Could the future of data storage be DNA? It’s the original format after all, storing the information needed to build every living thing.
And it has a handful of qualities that would make it perfect for storing all the digital information in our world.
With recent advances in sequencing and printing DNA, it’s technically possible, but there are a few obstacles to overcome before this sci-fi-sounding tech can become a household reality.
Provided by American Chemical Society
Polymers are lightweight, durable, and easily processed into fabricated parts, features that promoted polymers to become the most relevant class of engineering materials by volume. However, recycling polymers is a challenge that materials scientists have been researching for decades.
An alternate route toward a more sustainable polymer industry is to increase the service lifetime of polymers. An intriguing new concept is to impart the ability to “self-heal” from structural damage. Michael Bockstaller, professor of materials science and engineering at Carnegie Mellon University Materials Science and Engineering, in collaboration with Krzysztof Matyjaszewski, professor of chemistry, has discovered that the binding of copolymers on the surface of nanoparticles that are already used in industrial manufacturing provides an economic and scalable route toward self-healing polymers with increased strength and toughness.
Normally when you think of the building blocks of materials, you think of atoms. In Bockstaller’s research group, this concept inspired a new approach to fabricate functional materials by assembling nanoparticle building blocks using a form of atom transfer radical polymerization, a technique invented and developed by Matyjaszewski. The properties of the resulting materials can be varied by controlling the interactions between nanoparticle building blocks. This concept opens up new possibilities to vary properties of engineering materials without having to change their chemical composition—a feature that is highly beneficial in the context of recyclability.
While working to make these particles more amenable to fabrication technologies like additive manufacturing, Bockstaller’s team experimented with putting copolymers at the surface of nanoparticles.
“If we can put polymers on the surface of nanoparticles, we can improve the interactions between them and make materials more mechanically robust and easier to form,” Bockstaller said.
Matyjaszewski added, “This work illustrates how controlling macromolecular architecture can dramatically enhance properties of various advanced materials.”
Copolymers are a special class of polymers that are made up of two different monomers and exhibit self-healing properties. The researchers found that when copolymers were added onto the surface of nanoparticles, new structures were formed that enhanced the polymer’s self-healing properties. This discovery is foundational to improving the recyclability of polymers.
“This enables us to avoid material failure,” Bockstaller explained. “If the material can self-heal, we reduce the need to discard materials damaged by stress.”
Bockstaller’s group will continue to explore strategies to maximize strength and toughness of copolymer-based self-healing materials and to make them available to scalable production methods.
This research was published in Macromolecules.
More information: Yuqi Zhao et al, Topologically Induced Heterogeneity in Gradient Copolymer Brush Particle Materials, Macromolecules (2022). DOI: 10.1021/acs.macromol.2c01131
Provided by Carnegie Mellon University Materials Science and Engineering
Dr. Emily Pentzer, associate professor in the Department of Materials Science and Engineering and the Department of Chemistry at Texas A&M University, is making 3D-printed polymers more environmentally friendly through a process that allows the polymers to naturally degrade over time. Pentzer’s research is a collaborative effort that includes researchers from the Texas A&M College of Engineering, the Texas A&M Engineering Experiment Station, the Texas A&M Department of Chemistry and the University of Kashmir.
The research was published in the journal Angewandte Chemie.
“Our goal was to create sustainable degradable polymeric structures,” Pentzer said. “We did this by leveraging the microstructures afforded by chemistry in conjunction with the macrostructures afforded by 3D printing.”
Most commercial synthetic polymers consist of large molecules that do not break apart under normal conditions. When left in the environment, manufactured items such as Styrofoam cups or plastic containers break down into small pieces that are unseen by the naked eye, but the long polymer molecules remain present forever.
“It’s not just the plastic bottle being kicked down the road,” Pentzer said. “These materials break down into microplastics that stay in the environment. We don’t fully understand the impact of microplastics, but they’ve been shown to carry diseases, heavy metals and fecal bacteria.”
To make the degradable polymers Pentzer collaborated with Dr. Don Darensbourg, distinguished professor in the Department of Chemistry at Texas A&M, to use carbon dioxide and table salt to create the ink that was used in the 3D printing process. After printing, the structures are washed with water to dissolve the salt and solidify the structure. While the outside of the structure continues to look smooth, the process creates thousands of small pores which allow the chemical compounds to degrade at a quicker rate.
“Under the right conditions, the polymers we’ve created will actually degrade quickly,” Pentzer said. “Ideally, they’ll break apart into small molecules that are not toxic. These smaller molecules won’t be able to carry things like heavy metals or bacteria.”
As the research progresses, Pentzer hopes to use this process to create packaging materials so that things like boxes and tape can degrade quickly rather than sitting in a landfill for years to come. She also sees a bright future for 3D-printed polymers in the biomedical field.
“These materials can be used for diverse biomedical applications,” Pentzer said. “Things like scaffolds for implants that will degrade over time so your body can heal, but you won’t have that piece of plastic in you forever.”
Through her interdisciplinary research, Pentzer is seeking to solve a worldwide problem that could have implications on the environment, human health, biomedicine and almost every aspect of human existence.
“It’s kind of like marrying the science with the engineering,” Pentzer said. “Working together, we can create synergy and achieve much more.”
More information: Peiran Wei et al, 3D Printed CO 2 ‐Based Triblock Copolymers and Post‐Printing Modification, Angewandte Chemie International Edition (2022). DOI: 10.1002/anie.202208355
Journal information: Angewandte Chemie International Edition , Angewandte Chemie
Provided by Texas A&M University College of Engineering
When you cut yourself, a mass migration begins inside your body: Skin cells flood by the thousands toward the site of the wound, where they will soon lay down fresh layers of protective tissue.
In a new study, researchers from the University of Colorado Boulder have taken an important step toward unraveling the drivers behind this collective behavior. The team has developed an equation learning technique that might one day help scientists grasp how the body rebuilds skin, and could potentially inspire new therapies to accelerate wound healing.
“Learning the rules for how individual cells respond to the proximity and relative motion of other cells is critical to understanding why cells migrate into a wound,” said David Bortz, professor of applied mathematics at CU Boulder and senior author of the new study.
The research is the latest in a decade-long collaboration between Bortz and Xuedong Liu, professor of biochemistry at CU Boulder. The group’s method, called the Weak form Sparse Identification of Nonlinear Dynamics (WSINDy), can apply to a wide range of phenomena in the natural world, said study lead author Dan Messenger.
“While this paper is about cells, the math is also applicable to a wide range of fields, including how flocks of birds avoid both predators and each other,” said Messenger, a postdoctoral researcher in Bortz’s lab.
He and his colleagues published their results Oct. 12 in the Journal of The Royal Society Interface.
The research hinges on a set of tools from the field of “data-driven modeling,” an emerging area at the intersection of applied math, statistics and data science. Using this approach, the group designed computer simulations of hundreds of cells moving toward an artificial wound, then built a method to learn the equations to describe and examine the motion of each individual cell. The team’s tools are potentially much faster and more accurate than traditional modeling approaches—a boon for understanding complex natural phenomena like wound healing.
“To prevent infections, we want our wounds to close as soon as possible,” Liu said. “We plan to use these learned models to test pharmaceuticals and drug regimens that might be able to stimulate wound healing.”
Trial and error
Mathematical models come in a lot of shapes and sizes, but most use a complex series of equations to try to capture some phenomenon in the real world.
Bortz, for example, joined a team of scientists in 2020 who drew on models to try to predict the spread of COVID-19 in Colorado. But, he noted, it can take a lot of trial and error, and even supercomputers, to validate those equations.
“Developing an accurate and reliable model can be a very long and laborious process,” Bortz said.
In this new study, he and his colleagues extended their recently-developed WSINDy method to directly use data to learn models of individuals.
“It’s about putting the data first and letting the mathematics follow,” Bortz said.
Cells to particles
In the current study, he and his colleagues, including biochemistry graduate student Graycen Wheeler, decided to turn that data-driven lens to the problem of cell migration.
Liu and his colleagues have observed how skin cells surge together as a group in the lab. Migrating skin cells, they found, tend to follow certain rules: Like a herd of stampeding buffalo, skin cells will align their direction to the cells in front of them but also try not to bump into the leaders from behind.
To see if WSINDy could shed light on this mass movement, Bortz and Messenger designed computer simulations showing hundreds of digital cells moving in tandem. The team deployed their WSINDy approach to build precise equations describing the motion of each and every one of those cells.
“With WSINDy, if you have 1,000 cells, you can learn 1,000 different models,” Bortz said.
They then drew on even more math to begin clustering those models together. Bortz noted that WSINDy is especially well-suited to finding the patterns hiding in data. When the researchers, for example, mixed together two or more types of cells that moved in different ways, their suite of tools could accurately spot and sort the cells into groups.
“We not only learn models for each cell, but those models can be sorted, thus revealing the dominant categories of cell behaviors that play a role in wound healing,” Messenger said.
Moving forward, the collaborators hope to use their approach to start digging into the behavior of real cells in the lab. Liu noted that the technique could be especially useful for studying cancer. Cancer cells, he said, undergo similar mass migrations when they spread from one organ to another.
“As biochemists, we usually don’t have a quantitative way to describe this cell migration,” Liu said. “But now, we do.”
A team of researchers at Shanghai Jiao Tong University, working with a pair of colleagues from Harvard University, has developed a new way to synthesize single quantum nanomagnets that are based on metal-free, multi-porphyrin systems. In their paper published in the journal Nature Chemistry, the group describes their method and possible uses for it.
Molecular magnets are materials that are capable of exhibiting ferromagnetism. They are different from other magnets because their building blocks are composed of organic molecules or a combination of coordination compounds. Chemists have been studying their properties with the goal of using them to develop medical therapies such advanced magnetic resonance imaging, new kinds of chemotherapy and possibly magnetic-field-induced local hyperthermia therapy. In this new effort, the researchers have developed a way to create molecular nanomagnets with quantum properties.
The technique involved first synthesizing a monoporphyrin using what they describe as conventional “solution chemistry”—the monoporhyrins were created by using an atomic-force microscope to pull hydrogen atoms off of polyporphyrins. The researchers then applied the result to a base of gold, which they placed in an oven and heated to 80 °C. This forced the rings in the material to become chained. They then turned the oven up to 290°C and then let the material cook for another 10 minutes. This resulted in the formation of additional carbon cycles and the creation of quantum nanomagnets.
The technique works because it involves the use of porphyrins, which are heterocyclic molecules that have multiple double-bonds with delocalized electrons. They typically exist as rings. They also easily form complexes with ions and rare earth metals, which allows them to be used to create molecular magnets.
Once their magnets were complete, the researchers studied them using a scanning-tunneling microscope, finding ferromagnetic interactions between spins of 15 millielectronvolts. They further confirmed the existence of magnetic interaction exchange using spectroscopy with spin circulation.
The researchers suggest their approach is a relatively easy way to make polyporphyrin quantum nanomagnets of variable lengths, which can also have differing numbers of radical centers.
A new method to ensure consistency and quality in rubber manufacturing, developed by a research team from the University of Tennessee, Knoxville, and Eastman, is likely to show real-world impact on material sustainability and durability for products such as car tires.
As consumers in the U.S. and around the globe are increasingly incentivized toward electric vehicles and away from fossil-fuel reliance, current EV users have uncovered an unexpected maintenance issue. Due to the combination of higher weight and higher torque, EVs put more pressure on standard tires, causing them to degrade 30% faster than tires on internal-combustion vehicles.
UT’s Fred N. Peebles Professor and IAMM Chair of Excellence Dayakar Penumadu, along with electrical engineering graduate student Jun-Cheng Chin, postdoctoral researcher Stephen Young and three Eastman scientists, recently published research aimed at resolving one of rubber manufacturing’s most common challenges: identifying flaws in the material.
Rubber contains additives such as zinc oxide and sulfur that work to improve strength, elasticity and other favorable traits. When the ingredients are not distributed evenly throughout a rubber product such as a car tire, the material will contain flaws that cause the product to degrade prematurely.
“If components such as sulfur do not disperse well, that generates localized hard spots,” said Penumadu. “That hard stuff attracts a lot of mechanical and thermal stresses, making the material degrade prematurely.”
Even a flaw the width of a human hair can decrease the life span of a large rubber component such as a car tire.
“That leads to safety and economic impacts,” Penumadu said.
Identifying and studying such flaws—a field known as fracture mechanics—is critical to understanding how the material will perform. Yet finding such flaws before they cause problems is an issue that has long plagued the rubber industry.
“The current industry approach is to cut out a small sample of rubber, then observe it under an optical microscope,” Penumadu said. “Not only is this tedious and destructive, it’s unreliable. It requires you to guess beforehand where, in an opaque sample, you need to check for inconsistencies.”
In addition, optical microscopes cannot differentiate between rubber components—for example, sulfur and zinc oxide both appear as white specks.
Penumadu’s team has overcome this issue by switching from optical analysis to X-ray computed tomography. X-rays that pass through the sample are scattered and absorbed differently depending on the materials they strike. A computer then reconstructs a digital 3D model of the rubber’s interior.
“This is a very important point,” Penumadu said. “XCT lets us see the inside of the material noninvasively, and we can actually see the distribution of each component.”
The application of this new method increases the rubber industry’s ability to view and predict flaws and will ultimately lead to more consistent quality and longer-lasting rubber products.
In October the team received the 2021 Publication Excellence Award from the Journal of Rubber Chemistry and Technology for their groundbreaking paper, “Sulfur Dispersion Quantitative Analysis in Elastomeric Tire Formulations by Using High Resolution X-Ray Computed Tomography”, which discusses the new XCT method and their research findings.
Glycolipids, basically “fatty sweet” molecules, are a relatively unknown group of lipids. A new method developed by an Austrian team led by chemist Evelyn Rampler of the University of Vienna has now provided deeper insights into the functioning of certain glycolipids located on the surfaces of stem cells. The approach presented by the researchers from the University of Vienna, BOKU Vienna and the University of Graz in the open access Journal of the American Chemical Society Au can be applied to a wide range of glycolipid classes.
Pioneering developments in glycoscience for determining the function of sugar structures on cell surfaces recently received recognition with the Nobel Prize in Chemistry awarded to Carolyn Bertozzi. However, research into the class of fatty sweet molecules known as glycolipids is a relatively new, emerging field of study. With their recent work, chemist Evelyn Rampler of the University of Vienna and her colleagues are providing important basic research for this area. Using highly sensitive tools such as mass spectrometry, the structural properties of glycolipids can be investigated.
Decoding of gangliosides
This study aimed at developing a measurement and data analysis method for a specific class of relatively unknown glycolipids, so-called gangliosides, whose composition changes on the cell membrane during stem cell differentiation.
“Previous approaches have not been able to determine the multiple functions of gangliosides in Alzheimer’s disease, dementia or cancer because they lacked the necessary sensitivity. With our new method, we now provide a tool for the comprehensive analysis of gangliosides,” says Evelyn Rampler, group leader at the Institute of Analytical Chemistry at the University of Vienna.
A research consortium of the Medical University Vienna and the University of Vienna will now investigate the relevance of gangliosides and other fatty sweet molecules in cancer. To monitor sugar structures on cells in even greater detail, it would be also possible to combine this new method with the bioorthogonal labeling introduced by Nobel Prize winner Carolyn Bertozzi.
Study of human stem cells
“Our study on human stem cells has shown that the existing patterns of gangliosides change massively depending on which cells or tissues develop from the stem cells. It was therefore possible to identify new markers for different cell types, which now have to be confirmed in independent studies including larger sample sizes,” says Evelyn Rampler.
“Based on our new mass spectrometry method, we were able to measure and describe the molecular diversity of gangliosides in an unprecedented level of detail,” says first author and chemist Katharina Hohenwallner from the University of Vienna.
The study involved experiments with stem cells, carried out by Dominik Egger of the Institute of Cell and Tissue Culture Technologies at BOKU Vienna. In addition, the software “Lipid Data Analyzer” for gangliosides was adapted together with researchers from the University of Graz, Institute of Pharmaceutical Sciences.
Surgical tissue waste as samples
For the analysis, the team used tissue samples derived from medical waste. First, the so-called mesenchymal stem cells were isolated from the tissue and allowed to differentiate into bone, cartilage, and fat cells. In the course of the study, the largest number of gangliosides were identified to date.
Additionally, gangliosides were identified as potential markers to distinguish the different cell types at the chemical level. Based on automated data analysis, the researchers provide a method to comprehensively measure and structurally describe the gangliosides for the first time.
To guide the design and synthesis of electrocatalysts toward highly efficient oxygen evolution reactions (OER), researchers from the Beijing University of Chemical Technology have summarized four common strategies to improve the OER performance of layered double hydroxides (LDHs) as well as identifying active sites for LDHs.
They published their work on Sep. 7 in Energy Material Advances.
“With the rising demand and consumption of fossil fuels, energy shortage and environmental pollution are becoming severe and unignorable,” said the corresponding author Mingfei Shao, professor with the State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing. “It is necessary to explore sustainable and renewable energy. Hydrogen, especially, is a new energy with splendid application prospects.”
Production of highly pure hydrogen can be achieved by electrochemical water splitting using the electricity transformed from renewable energies such as wind and solar. But as one of the half reactions, OER is a four-electron process, with a low-efficiency energy utilization, according to Shao.
Shao and his team focus on LDHs, a large type two-dimensional material. The wide tunability, molar ratios and interlayer anions, make it an outstanding catalysts for OER in alkaline medias.
“We summarized four common strategies applied to improve the OER performance of LDHs. Through these strategies, the overpotential of OER can be decreased, leading to a high efficiency of energy utilization,” Shao said. “Some works about the identification of active sites for LDHs are introduced. Revelation of reaction mechanism and active sites provide the theoretical guidance to design efficient electrocatalysts.”
The development and exploration of OER catalysts is mostly in the experimental stage at present, which cannot meet the standards for large-scale practical use. For instance, problems related to enlarging the size of the catalysts and maintaining stability during OER remain. Additionally, most reported preparation methods of LDH-based catalysts are complicated and time-consuming, which results in high costs and restricts their application, according to Shao.
“The recognition of reactive oxygen species such as oxygen species adsorbed by active sites on the surface of electrocatalysts and oxygen radical dispersed in the solution during OER still remains ambiguous due to the instable and unapparent existence of reactive oxygen species,” Shao said. “After recognizing these reactive oxygen species, how to take advantage of them for more efficient OER is still vital.”
“We hope this review can offer ideas to further identify the active sites for LDHs with the purpose of providing guidance to design more advanced electrocatalysts towards electrochemical water splitting,” Shao said.
A research team affiliated with UNIST recently reported that the performance of electrodes for an alkaline hydrogen evolution reaction (HER) can be significantly improved even without expensive electrocatalysts and complicated processes by modifying them with superaerophobic polymeric hydrogels. This breakthrough has been led by Professor Jungki Ryu and his research team in the Department of Energy Engineering at UNIST.
In this study, the research team reported a simple strategy to enhance the efficiency of electrochemical hydrogen production by imparting superaerophobicity to an underlying electrode with porous polymeric hydrogels. Superaerophobic hydrogels were readily coated on target substrates by cross-linking polyethyleneimine (PEI) via Schiff-base condensation reactions followed by freeze-drying, noted the research team.
As a result, they could readily control the pore size, porosity, and superaerophobicity of the hydrogel-coated electrodes by varying the concentrations of PEI upon cross-linking. Due to facile removal of as-generated hydrogen bubbles, the NF electrode modified with PEI hydrogel only outperformed those modified with expensive electrocatalysts especially at high current densities, according to the research team.
“We believe that our results can pave the way for the practical application of water electrolysis by providing insights into the design of electrodes and electrolyzers,” noted the research team.
This study has been published in Advanced Energy Materials.
Researchers have discovered a potential new method for making the high-performance magnets used in wind turbines and electric cars without the need for rare earth elements, which are almost exclusively sourced in China.
A team from the University of Cambridge, working with colleagues from Austria, found a new way to make a possible replacement for rare-earth magnets: tetrataenite, a “cosmic magnet” that takes millions of years to develop naturally in meteorites.
Previous attempts to make tetrataenite in the laboratory have relied on impractical, extreme methods. But the addition of a common element—phosphorus—could mean that it’s possible to make tetrataenite artificially and at scale, without any specialized treatment or expensive techniques.
The results are reported in the journal Advanced Science. A patent application on the technology has been filed by Cambridge Enterprise, the University’s commercialization arm, and the Austrian Academy of Sciences.
High-performance magnets are a vital technology for building a zero-carbon economy, and the best permanent magnets currently available contain rare earth elements. Despite their name, rare earths are plentiful in Earth’s crust. However, China has a near monopoly on global production: in 2017, 81% of rare earths worldwide were sourced from China. Other countries, such as Australia, also mine these elements, but as geopolitical tensions with China increase, there are concerns that rare earth supply could be at risk.
“Rare earth deposits exist elsewhere, but the mining operations are highly disruptive: you have to extract a huge amount of material to get a small volume of rare earths,” said Professor Lindsay Greer from Cambridge’s Department of Materials Science & Metallurgy, who led the research. “Between the environmental impacts, and the heavy reliance on China, there’s been an urgent search for alternative materials that do not require rare earths.”
Tetrataenite, an iron-nickel alloy with a particular ordered atomic structure, is one of the most promising of those alternatives. Tetrataenite forms over millions of years as a meteorite slowly cools, giving the iron and nickel atoms enough time to order themselves into a particular stacking sequence within the crystalline structure, ultimately resulting in a material with magnetic properties approaching those of rare-earth magnets.
In the 1960s, scientists were able to artificially form tetrataenite by bombarding iron-nickel alloys with neutrons, enabling the atoms to form the desired ordered stacking, but this technique is not suitable for mass production.
“Since then, scientists have been fascinated with getting that ordered structure, but it’s always felt like something that was very far away,” said Greer. Despite many attempts over the years, it has not yet been possible to make tetrataenite on anything approaching an industrial scale.
Now, Greer and his colleagues from the Austrian Academy of Sciences and the Montanuniversität in Leoben, have found a possible alternative that doesn’t require millions of years of cooling or neutron irradiation.
The team were studying the mechanical properties of iron-nickel alloys containing small amounts of phosphorus, an element that is also present in meteorites. The pattern of phases inside these materials showed the expected tree-like growth structure called dendrites.
“For most people, it would have ended there: nothing interesting to see in the dendrites, but when I looked closer, I saw an interesting diffraction pattern indicating an ordered atomic structure,” said first author Dr. Yurii Ivanov, who completed the work while at Cambridge and is now based at the Italian Institute of Technology in Genoa.
At first glance, the diffraction pattern of tetrataenite looks like that of the structure expected for iron-nickel alloys, namely a disordered crystal not of interest as a high-performance magnet. It took Ivanov’s closer look to identify the tetrataenite, but even so Greer says it’s strange that no one noticed it before.
The researchers say that phosphorus, which is present in meteorites, allows the iron and nickel atoms to move faster, enabling them to form the necessary ordered stacking without waiting for millions of years. By mixing iron, nickel and phosphorus in the right quantities, they were able to speed up tetrataenite formation by between 11 and 15 orders of magnitude, such that it forms over a few seconds in simple casting.
“What was so astonishing was that no special treatment was needed: we just melted the alloy, poured it into a mold, and we had tetrataenite,” said Greer. “The previous view in the field was that you couldn’t get tetrataenite unless you did something extreme, because otherwise you’d have to wait millions of years for it to form. This result represents a total change in how we think about this material.”
While the researchers have found a promising method to produce tetrataenite, more work is needed to determine whether it will be suitable for high-performance magnets. The team are hoping to work on this with major magnet manufacturers.
The work may also force a revision of views on whether the formation of tetrataenite in meteorites really does take millions of years.
