2024 – A truly remarkable year for MAX IV

2024 – A truly remarkable year for MAX IV

Scientific output continued to increase at MAX IV during 2024, with the facility making societal contributions within areas such as life science, energy and materials science.

Delve into the results now published in our MAX IV Annual Report 2024.

Several factors converged to make 2024 a success. Some beamlines recently completed their commissioning phase and are now approaching full operation. MAX IV’s status as the first fully operational fourth-generation synchrotron continues to draw international users—particularly with other facilities still in upgrade cycles. The MAX IV 36th User Meeting, held in mid-January further highlighted this momentum, offering a dynamic mix of early-career researchers, dedicated sessions from other large-scale infrastructures, and active dialogue on industrial R&D needs. The enthusiastic atmosphere and record-high participation exemplify the diverse and growing academic and industrial communities that MAX IV serves.

Across the facility, the beamlines have proven more versatile than originally imagined, with life science experiments expanding into stations never intended for them, and proprietary beamtime breaking records, which now exceeds 1000 hours. Much of this proprietary use was driven by the pharmaceutical industry, but our organisation also observes growing interest from other sectors, reflecting a broader trend of industrial users seeking advanced characterisation methods.

Publications increased with 27 percent compared to 2023, and studies published during the year build on data from MAX IV in a broad range of scientific disciplines. Examples of studies from MAX IV users included research on climate effects of airbound particles, sustainable energy sources, exciting new types of electronics, battery development to meet increasing energy storage needs, catalysts for transforming unwanted substances into useful ones, to solutions for cleaning polluted soil and water, more durable and lighter materials for transport, understanding diseases that lack a cure today, and new medicines.

Read more on MAX IV website

A Greener Route to Gold Nanoparticles

A Greener Route to Gold Nanoparticles

High-resolution scanning transmission electron microscopy confirms a new, mild approach to metal nanoparticle synthesis

Gold nanoparticles (NPs) are used in a variety of applications including catalysis, drug delivery, biosensing, and electronics. Traditional methods for producing gold NPs often involve harsh conditions and tend to produce larger NPs (10-200 nm). Smaller gold NPs (less than 10 nm) are more desirable for catalysis, because their higher surface area to volume ratio offers a higher number of catalytically active surface sites, and hence greater reactivity. There is, therefore, a need to develop more sustainable methods of synthesising metal nanoparticles that allow precise control over their size and shape. However, bio-based synthesis methods using plant extracts or microorganisms often result in poor uniformity. In addition, there is a lack of sustainable methods for synthesising core-shell NPs, which are composed of two or more materials. In work recently published in Angewandte Chemie, researchers from the University of Oxford demonstrated a mild synthesis method that produced NPs with high uniformity of size and shape. Using high-resolution scanning transmission electron microscopy (HR-STEM) at the electron Physical Science Imaging Centre (ePSIC), they showed that the synthesis could also form core-shell Au@Pt nanoparticles. Their results suggest that this approach could be used to develop a new type of self-synthesised chemo-biocatalyst with wide-ranging applications in biotechnology.

Overcoming challenges in green nanoparticle synthesis

Metal nanoparticles have a wide variety of uses, from drug delivery to catalysis. Smaller NPs are more desirable for catalysis due to their greater reactivity, and gold is often combined with platinum group metals in core-shell NPs to improve reactivity and stability. As traditional synthesis methods rely on harmful chemicals or high temperatures, there is a need to develop more sustainable processes. However, bio-based strategies using plant extracts or micro-organisms struggle to produce NPs with the high uniformity required.

In this work, a research team from the University of Oxford developed a more sustainable method for synthesising metal nanoparticles using an isolated enzyme, NAD+ reductase (NRase), to achieve better control over size, shape, and catalytic activity.

They used NRase to reduce gold (Au) salts, in a process that involves the oxidation of NADH at the enzyme’s active site, which releases electrons used for the reduction of the metal salts. The new process resulted in the formation of highly uniform, spherical gold nanoparticles. By varying the concentration of NRase, the researchers were able to precisely control the size of the resulting nanoparticles; higher concentrations of NRase led to smaller nanoparticles, indicating that the enzyme acts as a template for nanoparticle formation.

The team was also able to use the process to synthesise core-shell NPs. After forming a gold NP, they found that adding platinum salts and more NADH resulted in the deposition of a platinum (Pt) shell over the gold core.

HR-STEM confirms nanoparticle structures

The team used several imaging techniques to characterise the synthesised nanoparticles, including UV and visible light spectroscopy to monitor the formation of nanoparticles and to estimate their average diameter and transmission electron microscopy (TEM) to directly observe the size, shape, and structure of the nanoparticles. Using HR-STEM at ePSIC allowed them to confirm the core-shell structure of Au@Pt NPs, with the results showing a higher ratio of platinum in the outer layers and gold (Au) in the centre.

Christopher Allen, Principal Electron Microscopist at ePSIC commented:

At ePSIC, the ability to simultaneously acquire atomic resolution images – which tells us where the atoms are – with energy dispersive X-ray spectroscopy – which tells us what the atoms are – is an incredibly powerful tool. This enables us to develop a fundamental understanding of the chemistry that is occurring during a catalytic process, which in turn can help us to develop increasingly efficient catalyst materials. The work by Professor Vincent’s group at ePSIC is a great example of how information about atomic structure can enable us to understand the macroscopic properties of materials.

Read more on Diamond website

First official users at FaXToR

First official users at FaXToR

The new beamline of the ALBA Synchrotron, devoted to fast X-ray tomography and radiography, is in full swing. It has recently welcomed the first official users with an experiment on the durability of green cements. They are scientists from the Universitat Politècnica de Catalunya and the Universitat de Barcelona investigating on new methods to find more sustainable cements.

Building a new beamline is a highly complex project that covers several critical phases, from the design to the construction, to the team recruitment and the commissioning, until you achieve a high-performance analytical instrument, ready for the scientific community. This is the result of a period that can go from 3 to 5 years approximately, including countless hours of dedication from the scientific and technical teams involved. Therefore, hosting the first official experiment is a milestone that deserves huge celebration.

FaXToR is a versatile beamline to perform quasi-real-time 3D computed tomography, being key to study the dynamics of certain processes at the micrometric scale using X-rays. It serves a wide range of scientific fields, including materials science, biology, paleontology, earth sciences, cultural heritage and industrial applications.

After its successful commissioning and the friendly users’ experiments, now FaXToR is in operation having welcomed the first official users recently. Researchers from the department of Architecture and Civil Engineering from the Universitat Politènica de Barcelona and from the department of Mineralogy, Petrology and Applied Geology from the Universitat de Barcelona have studied the properties and performance of different novel low-carbon cements at the new ALBA beamline.

The new products can result in more environmentally friendly constructions, helping to reduce the carbon footprint of the global building industry. The cement industry is responsible for approximately 5% of global carbon dioxide output and concrete is the second most consumed substance on Earth, surpassed only by water.

Read more on ALBA website

Image: Group picture including first official users at FaXToR and members of the beamline

Mapping the Quantum Landscape of Electrons in Solids

Mapping the Quantum Landscape of Electrons in Solids

SCIENTIFIC ACHIEVEMENT

Using data from the Advanced Light Source (ALS), researchers found a way to reconstruct quantum geometric tensors (QGTs)—mathematical entities that encode how an electron’s wave function is shaped by its quantum environment.

SIGNIFICANCE AND IMPACT

The mapping of QGTs enables the discovery and control of novel quantum phenomena such as superconductivity and unconventional electronic phases.

Toward a second quantum revolution

The development of quantum mechanics—featuring concepts such as quantized energy levels, wave-particle duality, and the uncertainty principle—revolutionized physics in the early 20th century. It led to the rise of the wave function as a way to describe, mathematically, the quantum state of a system (such as electrons in a crystal).

A more recent development, the quantum geometric tensor (QGT) is also a mathematical entity, this time describing how wave functions are affected by changes in a material’s quantum “landscape” (e.g., the material’s structure, its topological properties, electron-electron interactions, and spin-orbit coupling). The QGT is therefore a fundamental physical concept that helps explain a range of quantum phenomena in materials. However, despite its importance, a generic method for measuring the QGT in solids has been lacking.

In this work, researchers outline a way to measure the momentum-resolved QGT of solids using angle-resolved photoemission spectroscopy (ARPES). In addition to being fundamentally interesting, the QGT is also important for potential applications in next-generation microelectronics and advanced energy technologies. Studies involving the QGT will contribute immensely to what’s been dubbed the “second quantum revolution,” focusing on the control and harnessing of quantum nature at the device scale.

Introducing the quasi-QGT

Previously, the tools available for determining the QGT could only measure momentum-integrated phenomena, which are summed over all electron momenta. However, the QGT is, by definition, momentum resolved. To overcome this problem, a collaboration—primarily between theorists from Seoul National University and experimentalists from Massachusetts Institute of Technology (MIT)—introduced a quasi-QGT that is proportional to the QGT in two-band systems and an excellent approximation in multiband systems.

Like the QGT, the quasi-QGT is a complex quantity with real and imaginary parts. However, unlike the QGT, the real and imaginary parts of the quasi-QGT correspond to quantities measurable using ARPES: the momentum-resolved effective mass of electrons (i.e., the band Drude weight) for the real part, and the orbital angular momentum (OAM) of photoemitted electrons for the imaginary part.

Read more on ALS website

Image: The curvature of the surface where it touches the sphere depicts one aspect of an electron’s quantum landscape: the momentum-resolved effective mass of electrons in a solid. In this work, researchers established that measurements of this quantity plus the orbital angular momentum of photoemitted electrons—both accessible using angle-resolved photoemission spectroscopy (ARPES)—enable the experimental reconstruction of the QGT. The sphere is shown as a local approximation to the curvature of the surface.

Credit: Comin lab/MIT

The Secret to Drought Tolerance Lies in a Lilac Crypt

The Secret to Drought Tolerance Lies in a Lilac Crypt

Growing in the wild and in gardens, from Humboldt forests all the way to San Diego chaparral, the California lilac is a plant genus divided into two groups, Ceanothus and Cerastes. Ceanothus are associated with moister climates, whereas Cerastes have adaptations for surviving drier conditions. While both categories have stomata, pores that open and close to regulate CO2 intake, Cerastes pores have a special configuration—they’re housed in leaf indentations called stomatal crypts.

“Stomatal crypts are very rare among plants,” said Joseph Zailaa, Yale doctoral student and the corresponding author on a study of the California lilac. “This anatomical structure is thought to help provide drought tolerance.”

Using Beamline 8.3.2 at the Advanced Light Source (ALS), his research team has now uncovered secrets from the Cerastes crypts. “Classic microscopy techniques only give us a 2D picture of the leaf’s internal structure,” said Zailaa, “but microtomography at the ALS allowed us to image and view these crypts in three dimensions for the first time.” They also obtained 3D models of hydrated and dehydrated samples, allowing the researchers to observe the plants’ responses to drought.

Many arid-climate plants are drought tolerant. “They maintain functions such as water transport and photosynthesis despite the onset of drought, which uses up the plant’s water reserves,” Zailaa explained. California lilacs have developed an additional adaptation: drought avoidance. “Their stomata close and they shut down most of their function at the onset of drought to conserve water reserves,” Zailaa described. “This delays the plant from experiencing damage caused by excessive dehydration,” he added. His team’s work showed how stomatal crypts provide even further benefits to Cerastes. The researchers found that Cerastes had greater water storage capacity and water use efficiency than Ceanothus.

Read more on ALS website

Image: Ceanothus megacarpus is a member of the Cerastes subgroup of California lilacs. This species has a characteristic associated only with Cerastes, the stomatal crypts. In this 3D visualization obtained at ALS Beamline 8.3.2, white arrows indicate stomata, which are found exclusively within the crypts, or indentations in the leaf. The stomatal crypts help Cerastes species survive drought. Scale bar is 200 µm.

Credit: Craig Brodersen and Joseph Zailaa/Yale School of the Environment; Leila Fletcher/Southern Oregon University Biology Department

Improving steel pipelines for safe transport of hydrogen

Improving steel pipelines for safe transport of hydrogen

USask researchers use synchrotron light to capture 3D images of cracks that form inside steel.

Hydrogen is increasingly gaining attention as a promising energy source for a cleaner, more sustainable future. Using hydrogen to meet the energy demands for large-scale applications such as utility infrastructure will require transporting large volumes via existing pipelines designed for natural gas.

But there’s a catch. Hydrogen can weaken the steel that these pipelines are made of. When hydrogen atoms enter the steel, they diffuse into its microstructure and can cause the metal to become brittle, making it more susceptible to cracking. Hydrogen can be introduced into the steel during manufacturing, or while the pipeline is in service transporting oil and gas.

To better understand this problem, researcher Tonye Jack used the Canadian Light Source (CLS) at the University of Saskatchewan (USask) to capture a 3D view of the cracks formed in steels. Researchers have previously relied on two-dimensional imaging techniques, which don’t provide the same rich detail made possible with synchrotron radiation.

Tonye, a PhD candidate in USask’s Department of Mechanical Engineering, and his colleagues studied different pipeline steels and showed that microstructure plays a critical role in how much hydrogen the steel absorbs and how it is distributed in the metal. Their research also revealed that when hydrogen enters the steel while the pipeline is in service, it causes more damage than if introduced during manufacturing or other pre-charging conditions.

The risk of steel failure due to hydrogen embrittlement depends on several factors such as the amount of hydrogen in the steel, the steel’s microstructure, stress conditions, and operating environment. However, Tonye emphasizes that how much hydrogen is retained in the steel and where it accumulates largely dictates its failure behavior.

“We need to know the mechanism of failure and how to mitigate it,” he says.

While catastrophic pipeline failures are rare, his team’s findings are important as industries plan to transport hydrogen gas using high-strength natural gas pipelines. “These findings can help inform the production of safer pipelines,” he says. By refining the microstructure, manufacturers can design steels that are more resistant to cracking and hydrogen embrittlement.

Read more on CLS website

Unlocking the secrets of hafnia: a new era in ferroelectric materials

Unlocking the secrets of hafnia: a new era in ferroelectric materials

Depth-resolved X-ray Photoelectron Spectroscopy probes the link between polarisation and electrochemistry

Ferroelectric materials exhibit a unique property called spontaneous polarisation. Their built-in electric dipole moment can be switched between different directions by applying an external electric field. This makes them incredibly useful for a wide range of applications, including memory storage devices, sensors, and energy harvesters. The discovery of ferroelectricity in nanoscale hafnia-based films has spurred extensive research to understand its origin and unlock its full potential. Hafnia displays unusual behaviour in that its ferroelectricity becomes stronger as the material gets thinner, and one theory suggests that the electrochemical state within the hafnia film is directly linked to its polarisation and responsible for the unique size-dependent properties.

In work recently published in Advanced Materials, researchers from the University of Cambridge used depth-resolved X-ray Photoelectron Spectroscopy (XPS) at Diamond’s I09 beamline to investigate the intricate relationship between polarisation and electrochemical changes in hafnia-based ferroelectrics. The results suggest that the electrochemical state is not directly linked to polarisation, and that certain dopants can suppress the electrochemical changes that cause degradation without sacrificing polarisation, opening up exciting possibilities for engineering more robust and reliable ferroelectric devices.

Surprising findings in nanoscale hafnia films

The research team focused on two specific compositions, Hf0.5Zr0.5O2 (HZO) and Hf0.88La0.04Ta0.08O2(HLTO), both in the form of single-phase epitaxial films. These films were chosen to minimise the influence of grain boundaries and other structural complexities that could complicate the analysis. The first step was to meticulously characterise the structure and ferroelectric properties of the HLTO and HZO films using a combination of techniques. They used X-ray Diffraction (XRD) to determine the crystallographic phase and orientation of the films, Piezoresponse Force Spectroscopy (PFS) and Microscopy (PFM) to confirm the presence of ferroelectricity and visualise the domain structure and Positive-Up Negative-Down (PUND) measurements to measure the remnant polarisation and coercive field, key parameters describing the ferroelectric behaviour.

These initial characterisations confirmed the presence of the desired ferroelectric phases in both HLTO and HZO and identified 24 areas on the samples, two sets of each specific polarisation state (P-up, P-down, or as-grown), to analyse using depth-resolved XPS.

Dr Nives Strkalj explained:

Our hafnia samples were intended to be very similar in terms of polarisation, but we were expecting to see changes in their electrochemistry when we used an electric field to change the polarisation. We opted for the I09 beamline because it’s a unique setting where you can change between X-rays that probe deep and shallow with just the click of a button. Usually, if you want to probe depth, you have to realign the incidence angle, then you have to realign the detector, and it’s very time consuming. We had to check many areas of our samples, areas which were P-up, or which were P-down, and on I09 we can get depth probing very quickly.

During the XPS experiments, the researchers discovered a surprising difference in the electrochemical behaviour between HLTO and HZO. In the P-up state, HLTO showed an increase in non-lattice oxygen (NL-O) primarily at the surface, suggesting that the electric field was driving oxygen species from the atmosphere onto the film. In contrast, HZO displayed an increase in NL-O distributed throughout the bulk of the film, accompanied by reduction of the Hf and Zr cations. These findings suggest that the polarisation state is not solely responsible for the changes in oxygen electrochemistry in these materials. Instead, the electric field used to switch the polarisation plays a crucial role.

Read more on Diamond website

A lighter, smarter magnetoreceptive electronic skin

A lighter, smarter magnetoreceptive electronic skin

Novel e-skins unlock a new level of interaction between humans and machines

Imagine navigating a virtual reality with contact lenses or operating your smartphone under water: This and more could soon be a reality thanks to innovative e-skins. A research team led by the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has developed an electronic skin that detects and precisely tracks magnetic fields with a single global sensor. This artificial skin is not only light, transparent and permeable, but also mimics the interactions of real skin and the brain, as the team reports in the journal Nature Communications

Originally developed for robotics, e-skins imitate the properties of real skin. They can give robots a sense of touch or replace lost senses in humans. Some can even detect chemical substances or magnetic fields. But the technology also has its limits. Highly functional e-skins are often impractical because they rely on extensive electronics and large batteries. “Previous technologies have used numerous individual sensors and transistors to localize sources of a magnetic field, similar to touch sensors in a smartphone display. Our idea was to develop a more energy-efficient system that is more akin to our soft human skin and thus better suited for humans,” says Denys Makarov from the Institute of Ion Beam Physics and Materials Research at HZDR.

Lighter, more flexible, smarter

The researchers therefore replaced rigid, bulky substrates that usually host electronics with a thin, light, and flexible membrane that is just a few micrometers thick. The entire membrane is optically transparent and perforated, making the artificial skin permeable to air and moisture, allowing the real skin underneath to breathe.

However, such an ultra-thin membrane can accommodate a limited amount of electronic components. This is why novel e-skins feature a magnetosensitive functional layer, which acts as a global sensor surface to precisely localize the origin of magnetic signals. Since magnetic fields alter the electrical resistance of the material, a central analysis unit is able to calculate the signal location based on these changes. This not only emulates the functioning of real skin but also saves energy.

Artificial skin for a near-human sensory experience

“Such large-area magnetosensitive smart skins are a novelty,” says Pavlo Makushko, PhD student at HZDR and first author of the study. “Conceptually, e-skins now work more like the human body. No matter where I touch real skin, the signal always travels though nerves to the brain, which processes the signal and registers the point of contact. Our e-skins also have a single global sensor surface – just like our skin. And one single central processing unit reconstructs the signal – just like our brain.

This is made possible by tomography, a method that is also used for medical MRI or CT scans. It reconstructs the position of a signal from a large number of individual images. This technology is new for e-skins with magnetic field sensors – it was previously considered too insensitive for a low signal contrast of conventional magnetosensitive materials. The fact that we validated this method experimentally is a major technical achievement of the work, as Makushko emphasizes.

Read more on HZDR website

Image: Transparent magnetoreceptive e-skins for spatially continuous sensing over large areas.

Credit: Bild: P. Makushko / HZDR

Catalysis research with the X-ray microscope at BESSY II

Catalysis research with the X-ray microscope at BESSY II

Contrary to what we learned at school, some catalysts do change during the reaction: for example, certain electrocatalysts can change their structure and composition during the reaction when an electric field is applied. The X-ray microscope TXM at BESSY II in Berlin is a unique tool for studying such changes in detail. The results help to develop innovative catalysts for a wide range of applications. One example was recently published in Nature Materials. It involved the synthesis of ammonia from waste nitrates.

Ammonia (NH3) is a basic component of fertilisers and is critical to agricultural productivity around the world. Until now, ammonia has been synthesised industrially using the Haber-Bosch process, which is energy intensive and produces significant amounts of greenhouse gases that drive climate change. With the development of alternative methods, ammonia could be produced with significantly lower greenhouse gas emissions.

Better catalysts reduce emissions for Ammonia production

There are some promising approaches. For example, a team at the Fritz Haber Institute has been investigating a catalyst based on nanocrystalline copper oxide. During the catalytic reaction, an increasing proportion of these nanocrystals transformed into metallic particles of pure copper. The morphological changes were documented under the transmission electron microscope (TEM), but to gain insights into the chemical processes during the reaction, the FHI team collaborated with the group of Prof. Gerd Schneider at HZB.

Read more on HZB website

Creating circuit diagrams of the brain

Creating circuit diagrams of the brain

Adrian Wanner aims to map the brain’s architecture. Doing this will allow us to better understand neurodegenerative diseases like Alzheimer’s.

Do you know this situation? You are standing in the kitchen and suddenly don’t remember why you went in there in the first place. Working memory is at fault here. It is supposed to keep information available for us for a period of several minutes. “If it isn’t working properly, it can lead to situations just like this one, where you forget whatever it was you wanted to do,” explains Adrian Wanner, a neurobiologist at the Laboratory of Nanoscale Biology at the PSI Center for Life Sciences (CLS).

In everyday life, situations like this might be unpleasant, but tend to be ultimately harmless. For some people, however, they may indicate a more serious underlying issue, as Adrian Wanner explains: “In the case of Alzheimer’s, working memory is often the first thing to be affected. Long before pathological changes like protein deposits in the brain become clearly visible, patients experience this type of forgetfulness.” Understanding working memory and its structure in detail could thus contribute to better comprehension of the terminal illness Alzheimer’s.

Activity maps and circuit diagrams

In order to reconstruct what exactly happens when the working memory keeps information available, Wanner uses two methods. “First, we create activity maps of brain cells,” the neurobiologist explains. “In these diagrams, the neurons that are activated by a particular action light up in colour.” 

The researchers then try to find out how the individual neurons in this area are linked. “It’s like a circuit diagram for a computer,” says Wanner – but with biological synapses instead of electrical connections. Most brain regions and functions have not yet been mapped by way of such a circuit diagram that describes how information is processed: “Does information go directly from point A to point B to point C or are there cross connections or feedback loops in between that move it a step back?” 

There are various, often conflicting theories on which paths the brain activates when it processes and then stores information. Adrian Wanner wants to use empirical data to determine which model best reflects reality. He wants to observe which neurons are active during tasks for which working memory is important. He then maps the way in which these neurons are interlinked to create a detailed circuit diagram. “This way, we can track exactly what is happening in the brain at this point in time.”

The working memory at work

For his research, Adrian Wanner works with mice. “In terms of structure and function, their brains are similar to those of humans’,” he explains. “This is why they can also develop forms of dementia and we can analyse how healthy animals differ from sick ones.”

In order to analyse a mouse’s working memory, the neurobiologist sets it a task where the mouse has to remember information for a few seconds. First, the mouse learns how to move around in a virtual environment, similar to a computer game. To do this, the animal watches a screen and runs along a virtual corridor. At the beginning of the corridor, the mouse is shown a specific pattern, for example a checkerboard pattern. It must then remember this pattern. 

After a few metres, the corridor forks into a left-hand and a right-hand path. Once the mouse arrives at this point, a pattern is displayed at each path, a line pattern on the right and a checkerboard pattern on the left, for instance. Now, the mouse has to recall: “Aha! There was also a checkerboard pattern at the beginning of the corridor.” If it turns left at the virtual fork, it receives a real reward in the form of food. “It is precisely during this period, when the mouse is no longer looking at the pattern and is running along the corridor, that it must keep the information available – its working memory is active.”

While the mouse is playing this memory game, Wanner and his team are imaging the activity in its brain. By comparing these images to circuit diagrams of the brain, they can determine the rules according to which the neurons are linked in order to keep this piece of information in working memory. “In fact, brain activity differs depending on the pattern that we show the mouse. A checkerboard pattern causes different cells to activate in a different sequence than a line pattern.”

Read more on PSI website

Image: Tiny section of a mouse brain: a few dozen nerve cells with their synapses are shown, and thus only a fraction of the 100 000 cells that cavort in a cubic millimetre of brain.

Credit: MICrONs Consortium et al.

Advanced materials research in microgravity earns NASA recognition

Advanced materials research in microgravity earns NASA recognition

Key Points

  • Collaborative research has advanced an understanding of how colloidal clusters form and behave in microgravity
  • The microgravity environment aboard the ISS minimised sedimentation and convection, providing a unique opportunity to observe the pure self-assembly of particles with unique optical properties
  • Structural analyses were later conducted using neutron scattering instruments at the Australian Centre for Neutron Scattering

A pioneering study led by Professor Junpei Yamanaka of Nagoya City University and an international team that included ANSTO has delivered transformative insights into the behaviour of colloidal particles under microgravity. 

Conducted aboard the International Space Station (ISS), this research has not only been prominently featured in NASA’s 2024 Annual Highlights of Results from the International Space Station Science but also promises to reshape future material technologies—including revolutionary optical devices and even the elusive cloaking devices reminiscent of science fiction.

Colloidal clusters—aggregates of nano- and micrometre-sized particles suspended in a fluid—play a pivotal role in various industrial and scientific applications. 

“On Earth, gravity-induced effects, such as sedimentation and convection, can obscure the intrinsic properties of these clusters, hindering our ability to study their natural assembly,” explained Principal Instrument Scientist Assoc Professor Jitendra Mata at ANSTO’s Australian Centre for Neutron Scattering. 

“However, the microgravity environment aboard the ISS minimises these disturbances, providing a unique opportunity to observe the pure self-assembly of particles.”

In a specialised experimental setup, the research team mixed oppositely charged colloidal particles in an aqueous solution, allowing them to cluster in of the absence of gravity, providing opportunity to understand fundamental science of association. 

Once these structures were formed, they were immobilised in a gel using ultraviolet (UV) light curing—a process that preserved the delicate architecture of the clusters for subsequent analysis back on Earth. 

Optical microscopy revealed that even minimal gravitational effects post-return can significantly influence the formation of colloidal structures, underscoring the value of space-based research.

This landmark research exemplifies robust international collaboration. The groundwork for the experiments began in Japan in 2018, with critical contributions from Nagoya City University, Japan Space Forum, Advance Engineering Services, and the Japan Aerospace Exploration Agency (JAXA). 

Structural analyses were later conducted in partnership with A/Prof Mata using the Small-angle neutron scattering instrument Quokka and Ultra-small neutron scattering instrument Kookaburra.

“This collaboration has been instrumental in advancing our understanding of how colloidal clusters form and behave in microgravity,” he said.

The significance of these experiments extends well beyond fundamental science. Colloidal clusters have been shown to scatter light in the visible to near-infrared spectrum, making them highly promising for applications in photonics, optical communications, and laser technologies. 

Their unique light-manipulating properties hint at future breakthroughs, including the potential development of advanced optical materials and even cloaking devices—innovations that capture the imagination much like the futuristic technologies portrayed in Star Trek.

Moreover, the ability to study these clusters in a space-based environment opens up new avenues for designing better materials. “

Read more on ANSTO website

BESSY II: Magnetic ‘microflowers’ enhance local magnetic fields

BESSY II: Magnetic ‘microflowers’ enhance local magnetic fields

A flower-shaped structure only a few micrometres in size made of a nickel-iron alloy can concentrate and locally enhance magnetic fields. The size of the effect can be controlled by varying the geometry and number of ‘petals’. This magnetic metamaterial developed by Dr Anna Palau’s group at the Institut de Ciencia de Materials de Barcelona (ICMAB) in collaboration with her partners of the CHIST-ERA MetaMagIC project, has now been studied at BESSY II in collaboration with Dr Sergio Valencia. Such a device can be used to increase the sensitivity of magnetic sensors, to reduce the energy required for creating local magnetic fields, but also, at the PEEM experimental station, to study samples under much higher magnetic fields than currently possible.

Dr Anna Palau from the Institut de Ciencia de Materials de Barcelona (ICMAB) has developed a special metamaterial that looks like tiny flowers under the scanning electron microscope. The ‘petals’ consist of strips of a ferromagnetic nickel-iron alloy. The microflowers can be produced in various geometries, not only with different inner and outer radii, but also with variable numbers and widths of petals. This flower-shaped geometry causes the field lines of an external magnetic field to concentrate in the centre of the device, resulting on a greatly intensified magnetic field.

Magnetic metamaterials

‘Metamaterials are artificially produced materials with microstructures whose dimensions are smaller than the electromagnetic or thermal waves they are designed to manipulate,’ explains Anna Palau. The physicist is working on magnetic microstructures that can be used in data storage, information processing, biomedicine, catalysis and magnetic sensor technology. By using these metamaterials, the sensitivity of magnetic sensors could be highly increased, as the magnetic field to be detected would be amplified at the center of these systems.

Read more on HZB website

Image: The magnetic microstructure of the nickel-iron alloy leads to a compression of the field lines in the centre.

Credit: A. Palau/ICMAB

A new 100 picosecond time-resolved technique images surface acoustic wave devices

A new 100 picosecond time-resolved technique images surface acoustic wave devices

Beamline ID01 can now study Surface Acoustic Waves (SAW) devices at operando conditions thanks to a new technique called stroboscopic full-field diffraction X-ray microscopy at the ESRF. Their results open the doors to more experiments with these systems and on electronic circuits and devices in general. They are published in Nature Communications.

A Surface Acoustic Wave (SAW) device is an electronic device that uses sound waves traveling along the surface of a material (usually a piezoelectric crystal) to process, filter or transmit signals. Their applications are wide, and include mobile phones, Wi-Fi, GPS, and 5G networks to filter and separate different frequency bands, touchscreens, sensors in the automotive and aviation industry, biosensors. They are also promising devices in nanoscale applications, such as quantum communication.

Because they are highly sensitive, durable, compact and cheap, there is a lot of ongoing research into understanding how to optimise their structure. This needs a deep understanding of energy conversion and loss mechanisms taking place in the device.

In SAW devices, electrical energy is converted into sound waves using interdigital transducers. These are tiny comb-shaped metal electrodes placed on a piezoelectric crystal. One set of electrodes is grounded, while the other receives an alternating voltage, causing the crystal’s surface to strain or deform. This vibration creates an acoustic wave that travels at several kilometers per second. These waves have extremely high frequencies (hundreds of MHz to GHz), far too fast for even the best high-speed cameras to capture.

However, now a team led by ESRF scientists has developed a technique called stroboscopic full-field diffraction x-ray microscopy on beamline ID01, which allows them to study the dynamic strain in SAW devices. “Today the spatial resolution at the ESRF’s ID01 is about 100nm and we have a time resolution in the storage ring of 100 picoseconds: this is practically the speed of sound . This means that we can image sound unblurred”, explains Tobias Schulli, scientist in charge of ID01 and co-corresponding author of the publication.

The experiments showed that there was an unexpected acoustic loss in a resonator device tested. It proved that propagating modes leak elastic energy away from the resonator. The high sensitivity of X-ray diffraction for changes in atomic distances by 1/100 000 together with the high time and spatial resolution available on ID01 represent the only available technique to detect and quantify such phenomena.

Read more on ESRF website

High-speed snapshots reveal hidden details of catalysis

High-speed snapshots reveal hidden details of catalysis

Developments in time-resolved catalysis research opens a long-awaited opportunity to revisit catalytic reactions that have been subject to scientific debate. In this recent publication, the newly developed method has been used to settle the mechanism for carbon monoxide transformation to carbon dioxide over a platinum catalyst. The result is an important step towards optimisation of catalysts.

The conversion of carbon monoxide to carbon dioxide with the help of a platinum catalyst is one of the most famous catalytic reactions and one that’s been studied for decades. It happens every day in every car catalytic converter to prevent the emission of highly toxic carbon monoxide. The mechanism for the reaction has, however, been subject to a lot of debate. 

It was a big success when, a few decades ago, carbon monoxide oxidation on platinum could be studied with a suite of surface science methods under idealistic conditions: ultrahigh vacuum and low temperatures. The studies suggested that oxygen bound to metallic platinum is the active species in the reaction. However, at the beginning of the 2000s, new tools and experimental methods that could probe the same reaction under realistic conditions, so-called operando, at elevated pressures and temperatures, started to appear. The results suggested a new candidate for the active species, platinum oxide, and the big debate started.

“The main challenge with such a materials system, however, is that although the oxide formation is indeed favourable under operando conditions, its presence does not imply reactivity. With studies done under equilibrium conditions, there is actually no way of telling,” says Andrey Shavorskiy, beamline scientist at the HIPPIE beamline and one of the authors of the study.

Dynamic and time-resolved surface studies have, with faster detectors and brighter synchrotrons, become a hot research topic. Ambient-Pressure X-ray Photoelectron Spectroscopy (AP-XPS) is a method that, through clever engineering, lets researchers do spectroscopic surface measurements under pressure conditions that otherwise would not be compatible with this type of study. It is especially important for catalysts where the function is closely connected to the operating pressure. Combining the two, time resolution with AP-XPS, at the HIPPIE beamline, shows promise for a new era of surface science studies.

“The main difference between all past studies and what we have done at HIPPIE was that we decided to follow the reaction as it happens in real-time. In collaboration with the Synchrotron Radiation Research Division of the Lund University Physics Department, we have developed a suite of time-resolved tools that allow us to look at chemical reactions on surfaces under operando conditions with high enough time resolution to detect the formation of intermediate species. The key parts of the development are the ability to initiate the reaction on the whole sample at the same time with a very fast valve that was developed at MAX IV and the ability to follow the response of the system under such a perturbation with a very high time resolution. We have pushed the AP-XPS experiment to its extreme and can obtain high-quality data with 20–40 µs time resolution. This has never been achieved before with chemical perturbations in an AP-XPS setup,” says Shavorskiy.

The researchers were able to follow the reaction closely and found the actual reaction mechanism, which, with a less exact method, could have been easily missed in overlapping signatures. They foresee that the method will be very attractive to their colleagues in the catalysis and surface science communities in the future.

“When we analyzed the collected spectra, we were able to identify a small region in time when the formation of oxygen bonded to metallic platinum was delayed with respect to the formation of platinum oxide. The reason for this, we reckon, is its very high activity. It never lives long enough on the surface to be detected as it is immediately consumed in the reaction. On the other hand, the platinum oxide is much less reactive, so it can stay on the surface unreacted, and we can detect it. 

Read more on MAX IV website

New material moves seawater batteries step closer to primetime

New material moves seawater batteries step closer to primetime

As the world makes more use of renewable energy sources, new battery technology is needed to store electricity for the times when the sun isn’t shining, and the wind isn’t blowing.

“Current lithium batteries have reached their limitations in terms of energy storage capability, life cycle, and safety,” says Xiaolei Wang, a professor of chemical engineering at the University of Alberta in Edmonton. “They’re good for applications like electric vehicles and portable electronics, but they’re not suitable for large-scale grid-level energy storage.”

With the help of the Canadian Light Source at the University of Saskatchewan, Wang and his team are developing new technologies to help make grid-level aqueous batteries that can use seawater as an electrolyte. Aqueous batteries can be safer, cheaper, and more environmentally friendly to make and dispose of than lithium-ion batteries, but their development has so far been limited by a lack of a good material to make a decent anode (the part of the battery where electricity flows out).

Wang’s team developed a material made of polymer nanosheets and carbon nanotubes that is suitable for storing a variety of different types of ions, including those found naturally in seawater. These anodes are thicker than previous ones, so have a high capacity for storing energy, and are extremely durable so they can last a long time – up to 380,000 charging cycles in some cases – and they can operate under extreme conditions such as fast charging and discharging, or at low temperatures, says Wang.

The ultrabright synchrotron light at the CLS was vital in understanding the microstructure of the anode material and its electrochemical behaviour. “The success of our project could not have been realised without CLS,” says Wang.

Read more on CLS website

Shaping the future of antibiotic design

Shaping the future of antibiotic design

Bacteria and fungi have been engaged in molecular warfare for millions of years. This means they have perfected ways to get past the defenses of other organisms and have also devised ways to keep them out. This arms race was revealed in 1928 when Alexander Fleming returned from his holidays to discover a petri dish of bacteria in which a fungus had started to grow and was killing the bacteria around it. He immediately realized the potential value of these antibiotic molecules to humans for curing disease. 

Now, however, our widespread use of natural antibiotics has led to the emergence of drug-resistant bacteria and an urgent need to develop some new molecular weapons of our own. With that in mind, a research group from the University of Michigan conducted a substrate-trapping study of bacterial enzymes that make an important class of antibiotics. The research provides important new information that will facilitate the design of new enzymes to make novel antibiotics that can overcome antibiotic resistance.

The group used the resources of the National Institute of General Medical Sciences and National Cancer Institute Structural Biology Facility (GM/CA) at beamlines 23-ID-B and 23-ID-D at the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science user facility at DOE’s Argonne National Laboratory.

The research focused on bacterial thioesterase (TE) enzymes that perform a critical step in a synthetic pathway to make macrolide antibiotics such as erythromycin and pikromycin. These TE enzymes temporarily attach antibiotic precursors to a nucleophilic amino acid in the TE, check the structural integrity of the precursor substrates, and then convert them to either a) a cyclic lactone molecule via nucleophilic attack by an oxygen atom in the substrate, or to b) a linear final product via attack by a water molecule. Although the structures of five TE enzymes that generate various products have been solved, the process by which a product is cyclized or hydrolyzed is poorly understood. 

To get a clearer picture of the final step in the antibiotic synthesis process that might help researchers to understand the parameters needed to make new antibiotics, the team decided to use a technique called substrate trapping to visualize the moment of decision between cyclization and hydrolysis in different TE enzymes. They used a new substrate trapping technique that incorporates a non-natural amino acid into the active site in place of the natural serine or cysteine nucleophile. The bond attaching a substrate to serine or cysteine is unstable, but the non-natural amino acid traps the reaction intermediate as a stable amide group (see Figure). 

After testing five bacterial TE enzymes to see if they could successfully incorporate the substrate trap, two of substrate trapping proteins could be purified in sufficient amounts for further testing, one that makes erythromycin and one that makes pikromycin, both cyclic antibiotics. 

Read more on APS website

Image: Model of the thioesterase enzyme active site with the cyclic substrate (purple) snugly fitted into the catalytic site of the TE (yellow). The substrate trap is represented by the blue nitrogen atom that forms a stable bond between the enzyme and substrate, preventing the substrate from leaving the site so the reaction intermediate can be studied at the molecular level. The substrate nucleophilic oxygen atom (red) is at the left end of the substrate.

Credit: Rajani Arora and Vishakha Choudhary of the University of Michigan.