Category: Chemistry

by Helmholtz Association of German Research Centres

A team from the Technical University of Berlin, HZB, IMTEK (University of Freiburg) and Siemens Energy has developed a highly efficient alkaline membrane electrolyzer that approaches the performance of established proton-exchange membrane(PEM) electrolyzers. What makes this achievement remarkable is the use of inexpensive nickel compounds for the anode catalyst, replacing costly and rare iridium.

At BESSY II, the team was able to elucidate the catalytic processes in detail using operando measurements, and a theory team (U.S., Singapore) provided a consistent molecular description. In Freiburg, prototype cells were built using a new coating process and tested in operation. The results have been published in the journal Nature Catalysis.

Hydrogen will play a major role in the energy system of the future, as an energy storage medium, a fuel and valuable raw material for the chemical industry. Hydrogen can be produced by electrolysis of water in a virtually climate-neutral way, provided this is done with electricity from solar or wind power.

Scale-up efforts for a green hydrogen economy are currently largely dominated by two systems: proton-conducting membrane electrolysis (PEM) and classic liquid alkaline electrolysis. AEM electrolyzers combine the advantages of both systems and, for example, do not require rare precious metals such as iridium.

Now, research teams from TU Berlin and HZB, together with the Department of Microsystems Engineering (IMTEK) at the University of Freiburg and Siemens Energy, have presented the first AEM electrolyzer that produces hydrogen almost as efficiently as a PEM electrolyzer. Instead of iridium, they used nickel double hydroxide compounds with iron, cobalt or manganese and developed a process to coat them directly onto an alkaline ion exchange membrane.

Insight into molecular processes during electrolysis at BESSY II

During the electrolysis in the cell, they were able to carry out operando measurements at the Berlin X-ray source BESSY II at the LiXEdrom end station. A theory team from Singapore and the U.S. helped to interpret the experimental data.

“This enabled us to elucidate the relevant catalytic-chemical processes at the catalyst-coated membrane, in particular the phase transition from a catalytically inactive alpha phase to a highly active gamma phase and the role of the various O ligands and Ni⁴⁺ centers in the catalysis,” explains Prof. Peter Strasser, TU Berlin.

“It is this gamma phase that makes our catalyst competitive with the current state-of-the-art iridium catalysts. Our work shows important similarities to iridium in the catalytic mechanism, but also some surprising molecular differences.”

The study has thus significantly advanced our understanding of the fundamental catalysis mechanisms of the new nickel-based electrode materials. In addition, the newly developed coating method for the membrane electrode promises excellent scalability. A first fully functional laboratory cell has already been tested at IMTEK. The work lays the foundation for further industrial evaluation and demonstrates that an AEM water electrolyzer can also be highly efficient.

More information: M. Klingenhof et al, High-performance anion-exchange membrane water electrolysers using NiX (X = Fe,Co,Mn) catalyst-coated membranes with redox-active Ni–O ligands, Nature Catalysis (2024). DOI: 10.1038/s41929-024-01238-w

Journal information: Nature Catalysis 

by Duke University

Additive manufacturing (AM) has revolutionized many industries and holds the promise to affect many more in the not too distant future. While people are most familiar with the 3D printers that function much like inkjet printers, another type of AM offers advantages using a different approach: building objects with light one layer at a time.

One such technology is digital light processing (DLP). Widely used in both industrial and dental applications, DLP works by converting a liquid resin into a solid part using light, essentially pulling solid objects out of a shallow pool of resin one layer at a time.

A major challenge to using this 3D printing method, however, is that the resins need to have a low viscosity, almost like water, to function properly at high resolution. Plenty of polymers that would otherwise be useful in DLP printing are solids or too viscous, requiring solvents to dilute them to an appropriate consistency.

But adding these solvents also causes significant drawbacks, like poor dimensional accuracy after printing due to part shrinkage (up to 30%) coupled with residual stress that occurs as the solvent evaporates.

In a paper published in Angewandte Chemie International Edition, researchers at Duke University have invented a new solvent free polymer for DLP printing. Besides eliminating the shrinkage problem, the lack of solvent also results in improved mechanical properties of the part while maintaining the ability to degrade in the body.

“I wanted to create an inherently thin, low-viscosity material for DLP to use for degradable medical devices,” said Maddiy Segal, a MEMS Ph.D. candidate working in the laboratory of Matthew Becker, the Hugo L. Blomquist Distinguished Professor of Chemistry at Duke. “It took a lot of attempts, but eventually I was able to identify optimal monomers and a synthetic technique to create a solvent free polymer that can be used in a DLP printer without any dilution.”

Since the new material is one of the first solvent free resins that can be used in DLP printing, Segal was interested in testing the properties of parts made with it. She was excited to discover that the test parts did not shrink or distort at all, and in general, they were also stronger and more durable than those made with solvents. According to her findings, this is one of the first empirical demonstrations of increased mechanical properties from eliminating solvent use in DLP 3D printing of degradable polymers.

To create her new polymer, Segal analyzed the structure and properties of existing resins developed by the Becker Lab and others and modified the monomers and chain length in a step-by-step empirical approach to achieve the desired low-viscosity polymers. She essentially used a “guess and check” approach, adjusting the polymer’s monomers or “recipes” until she found a combination that worked.

The process isn’t entirely dissimilar from cooking a meal. It involves mixing specific combinations of ingredients, heating them, and then testing the results until achieving the desired outcome. In total, Segal experimented with about 60 different combinations before finally making the product she had been hoping for.

“Besides making a material that didn’t shrink and was stronger, I also wanted it to be useful for medical applications,” Segal said. “I’m trying to make prototype devices that are both biocompatible and degradable. Eliminating toxic solvents from the process will help me do that.”

Segal’s ultimate goal with this work is to apply this technique to biodegradable medical implants. Some materials used to make temporary medical implants today are not degradable and require multiple surgeries to not only implant them, but also remove them. Through her research, Segal aims to develop implants that can be degraded through the body’s natural processes.

Devices fabricated from this material could be implanted and designed to degrade naturally over time, eliminating the need for additional surgeries to remove the device. It could also potentially be used as a bone adhesive to hold fractures together temporarily or in soft robotics applications, where a soft, degradable material is needed.

“This kind of material is what makes this particular application the primary goal of my work,” Segal said. “And in reality, this technique could be used for any sort of implant that you would want to degrade after some time and not stay there forever.”

More information: Maddison I. Segal et al, Synthesis and Solvent Free DLP 3D Printing of Degradable Poly(Allyl Glycidyl Ether Succinate), Angewandte Chemie International Edition (2024). DOI: 10.1002/anie.202414016

Journal information: Angewandte Chemie International Edition 

by Pennsylvania State University

A newly discovered protein naturally houses an unusual binding site that can differentiate between rare earth elements, and researchers at Penn State have made it even better. Rare earth elements are key components used in everything from modern tech to gasoline production. The protein, called LanD, enriches neodymium and praseodymium over other similar rare earth elements (REEs) and has the potential to revolutionize industrial mining, researchers said.

Scientists at Penn State, led by professor of chemistry Joseph Cotruvo, Jr., recently published their LanD discovery in the Proceedings of the National Academy of Sciences.

“Each rare earth element has specific properties that make it useful for different applications, yet they are notoriously difficult to separate from each other,” said Cotruvo, who has filed a patent application related to the work. “Current industrial methods are inefficient and require heavy use of toxic chemicals, so a protein-based method for rare earth mining could make this process more efficient, greener, and less expensive.”

Close to 80% of the United States’ REE supply is imported, according to the United States International Trade Commission. Cotruvo explained that there is plenty of domestic raw material—including recycling old tech and industrial byproducts—to source REEs, but not all REEs are of equal value and application.

A more effective separation approach could help secure a national supply of REEs. The 17 REEs, including 15 metals called “lanthanides,” are commonly divided into “light” and “heavy” groups, with the light REEs being far more abundant. Unfortunately, however, the most common light REEs, lanthanum and cerium, have little value, whereas the other light REEs, praseodymium and (in particular) neodymium, are much more valuable.

Neodymium is a critical component of permanent magnets used in smartphones and renewable energy machinery like wind turbines, and praseodymium is often combined with neodymium for these applications.

Cotruvo’s lab previously identified another protein, LanM, that binds to all REEs with high specificity over any other metal. It does this in a fashion similar to a lock and key mechanism, with the protein being the lock and the REE a key. When the protein binds a REE, it undergoes a change in shape analogous to the key turning in the lock. The LanM proteins studied to date are very good at differentiating between heavy REEs, but they do not do well separating the light REEs, akin to a keyhole that fits a few different keys.

The newly discovered LanD protein, however, has improved separation abilities among the light REEs that are as good as, if not better than, current industry practices, Cotruvo said. With a unique, never-before-seen binding site—where the metal “key” can lock into the protein—LanD’s natural REE separation abilities can be engineered to be even more efficient, offering new hope for a greener rare earth element mining industry, he said.

“Current efforts are concentrated towards optimizing REE separation to make it less labor and material intensive,” Cotruvo said. “But this organism, Methylobacterium extorquens, a bacterium found abundantly in nature, makes proteins that seem to have already solved the problem.”

Methylobacterium extorquens is a species of bacteria known for its ability to grow on one-carbon compounds like methanol, and prefers to use specific REEs, mostly lanthanum and cerium, to support that growth.

When Cotruvo discovered LanM as the first high-affinity, high-specificity REE-binding protein six years ago, it was not clear why LanM needed to bind REEs so tightly in the cell. The discovery of LanD suggested an answer to that question: the two proteins work in tandem, with LanD binding to the lanthanides that the bacterium takes up but doesn’t need and delivering them to LanM, where they are sequestered. Those lanthanides, while not important to the bacteria, are the ones that are most important to tech production, Cotruvo said.

“The bacterium can take up a broader group of lanthanides than the small subset that it prefers to use, so it needs a way to prevent those undesirable lanthanides from interfering with the functions of the desirable lanthanides in the cell,” Cotruvo said. “LanD and LanM appear to work together to do this sorting, which explains why the previously identified LanM protein is good at lanthanide separations in general.”

He added that LanD, with its unique binding site, is much better for the light REEs specifically.

“LanD conveniently binds best to neodymium, which is by far the most valuable of the light REEs,” Cotruvo said. “While the naturally occurring LanD protein exhibits a preference for neodymium, we re-engineered it to more effectively be able to extract neodymium from a mixed solution of light REEs, disfavoring the other REEs that are of lesser value.”

The researchers found that engineering the LanD binding site allows separations yielding the desired neodymium and praseodymium to become much more effective. In future applications, the researchers said they hope to be able to whittle down the protein size and increase the preference of this binding site even more—and implement it in a larger-scale separation. The site can serve as the starting point for chemists and engineers to develop highly specific proteins to perfect sorting of other tricky-to-separate elements, Cotruvo said.

Furthermore, because LanD and LanM specialize in separation of different REEs, they could be used together in a process to separate complex REE sources like ores.

“The LanD protein is a promising way to improve REE separation practices,” he said. “And we’re working on making it even better, to pave a path toward more effective, greener rare earth mining.”

Paper co-authors include Wyatt Larrinaga and Jonathan Jung, graduate students in chemistry; Chi-Yun Lin, postdoctoral researcher in chemistry; and Amie Boal, professor of chemistry and of biochemistry and molecular biology.

More information: Wyatt B. Larrinaga et al, Modulating metal-centered dimerization of a lanthanide chaperone protein for separation of light lanthanides, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2410926121

Journal information: Proceedings of the National Academy of Sciences 

Provided by Pennsylvania State University 

by Food Packaging Forum Foundation

Plastics contain a vast number of chemicals, some of which greatly impact the environment and human health. However, information on the presence of individual substances in plastic products is oftentimes not publicly available.

In a study, published on 29 October 2024, in Environmental Science and Technology Letters, a new publicly accessible database on chemicals measured in plastics is presented—LitChemPlast. The database contains over 3,500 substances measured in over 47,000 samples of plastic products across 372 studies.

The database shows that, due to inadequate control measures, mechanical recycling of plastics often leads to contamination with hazardous substances. For example, brominated flame retardants have frequently been detected in toys.

LitChemPlast is a significant step forward for better understanding of chemicals’ movement through different life stages of plastics. The database provides real-world chemical data, including on concentrations in products, that is useful for improving models estimating human and environmental exposure to plastic chemicals.

Moreover, LitChemPlast enables researchers, regulators and practitioners to identify chemicals that are of interest for regulation, to find safer materials for recycling, and to trace plastic pollution back to its source. It may also assist in identifying hazardous chemicals that are non-intentionally added to plastics (so called NIAS).

LitChemPlast also highlights research gaps, such as limited regional coverage in low- and middle-income countries, a lack of nontargeted measurements for non-food packaging categories, and a narrow focus on well-known hazardous chemicals.

Future concerted efforts in these understudied areas are essential to support the transition toward a safe and sustainable circular plastics economy, including achieving full transparency of chemicals in plastics.

The open database can serve as a starting point for guiding future research on identifying and quantifying chemicals in plastics, develop policy measures for ensuring safer material cycles, and support researchers, regulators and practitioners in better understanding the flow of chemicals throughout plastic products’ life cycles.

Finally, the authors encourage the scientific and regulatory communities to continue developing and using the database which is part of the larger PlastChem database that was published earlier in 2024.

Helene Wiesinger, Ph.D., currently scientific officer at the Food Packaging Forum and corresponding author of the study said, “Many scientific efforts focus only on whether plastics comply with current regulations, rather than whether they are actually safe. This is worrying because there are many chemicals in plastics that are not yet adequately regulated, meaning that potential risks could slip through the cracks.”

Zhanyun Wang, Ph.D., Scientist at Empa—Swiss Federal Laboratories for Materials Science and Technology and corresponding author of the study said, “Transparency of chemicals in plastics is crucial for ensuring safer material cycles, protecting human and environmental health, and fostering a sustainable circular economy.

“LitChemPlast marks a significant step in this direction, and we encourage widespread collaboration to further expand and refine this valuable resource.”

More information: LitChemPlast: An open database of chemicals measured in plastics, Environmental Science & Technology Letters (2024). DOI: 10.1021/acs.estlett.4c00355

Journal information: Environmental Science & Technology Letters 

by Meike Drießen, Ruhr-Universitaet-Bochum

Using state-of-the-art microscopy and simulation techniques, an international research team has systematically observed how iron atoms alter the structure of grain boundaries in titanium. Their findings were published in the journal Science on October 25, 2024.

They were in for a surprise: “Iron atoms not only segregate to the interface, but they form entirely unexpected cage-like structures,” explains Prof. Dr. Christian Liebscher from the Research Center Future Energy Materials and Systems of the University Alliance Ruhr. The researchers did not expect such a behavior.

A new type of segregation behavior

Most technological materials have a polycrystalline structure: They are composed of different crystals, where atoms are arranged in a regular lattice. These crystals do not have the same orientation everywhere and the interfaces separating them are known as grain boundaries.

“These grain boundaries have an enormous influence on the durability and overall performance of a material,” says Dr. Vivek Devulapalli, who performed the microscopy work in the study. “But we have very limited understanding of what happens when elements segregate to grain boundaries and how they influence the properties of a material.”

The key to success was to observe and model the structures at atomic resolution. The researchers correlated their results from atomic-resolution scanning transmission electron microscopy with advanced computer simulations. A new grain boundary structure prediction algorithm was able to generate the experimentally observed structures and enabled study of their structure.

“Our simulations show that for different iron contents, we always find the cage structures as the underlying building blocks of different grain boundary phases. As the iron level increases at the grain boundary, more icosahedral units appear and eventually agglomerate,” explains Dr. Enze Chen from Stanford University. An icosahedron is a geometric object with 12 corners or vertices, in this case occupied by atoms, and 20 planes.

“We have identified more than five distinct structures or grain boundary phases of the same boundary, all composed of different arrangements of the same icosahedral cage units,” adds Dr. Timofey Frolov, who led the computational work of the study.

Quasicrystalline-like grain boundary phases

A closer inspection of the cage structures revealed that the atoms adopt an icosahedral arrangement with iron atoms being located at the center of the icosahedron and titanium atoms occupying its vertices. “The icosahedral cages enable a dense packing of iron atoms and since they can form aperiodic clusters, more than two to three times the amount of iron can be accommodated at the grain boundary,” explains Devulapalli.

“It appears as if iron is trapped inside of quasicrystalline-like grain boundary phases,” adds Chen.

“This is attributed to the properties of the icosahedral cages,” says Liebscher, “and we now need to find ways to study how they influence the interface properties and this material behavior.”

New pathways for materials design

Understanding and controlling the formation of icosahedral grain boundary phases with different structures and properties can potentially be used to tailor the properties of materials.

The researchers now want to systematically investigate how these novel grain boundary states can be used to tune material behavior, adjust a certain material functionality and to make materials more resilient against degradation processes.

More information: Vivek Devulapalli et al, Topological grain boundary segregation transitions, Science (2024). DOI: 10.1126/science.adq4147

Journal information: Science 

Provided by Ruhr-Universitaet-Bochum 

by University of Sheffield

Researchers have made a significant breakthrough in understanding how certain pathogens defend themselves against the host’s immune system.

This collaborative study, led by scientists from the University of Sheffield, as well as other British, Dutch and Chinese institutions focuses on the role of a group of enzymes known as zinc-dependent macrodomains (Zn-Macros) in reversing ADP-ribosylation, a vital cellular process.

This discovery could lead to innovative treatments to combat antimicrobial resistance, a growing global health threat. The work is published in the Journal of Biological Chemistry.

ADP-ribosylation is a reversible modification of proteins and DNA that regulates important cellular responses to stress. While this signaling mechanism is well-studied in higher eukaryotes, where it regulates responses to DNA damage, reactive oxygen species and infection, the importance of its role in microorganisms is also becoming increasingly evident, which includes the regulation of the host immune response, microbial immune evasion and adaptation to specific hosts.

The research team used a combination of phylogenetic, biochemical, and structural approaches to investigate the function of Zn-Macros. These enzymes are found in some pathogenic microbes and are essential for removing ADP-ribosyl modifications, thereby helping the pathogens survive oxidative stress.

The study revealed that the catalytic activity of Zn-Macros is strictly dependent on a zinc ion within the active site of these enzymes. The researchers also identified structural features that contribute to substrate selectivity within different types of Zn-Macro enzymes, which may be exploited for the development of future therapies.

The findings have significant implications for the fight against bacterial and fungal infections that pose an increasing risk to human health, a problem that is exacerbated by the development of antimicrobial resistance and the emergence of multidrug-resistant strains. The World Health Organization has published lists of priority pathogens that pose the greatest risk, emphasizing the need for new antimicrobial strategies.

Addressing antimicrobial resistance will require a multifaceted strategy, including the discovery and characterization of new antimicrobial targets, along with assessing their potential for therapeutic use in innovative (co-)treatment approaches.

The authors of the study suggest that targeting the Zn-Macro pathway could reduce the virulence of major human pathogens, including Staphylococcus aureus and Streptococcus pyogenes. These pathogens rely on the crosstalk between lipoic acid metabolism and ADP-ribosylation signaling for their defense mechanisms. Disrupting this pathway could enhance the effectiveness of existing treatments and provide new therapeutic options.

The study’s findings represent a significant step forward in the fight against antimicrobial resistance and highlight the potential of Zn-Macros as therapeutic targets.

“Our findings uncover the evolutionary and molecular mechanisms behind ADP-ribosylation reversal by zinc-dependent macrodomains. By understanding this regulatory process, we can explore new avenues for drug development in diseases where ADP-ribosylation plays a critical role.

“I believe that further investigation into the physiological role of Zn-Macros could lead to the development of new antimicrobial therapies as these enzymes are primarily found in pathogenic microorganisms and have structurally distinct features that make them suitable for drug development,” says Dr. Antonio Ariza, university teaching associate.

More information: Antonio Ariza et al, Evolutionary and molecular basis of ADP-ribosylation reversal by zinc-dependent macrodomains, Journal of Biological Chemistry (2024). DOI: 10.1016/j.jbc.2024.107770

Journal information: Journal of Biological Chemistry 

by American Chemical Society

Today, people increasingly seek non-alcoholic versions of beer or wine. Despite boasting different flavors, these two drinks share many aromas, which makes it difficult to produce alcohol-free versions that mimic the real thing. Researchers in the Journal of Agricultural and Food Chemistry report on a literature analysis and experiment to characterize the chemical compounds that give beer and wine their unique fragrances. They say their findings could aid the development of flavorful, non-alcoholic substitutes.

Food and beverage researchers are working to recreate the enjoyable aromas and flavors of beer and wine in alcohol-free substitutes. However, because both beer and wine are fermented, they have similar fragrances, and little is known about which scents evoke the unique character of each drink. So, Xingije Wang, Stephanie Frank and Martin Steinhaus set out to identify the key ingredients that distinguish the aroma of beer from that of wine.

First, the team conducted a literature review and identified the average proportions of 29 compounds from beer and 32 from wine that make up the drinks’ aromas. The researchers used these proportions like recipes to concoct standard beverages that smelled like either beer or wine.

From there, they tweaked these standards, swapping levels of select fragrances in the beer-like beverage to match those in the wine-like beverage, or vice versa, to test which ingredients influenced the perception of each drink. Trained taste-testers smelled each tweaked sample and evaluated it on a scale of beer-like to wine-like.

The researchers report that the taste-testers found that stronger fruity aromas made drinks smell more like wine. The team also swapped the entire profile of scented compounds from one standard into the opposite drink’s base liquid. They discovered that the scented compounds, rather than the base liquid, made the biggest difference in beer- versus wine-like aroma to the testers. The researchers say their results could be used to develop drinks that better mimic beer or wine while meeting consumers’ preferences for non-alcoholic options.

More information: Xingjie Wang et al, Molecular Insights into the Aroma Difference between Beer and Wine: A Meta-Analysis-Based Sensory Study Using Concentration Leveling Tests, Journal of Agricultural and Food Chemistry (2024). DOI: 10.1021/acs.jafc.4c06838

Journal information: Journal of Agricultural and Food Chemistry 

by Macquarie University

A new review of the research on cell-penetrating peptide (CPP) clusters by scientists from Macquarie University and Oxford University will provide a roadmap for biomedical scientists to develop the next generation of treatments for cancer and neurodegenerative diseases.

Biological barriers such as the blood-brain barrier and the plasma membrane, which protects neurons, prevent toxins from attacking the central nervous system, but they also stop potentially lifesaving treatments from reaching their intracellular targets.

More than half of the structures in the body that could potentially be affected by medicines are found inside the cells, making it vital to find ways of carrying large molecules like antibodies and genetic treatments across these biological barriers.

CPPs were first discovered three decades ago as a potential answer to the problem. They are cheap to produce, have a long history in research, and are easy to integrate into biologic drugs, but issues with their efficacy have meant that no therapies using them have yet been approved by the world’s regulatory bodies.

A breakthrough came two years ago, in the form of CPP clusters that could be created to carry cargos of antibodies, proteins, enzymes, and peptides across biological barriers.

Oxford University researchers created the first tricyclic CPP cluster, which was also the first in the world to transport functional antibodies into cells at low concentrations. At the same time, another research team from Nanyang Technological University in Singapore made a conceptually similar discovery, using a different agent to transport mRNA into cells.

Dr. Ole Tietz, one of the Oxford team, is now a Senior Research Fellow at the Macquarie University Dementia Research Centre (DRC). He says this breakthrough marked a fundamental shift in the understanding of how CPPs could be used.

“The key to successful CPP cluster carriers lies in arranging them in a specific configuration, so they can act as a key to the barrier’s lock,” he says. “These clusters are molecular Trojan horses, fooling the blood-brain barrier into allowing the molecules they’re carrying to cross over.

“Until now, many therapies have had to be administered in very high doses for a small amount to get through, and this can cause cytotoxicity, which can have very serious effects. There is a small therapeutic window with these treatments, after which you reach a concentration that is toxic and starts killing the cells instead.

“These new generation CPPs have the potential to allow us to deliver the minimum needed for treatment, which could improve patient outcomes dramatically.”

To help other biomedical scientists navigate the development and use of CPPs, Dr. Tietz’s team has written a systematic review, published in the latest edition of Trends in Chemistry, that collects all the research findings on this new class of CPP, effectively creating a roadmap to using the new paradigm.

Lead author, Joseph Reeman, a Master of Research student at Macquarie Medical School, says one of the key aspects of the paper is its provision of a set of design criteria.

“These guidelines will assist researchers in developing the next generation of intracellular therapeutics, with a focus on translation into clinical practice,” he says.

“We cover how to use existing CPP clusters with cargos and how to create new clusters, the outstanding questions of what needs to happen in the field, as well as some of what we are currently addressing through our research program.”

The team is currently developing a CPP cluster that they hope could be used as a “plug and play” carrier for various types of intracellular treatments, including antibodies and gene therapies. Animal testing has already shown it can penetrate the brain, and they are now investigating whether it can transport an antibody across the blood-brain barrier and into a neuron.

If successful, it could be used to target the pathogenic build-ups of the brain proteins TDP-43 and tau that are associated with neurodegenerative diseases including Alzheimer’s disease, frontotemporal dementia and motor neuron disease, which are a key research focus for DRC scientists.

More information: Joseph Reeman et al, Strength in numbers: cell penetrating peptide clusters to build next-generation therapeutics, Trends in Chemistry (2024). DOI: 10.1016/j.trechm.2024.09.003

Journal information: Trends in Chemistry 

Provided by Macquarie University 

by Jessica Marsh, University of Manchester

Scientists have developed a new material capable of capturing the harmful chemical benzene from the polluted air, offering a potential solution for tackling a major health and environmental risk.

The study, led by scientists at The University of Manchester, has revealed that a material known as a metal-organic framework (MOF)—an ultra-porous material—can be modified to capture and filter out significantly more benzene from the atmosphere than current materials in use.

Benzene is primarily used as an industrial solvent and in the production of various chemicals, plastics, and synthetic fibers, but can also be released into the atmosphere through petrol stations, exhaust fumes and cigarette smoke. Despite its widespread applications, benzene is classified as a human carcinogen, and exposure can lead to serious health effects, making careful management and regulation essential.

The research, published in the journal Nature Materials today, could lead to significant improvements in air quality both indoors and outdoors.

“The removal of benzene at low concentrations has been a long-standing challenge, especially in real-world conditions. Current methods such as oxidation or biological treatment often struggle with efficiency and can produce hazardous by-products. This research tackles both of those problems and is an important step forward in addressing one of the most ubiquitous health and environmental challenges,” says senior researcher Martin Schröder, Professor of Chemistry at The University of Manchester.

MOFs are advanced materials that combine metal centers and organic molecules to create porous structures. They have a highly adjustable internal structure, making them particularly promising for filtering out harmful gases from the air.

The researchers modified the MOF structure—known as MIL-125—by incorporating single atoms from different elements, including zinc, iron, cobalt, nickel and copper to test which would most effectively capture benzene.

They discovered that adding a single zinc atom to the structure significantly enhanced the material’s efficiency, enabling it to capture benzene even at ultra-low concentrations—measured at parts per million (ppm)—a significant improvement over current materials.

The new material—now known as MIL-125-Zn—demonstrates a benzene uptake of 7.63 mmol per gram of material, which is significantly higher than previously reported materials.

It is also highly stable even when exposed to moisture, maintaining its ability to filter benzene for long periods without losing effectiveness. Tests show that it can continue removing benzene from air even under humid conditions.

“This breakthrough illustrates the power of atomic-level modifications in materials science. While our current research focuses on benzene, our design and methodology opens the door to adaptation to capture a wide range of air pollutants. The research provides a new approach for studying how these materials interact with gases, helping to develop more effective solutions for environmental and industrial challenges,” says co-lead researcher Sihai Yang, Professor of Chemistry at The University of Manchester.

As the research progresses, the team will look to collaborate with industry partners to develop this and related new materials, with the potential of integrating them into ready-made devices, such as air purification systems in homes, workplaces, and industrial settings.

More information: Yu Han et al, Trace benzene capture by decoration of structural defects in metal–organic framework materials, Nature Materials (2024). DOI: 10.1038/s41563-024-02029-1

Journal information: Nature Materials 

by Osaka University

Achieving a sustainable society requires the development of advanced degradable plastics, or polymers, which are molecules composed of long chains of repeating units. The goal of a resource-circulating society is now one step closer thanks to the efforts of a team from Osaka University that has developed tough biodegradable plastics by including movable crosslinking groups.

In a study published this month in Chem, the researchers have revealed that developing polymers with movable crosslinks not only increases their strength but also promotes degradation by enzymes under mild conditions.

Plastics and polymers need to achieve both desirable performance in terms of durability and strength, as well as triggerable degradation capability to enable their breakdown into useful components for reuse. At present, there is a tradeoff between these factors; i.e., increased toughness makes the polymer more difficult to degrade. The researchers have used movable crosslinks to resolve this problem.

The movable crosslinks are ring-like cyclodextrins, which are threaded on one polymer strand and attached to another, endowing the resulting plastics with increased toughness and durability. Cyclodextrins are nontoxic, biodegradable, and widely available, making them attractive as a polymer component.

“Our polymer design using movable cyclodextrin crosslinks increased polymer toughness by over eight times,” says lead author of the study Jiaxiong Liu. “Stiffness, ductility, fracture stress, and fracture strain all improved because the cyclodextrin groups effectively dispersed local stress.”

The cyclodextrin crosslinks also facilitated degradation of the polymers during subsequent enzymatic treatment because their bulky structure increased the free volume in the polymer network, which improved access of the enzyme to the target cleavage sites on the polymer chains.

“The polymers were readily degraded by Novozym 435, an enzyme that specifically attacks the ester bonds of the polymer backbone,” explains Yoshinori Takashima, senior author. “The presence of the bulky cyclodextrin crosslink groups decreased entanglement and aggregation of the polymer chains, which facilitated the access of the enzyme to the ester bonds for cleavage.” As a result, biodegradability was improved by twenty times compared with that of the polymer without cyclodextrin groups.

These advanced biodegradable plastics can readily be broken down by enzymes into useful precursor molecules that could be reused in further materials, suppressing waste generation and contributing to the development of a sustainable society.

More information: Exploring Enzymatic Degradation, Reinforcement, Recycling and Upcycling of Poly(ester)s-Poly(urethane) with Movable Crosslinks, Chem (2024). DOI: 10.1016/j.chempr.2024.09.026. www.cell.com/chem/fulltext/S2451-9294(24)00494-7

Journal information: Chem