonly used in medical imaging – and the X-rays of the DESY X-ray light source PETRA III to peer into the gall.

“In scanning X-ray fluorescence tomography, you scan the sample line by line, and you rotate the sample between the lines,” says DESY scientist Gerald Falkenberg, who leads the PETRA III P06 beamline and performed the research with the team. The result is a three-dimensional see-through map of the structures and contents of the galls.

“The P06 beamline at PETRA III allowed us to look down with subcellular detail as to where elements that are decisive for the development of the mite and the gall are distributed,” says Hendrik Küpper, who led the research with Morina at the Biology Centre CAS. The team found that mites induce accumulation of zinc, iron and copper in the nutritive tissue, while manganese and calcium accumulate in large secretory cells. The mites had changed the distribution of metals as well as their function. Using complementary spectroscopic, biochemical and genetic techniques, the team could finally map different metals with gene expression, metabolic profile and oxidation–reduction reactions regulated by the mite in the gall.

To further understand the changes in manganese metabolism, the team used a technique called XANES (X-ray absorption near edge spectroscopy) tomography to get a map of manganese absorption spectra in different gall compartments. This allowed for identification and mapping of the classes of manganese-binding compounds, linking distribution of the metal and its function in individual cells in the galls.

Image: Nail galls on a leaf

Credit: Wikimedia Comms

PETRA III delivers novel approach to determine melting at high pressures

2025/02/062025/02/10

An international team of scientists from DESY Photon Science, Lawrence Livermore National Laboratory (U.S.), the University of Edinburgh (UK), and Karlsruhe Institute for Technology (Germany) has developed a novel approach to accurately determine the melting temperature of opaque materials using X-ray phase contrast imaging and X-ray diffraction in the laser-heated diamond anvil cell at up to pressures of 500 000 bar and 4000 Kelvin. The team lead by Emma Ehrenreich-Petersen from DESY and Earl Francis O’Bannon from Lawrence Livermore National Laboratory developed the technique at beamline P02.2 at DESY´s high-energy photon source PETRA III and published their results in the journal Results in Physics.

For decades, determining the high pressure melting of opaque materials has been a significant challenge. Many approaches have been developed over the last decades since the introduction of laser heated diamond anvil cell. This fist-large high-pressure device consists of two opposed modified diamonds which compress the sample in between them. It can generate pressures that are higher than the pressure found at the center of the Earth. The sample – in this case a metal foil – can be heated through the transparent diamonds with very powerful infrared lasers that illuminate the sample from both sides of the diamonds. “It is extremely difficult to detect the first appearance of very small amounts of melt by means of optical imaging or X-ray diffraction of the sample. This led to discrepancies in melt temperature determination in earlier studies,” explains lead author Emma Ehrenreich-Petersen from DESY. “In our study we combine the otherwise well-established technique of X-ray phase contrast imaging with diffraction and apply it to the laser heated diamond anvil cell, to detect the smallest amount of phase contrast between the solid and the liquid sample”

“This approach has the advantage that one does not need to melt the entire sample, since this setup can resolve features as small as about one micron” states project leader Earl Francis O’Bannon from Lawrence Livermore National Laboratory. “We benchmarked this novel approach at the PETRA III Extreme Conditions Beamline P02.2 by determining the melting line of platinum up to pressures of 500 000 atmospheres and temperatures up to 4000 Kelvin. We demonstrated that the technique is much more sensitive in determining the onset of melting than any other previous technique.”

Image: The technique developed at PETRA III allows the incipient melting process in platinum (centre) to be tracked precisely.

Credit: DESY, Hanns-Peter Liermann

Tracking the ‘medication taxis’

2024/12/052024/12/10

A team of researchers has been using the X-ray source PETRA III to visualise the spread of an anticancer drug in tumor cells

How can cancer drugs be delivered safely to their destination? An international team of researchers has been using the X-ray source PETRA III to test a technique for visualising how a drug is distributed inside tumor cells. In the future, this approach could help to develop more targeted and hence more effective cancer therapies. The working group has presented its findings in the journal Advanced Functional Materials.

Some anticancer drugs present a special challenge. They do not dissolve easily in the blood or they break down too quickly and because of this they are unable to reach the site where they are needed: the tumor. Researchers have come up with an ingenious strategy to overcome this: they enclose the drug in a molecular capsule. On being administered, this medication taxi makes its way through the body. Once it reaches the tumor, the capsule dissolves and releases the drug.

The only trouble is that it is difficult to observe how well this strategy is working. How do the drug capsules find their way into the tumor cells? And do they actually release the drug inside them? To answer these questions, researchers have until now had to label the drugs using special dyes. When a laser beam is shone at these, they light up like signal lamps and reveal the distribution of the drug inside a cell.

This method has its drawbacks, however. The markers are usually similar in size to the drug molecules themselves, and this can distort the readings. “It’s as if you were trying to track a fish through the ocean by fitting it with a transmitter that is as big as the creature itself,” explains Marvin Skiba, a PhD student in Wolfgang Parak’s group at the University of Hamburg’s Centre for Hybrid Nanostructures. “In that case, it’s doubtful whether the fish would move around in the same way as it would without the transmitter.” It would be helpful, therefore, to have a way of seeing the drug inside the medication taxi without having to label it with a dye.

One promising approach is X-ray fluorescence, a technique that can detect minute traces of a chemical element. The principle is straightforward. “When an X-ray beam strikes a sample, it excites the elements in it,” explains DESY physicist Gerald Falkenberg. “The excited atoms want to shed this energy quickly by emitting X-ray quanta. We use detectors to capture these quanta.”

The crucial point is that every element emits a different “X-ray colour”, thereby leaving its own distinctive fingerprint. The X-ray beam scans the sample line by line, creating a map of the elements. This requires a very powerful, narrow X-ray beam, such as the one generated by DESY’s X-ray source PETRA III at beamline P06.

To determine the suitability of this method for studying drugs transported in medication taxis, Skiba and Falkenberg’s team focused on a compound containing the element selenium, a potential therapeutic for treating tumors. “We enclosed the compound in a variety of different microparticles,” explains Marvin Skiba. “We then injected these into a cell culture and used X-rays to track how the selenium was distributed in the cells.”

Image: Depending on the route of administration, the intracellular distribution of the selenium-based drug changes. When non-biodegradable polymers are used as the building blocks of the capsules, the selenium remains in the container and is not released (upper picture). The situation is different when amino acid and sugar-based vehicles are used which are digested by the cell and result in intracellular redistribution of the drug (lower picture). Cells are shown in grey while selenium is pseudocoloured from blue to yellow, depending on the concentration.

Credit: DESY, Marvin Skiba

New Insights into Air Pollution Formation

2024/10/252024/11/07

A team of researchers at the Fritz Haber Institute of the Max Planck Society in Berlin, the Qatar Environment and Energy Research Institute/Hamad Bin Khalifa University, the synchrotron sources PETRA III in Hamburg and SOLEIL in Gif-sur-Yvette, the Sorbonne University in Paris, the ETH Zurich, and the PSI Center for Energy and Environmental Science have made a groundbreaking discovery in understanding how air pollution forms at the molecular level. Their investigation, published in the journal Nature Communications, sheds light on the complex chemical processes occurring at the boundary between liquids, in particular aqueous solutions, and vapor in our atmosphere.

The international study focuses on the differences of complex acid-base equilibria (i.e., the ratio between basic and acidic components) inside the bulk of a solution on one hand, and at the very interface between the solution and the surrounding vapor on the other. While it is straightforward to measure acid-base equilibria in the bulk of a solution using state-of-the art methods, determining these equilibria at the boundary between a solution and the surrounding gas phase is challenging. Even though this boundary layer is about one hundred thousand times narrower than a human hair, it plays a very important role in processes that influence air pollution and climate change. Examining the chemistry of the solution-vapor boundary on a molecular scale thus helps to develop improved models for our understanding of the fate of aerosols in the atmosphere and their influence on the global climate.

Image: Combined spectroscopy and atomistic simulations provide an improved understanding of specific molecular-level processes governing air pollution formation (Credit: FHI/MPG. The cloudy background of the image is taken from NASA’s Goddard Space Flight Center, repository image s3v-1280 (https://svs.gsfc.nasa.gov/11685/)).

Using PETRA III to watch the disabling of a penicillin killer

2024/07/292024/08/06

Scientists observe in detail the binding and formation of covalent bonds of an inhibitor to a bacterial enzyme that disables common antibiotics

Antibiotic resistance is a major and particularly in recent years growing challenge in medicine. Scientists around the world are searching for new and efficient compounds to treat bacterial infections, especially infections caused by multi-resistant bacteria. A research collaboration of scientists from DESY, University Medical Center Eppendorf (UKE) in Hamburg and Universität Hamburg performed time-resolved diffraction experiments at PETRA III to observe at near atomic resolution and at the millisecond timescale the inhibition of a bacterial enzyme that nullifies a common class of antibiotics, the β-lactams. The results have been published in Nature Communications Chemistry.

Among antibiotics, beta-lactams are the classics. Penicillin, the first commercially produced antibiotic and the related derivatives from penicillin belong to this class of pharmaceuticals. At the beginning of the 21st century, half of the antibiotics used worldwide applied were beta-lactams. However, even since the beginning of the use of penicillin, bacteria have evolved defences against antibiotics. One of the defences is an enzyme called beta-lactamase. Like a molecular pair of scissors, beta-lactamase cuts the central ring of the beta-lactam molecule and disables its antibiotic properties – allowing the bacteria to keep living.

Worldwide and for the last 20 years scientists have been searching for a way to disable beta-lactamase in an effort to directly combat antibiotic resistance. Until now, most of the candidate beta-lactamase inhibitors that have been examined have been organic compounds that mimic penicillin, allowing the inhibitor to enter the enzyme’s active site and block it. However, today’s bacteria can potentially resist these molecules after around one or two years as well. A different avenue of research has taken to using far more basic molecules to block the active site of the enzyme.

“There are new boric acid-based beta-lactamase inhibitors, and they are really potent,” says Andreas Prester, the first author of the PETRA III study and a postdoc at UKE. “For example, boron-containing compounds and drugs were developed to be used for the treatment for multiple myeloma, a form of blood cancer.” In terms of pilot investigations and a drug re-purposing approach, the research collaboration identified the potential of boron-based compounds to inhibit beta-lactamases as well. “Since then we’ve studied these inhibitors in more detail, as well as their potential to inhibit beta-lactamses,” Prester adds.

Prester and his colleagues, Markus Perbandt from Universität Hamburg, Winfried Hinrichts, an emeritus professor from the University of Greifswald, and Christian Betzel, a professor at Universität Hamburg who led the research have been among those examining the inhibition caused by boric acid in detail. Using the European XFEL and PETRA III, they examined how the boric acid binds to the enzyme. At PETRA III, the team around DESY lead scientist Henry Chapman helped assemble an experiment at the beamline P11 using a mechanism that could show at atomic resolution, like a movie, the progress of boric acid binding, in this case, to the amino acid serine within the active site. “It’s a relatively stable bond, and the boric acid then blocks the ability of the enzyme to interact with the antibiotic,” says Prester.

Image: Using PETRA III’s X-ray beam, the scientists were able to watch how boric acid inhibits the beta-lactamase enzyme.

Credit: Universitätsklinikum Hamburg-Eppendorf UKE, Andreas Prester

Possible early diagnosis of Parkinson’s disease: iron distribution in brain regions

2024/06/262024/07/02

The neurotransmitter dopamine is primarily known as the happiness hormone that controls our motivation in the brain’s reward system. However, the neurotransmitter also acts as lubricating oil for our fine motor skills and regulates the movements of our muscles. If dopamine-producing nerve cells die off, affected people experience movement disorders such as tremors or muscle stiffness. The diagnosis: Parkinson’s disease. Researchers suspect that the reason for the death of nerve cells is excessive iron concentrations in the brain.

A team of researchers from Germany and the UK has now developed a method that can be used to determine the iron concentration in the affected regions. With the participation of DESY researchers Gerald Falkenberg and Dennis Brückner, the team led by Evgeniya Kirilina from the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, was able to determine possible toxic iron concentrations from MRI (magnetic resonance imaging) measurements of cells using DESY’s brilliant X-ray light source PETRA III. The work could contribute to the development of early diagnoses for Parkinson’s disease.

Parkinson’s disease is one of the most common diseases of the nervous system, affecting around 200,000 people in Germany alone. There is currently no cure for the disease. The typical Parkinson’s symptoms are caused by damaged nerve cells in the substantia nigra, an area in the brain stem. Damaged or dead nerve cells no longer produce enough dopamine or any dopamine at all – the lack of dopamine disrupts signal transmission between the nerve cells.

Iron is required for dopamine production in the nerve cells, and the corresponding nerve cells in the substantia nigra are therefore susceptible to both iron deficiency and excessive amounts of iron. Too much intracellular iron can be toxic, leading to the degeneration and death of neurons in the substantia nigra. “Oxidative stress caused by iron is considered a possible cause of the death of dopamine-producing nerve cells,” says DESY researcher Gerald Falkenberg, head of beamline P06 at DESY’s research X-ray source PETRA III. “That is why we have been looking for methods to measure the amount and distribution of iron in the brain over the course of a person’s life.” According to Falkenberg, this should also be possible for patients in hospitals in the future.

Image: Iron deposits (red) in brain tissue: Using X-ray fluorescence measurements at DESY’s X-ray light source PETRA III, researchers were able to map the iron concentrations in nerve cells of the substantia nigra (region in the brain stem). The cell bodies (yellow) of the dopamine-producing nerve cells have a very high iron concentration.

Credit: E. Kirilina, Department of Neurophysics, MPI for Human Cognitive and Brain Sciences, Leipzig, Germany

Clays transport more water into the Earth’s interior than we thought

2024/06/012024/06/13

Nobody knows how much water is contained in the Earth’s interior. It’s 6400 kilometres from the surface to the centre, but the deepest point we can get to is mere 12 kilometres, so most estimations are based on assumptions and extrapolations about the composition of our planet’s mantle and core. A study by a research team led by Yongjae Lee from Yonsei University (South Korea), conducted at PETRA III as well as at Pohang (South Korea) and the Advanced Photons Source at Argonne National Laboratory (USA), now shows that minerals might carry more water into the Earth’s deep mantle than previously assumed.

Water affects many properties of Earth’s interior: heat, deformation, volcanic and seismic activity and more. These in turn have a direct influence on life on Earth. Knowing more precisely how water distribution across the Earth began and how it has changed over the Earth’s 4.6 billion-year history might give us clues as to how it will evolve in the future.

Experiments performed at DESY’s synchrotron facility PETRA III, PLS-II at Pohang, South Korea and the Advanced Photons Source at Argonne National Laboratory, USA demonstrated that sediment minerals from Earth’s continents called clays can significantly influence the water household of the Earth’s interior. This study was conducted as part of an effort to understand how the subduction process that sends tectonic plates down to the mantle affects the global transport and distribution of water through changes in the water content contained in minerals composing the subducting plate.

The team of scientists led by Yongjae Lee from Yonsei University (South Korea) used a heated diamond anvil cell, an experimental device that can expose material to extremely high pressures and temperatures, for experiments to simulate the path clay minerals would take in a cold subduction zone, where one tectonic plate disappears into the mantle underneath another tectonic plate. They then studied the breakdown of those clays in detail. The study published in Nature Communications concludes that clays in subducting sediments are responsible for delivering up to 22% of the total water transported into the lower mantle, which is a significant amount and helps constrain the question of how much water could be in the Earth’s deep interior in total.

When continental rocks weather and break down they eventually transform into clay minerals. “Clays are layered sheet silicates that are easily transported to the ocean via rivers and make up the top most part of the oceanic plate. When these sediments are transported via tectonic movement to the edges of the continents and dive down into the Earth’s interior via the subduction process, they are exposed to elevated pressures and temperatures,” explains Yoonah Bang, lead author and former student at Yonsei University. One of the major minerals contributing to the clays in the sediments is the alumina-carrying silicate mineral called pyrophyllite (Al₂Si₄O₁₀(OH)₂), “Using a pressure cell consisting of resistively heated diamond anvils, we are able to simulate pressures of up to some 230,000 atmospheres and temperatures of 900 degrees Celsius to mimic the subduction path pyrophyllite will take when it dives down to the lower mantle” says Bang.

In cold subduction zones like those located in the west Pacific, pyrophyllite transforms to the minerals gibbsite (Al(OH)₃) and diaspore (AlO(OH)) at a depth of some 135 kilometres. During this process, the minerals take up water from the surrounding hydrated slab and carry it down to a depth of 185 kilometres. From here sequential transformations take place to other water-bearing minerals that eventually drag the same amount of water initially contained in pyrophyllite to a depth of 700 kilometres in the lower mantle. “This shows how important it is to clearly understand the role of clay minerals during the subduction process,” explains Y. Lee, who led this work. “Our research implies that clay minerals such as pyrophyllite would have transported about 2~3% of global ocean water down to the lower mantle over 2.5 billion years.”

Image: An illustration depicting that water contained in clay minerals is transported to the lower mantle through breakdown reactions along the subducting plate

Credit: Authors/Original Publication

PETRA III helps to develop high temperature capacitive energy storage

2024/04/252024/05/22

Capacitive energy storage materials possess the advantages of high energy density and speedy charge-discharging capability. In particular, polymer-based dielectric materials for high temperature operation condition are increasingly demanded for numerous emerging applications such as electric vehicles or aerospace power conditioning. So far, a common way to improve the energy density is to incorporate wide bandgap inorganic materials or constructing complex and sophisticated copolymers. To overcome such obstacles, a team from DESY and Jilin University in Changchun (China) leveraged the intrinsic formation of nanocrystallites in semicrystalline polymers to develop a single component homopolymer-based dielectric material that can operate efficiently at high temperatures of about 200°C and high electric fields of 500 MV/m. The results were published in Angewandte Chemie, International Edition.

“The intrinsically formed polymer crystallites are usually lamellae-like with a thickness of tens of nanometers. Can these crystallites achieve the same role as the nano-fillers in those inorganic-organic composite dielectric materials? It will consist of single components which simplifies material processing and makes it easily scalable.” says Wenhan Xu, the Helmholtz-OCPC postdoctoral fellow at DESY and Jilin University. Through rational molecular structure design, he produced a semicrystalline polymer film by using poly(diarylene ether naphthylamide) (PEENA). Its high-temperature capacitive performance outperforms all commercially available dielectric polymers (e.g. polyetherimide (PEI)) measured at the reference condition of 10 Hz and 200°C.

Sodium-ion batteries: How doping works

2024/02/202024/02/22

Sodium-ion batteries still have a number of weaknesses that could be remedied by optimising the battery materials. One possibility is to dope the cathode material with foreign elements. A team from HZB and Humboldt-Universität zu Berlin has now investigated the effects of doping with Scandium and Magnesium. The scientists collected data at the X-ray sources BESSY II, PETRA III, and SOLARIS to get a complete picture and uncovered two competing mechanisms that determine the stability of the cathodes.

Lithium-ion batteries (LIB) have the highest possible energy density per kilogramme, but lithium resources are limited. Sodium, on the other hand, has a virtually unlimited supply and is the second-best option in terms of energy density. Sodium-ion batteries (SIBs) would therefore be a good alternative, especially if the weight of the batteries is not a major concern, for example in stationary energy storage systems.

However, experts are convinced that the capacity of these batteries could be significantly increased by a targeted material design of the cathodes. Cathode materials made of layered transition metal oxides with the elements nickel and manganese (NMO cathodes) are particularly promising. They form host structures in which the sodium ions are stored during discharge and released again during charging. However, there is a risk of chemical reactions which may initially improve the capacity, but ultimately degrade the cathode material through local structural changes. This has the consequence of reducing the lifetime of the sodium-ion batteries.

Image: The schematic illustration shows a sodium ion battery: The positive electrode or cathode (left) consists of layered transition metal oxides which form a host structure for sodium ions. The transition metal nickel can be replaced either by magnesium or scandium ions.

Credit: HZB

Examining written artefacts with x-rays

2023/04/272023/05/26

DESY and the Cluster of Excellence ‘Understanding Written Artefacts’ are jointly breaking new ground in the material analysis of historical written artefacts

Within a new cooperation between the Cluster of Excellence ‘Understanding Written Artefacts’ (UWA) at Universität Hamburg and the German Electron Synchrotron DESY, scientists from Hamburg are now investigating historical written artefacts at the X-ray radiation source PETRA III. The prominent advantage of X-ray investigations is that the artefacts can be examined without any destruction. As far as the examination method allows, no special sample preparation is required – the precious and unique objects thus remain intact.

Currently, there are two pilot studies underway. The first study deals with Mesopotamian cuneiform tablets. These millennia-old artefacts are an essential source for understanding this ancient, advanced civilization. However, many tablets that cannot be dated and originated are of limited value for research. DESY and UWA are investigating 36 objects from the Museum für Kunst und Gewerbe (MKG) and the Hamburg State and University Library (SUB) collections to understand the context of the origin of a tablet by analyzing the nature of the clay. The powder diffraction method was chosen for the non-destructive and basic material characterization of this investigation. In this method, all mineral grains are detected by the X-ray beam in a local area, and these thus contribute to a characteristic diffraction pattern for a specific part of the clay tablet. The diffraction pattern consists of individual diffraction reflections for each contained mineral and gives atomic-level information about the crystalline structure. With suitable software, the mineral components can be analyzed, and thus an insight into the atomic structure – as well as the quantitative composition – of these minerals can be obtained.

Image: A tsakali during the experiment

Credit: DESY, Marta mayer

Engineered wall paint could kill corona viruses

2023/03/082023/03/17

Investigation of aerosols on titanium dioxide shows promising routes to surface and air disinfection

Common wall paint could potentially be modified to kill the Corona virus and many other pathogens. This is an important finding of a study from a research team including DESY scientists on the virus-killing effect of titanium dioxide (TiO₂), a ubiquitous white pigment that is found in paints, plastic products and sunscreens. TiO₂ also has many other important applications relevant to environmental sustainability and renewable energy. The international team led by Heshmat Noei from the DESY NanoLab reports its results in the journal Applied Materials & Interfaces published by the American Chemical Society (ACS).

“Titanium dioxide is widely used as a pigment to whiten a wide range of products,” explains Noei. “But it is also a powerful catalyst in many applications such as air and water purification and self-cleaning materials. Therefore, we saw it as a promising candidate for a virus inactivating coating.” Teaming up with the group of virologist Ulrike Protzer and Greg Ebert from the research centre Helmholtz Munich and the Technische Universität München, the scientists tested titanium dioxide´s power against the corona virus. “We were the first to apply corona viruses on a titanium dioxide surface and investigate what happens,” says Noei.

Hard X-ray photoelectron spectroscopy at the PETRA III beamline P22 at DESY provides the necessary high chemical and elemental sensitivity to resolve subtle chemical changes. The research team investigated the contact process on the surface and was able to clarify that the amino acids of the corona virus spike protein attach to the titanium dioxide surface, trapping the virus and preventing it from binding to human cells. “We found that the virus adsorbs to the titanium dioxide surface and cannot detach again and will eventually be inactivated by dehydration and be denatured,” explains the paper´s main author Mona Kohantorabi from the DESY NanoLab. “Moreover, the titanium dioxide catalyses the inactivation of the virus by light. For our study we used ultraviolet light, which triggered the inactivation of the virus within 30 minutes, but we believe the catalyst can be further optimised to accelerate the inactivation and, more importantly, work under standard indoor lighting. We believe it could then be used as an antiviral coating for walls, windows and other surfaces for instance in hospitals, schools, airports, elderly homes and kindergardens.”

Image: An image taken with an atomic force microscope from the investigation: The SARS-CoV-2 particles (light) adsorb on the titanium dioxide surface. There, structural proteins are inactivated by denaturation and oxidation by light irradiation.

Credit: DESY Nanolab, Mona Kohantorabi