A Cu-organic interface constructed by in situ reconstruction of Cu phthalocyanine can direct the selectivity of CO electrolysis to a specific multicarbon product, with an acetate Faradaic efficiency (FE) as high as 84.2 %, a record acetate partial current density of 605 mA cm−2, and an acetate yield up to 63.4 %. The impressive acetate selectivity is ascribed to the favorable reaction microenvironment created by the Cu-organic interface.
Alkaline CO2 electrolysis can produce multicarbon (C2+) products such as ethylene and acetate, yet suffers from low CO2 utilization efficiency.
Tandem electrolysis, which connects solid oxide or acidic CO2 electrolysis to CO and alkaline CO electrolysis to C2+ products in sequential electrolyzers, is a carbon-efficient route. However, to date, CO electrolysis generally shows high current density and selectivity for C2+ products, but selective generation of a specific C2+ product is still challenging.
Recently, a research team led by Profs. Wang Guoxiong and Gao Dunfeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has proposed a new strategy by constructing metal-organic interfaces for CO electrolysis to acetate with high selectivity.
The researchers tuned the reaction microenvironments surrounding catalytically active sites by constructing Cu-organic interfaces through in-situ electrochemical reconstruction of molecular Cu complexes. Benefiting from the favorable reaction microenvironment, they achieved good catalytic performance for CO electrolysis to acetate, in terms of current density, Faradaic efficiency, and yield.
With a copper phthalocyanine (CuPc) electrode measured in a home-made alkaline membrane electrode assembly (MEA) electrolyzer, they obtained an acetate Faradaic efficiency as high as 84.2% and an acetate carbon selectivity of 92.1% at 500 mA cm-2. The maximum acetate partial current density and formation rate reached 605 mA cm-2 and 0.38 mmol min-1, respectively, translating into an acetate yield as high as 63.4%.
The Cu-organic interface created a favorable reaction microenvironment that enhanced *CO adsorption, lowered the energy barrier for C-C coupling, and facilitated the formation of CH3COOH over other multicarbon products, thus rationalizing the selective acetate production.
“Our study highlights the potential of constructing metal-organic interfaces for tailoring reaction microenvironments for highly selective production of a specific C2+ product from CO electrolysis,” said Prof. Gao.
More information: Youwen Rong et al, Directing the Selectivity of CO Electrolysis to Acetate by Constructing Metal‐Organic Interfaces, Angewandte Chemie International Edition (2023). DOI: 10.1002/anie.202309893
Photographs of the textile samples pegged on the wire fences submerged in the flumes. A – sports vest squares, B & C – fleece squares, D & E – carpet squares. Credit: Forensic Science International (2023). DOI: 10.1016/j.forsciint.2023.111818
Forensic fibers can survive underwater for much longer than previously thought—which could help criminal investigators uncover vital evidence.
New research led by Staffordshire University’s Centre for Crime, Justice and Security has found that fiber evidence can survive on fabrics underwater for several weeks.
Claire Gwinnett, Professor of Forensic and Environmental Science, explained, “Evidence, such as weapons and victim’s bodies, are often found in aquatic environments including rivers and lakes.”
“However, if items have been submerged in water for more than seven days then many forensic examiners believe that any valuable trace evidence will be gone and won’t seek it out.”
To date, very few studies have investigated fiber persistence on fabrics submerged underwater. The dynamic nature of aquatic environments mean that the studies are difficult to conduct in situ and variables, such as water flow rate, are not possible to control.
The Forensic Fiber Freshwater (3F) project was conducted in partnership with Lunz Mesocosm Infrastructure (LMI), WasserCluster Lunz, the University of Vienna and Italy’s University of Milano-Bicocca.
This study used artificial streams, known as mesocosms, to investigate the persistence rate of polyester fibers on different fabric types over a four-week exposure time.
Usually used for ecological research, this is the first time that mesocosms have been employed to look at forensic evidence.
Two flow velocities, high and low, were used on three textiles: woolen/nylon mix carpet, 100% polyester fleece, and 95% polyester/5% elastane sports vest.
Initial loss rates were highest for the first hour of submergence for the carpet, fleece and sports vest. However, persistence rates remained mostly constant after 24 hours for all textiles and the two flow rates used did not significantly affect fiber persistence.
Ph.D. researcher Afsané Kruszelnicki said, “It would be expected that a higher flow rate would have a lower number of retained fibers compared to a lower flow rate, yet no significant difference was seen in all but one condition.”
“Even after four weeks, the lowest percentage of remaining fibers was 33.4%. This clearly indicates that it is extremely valuable to search for fiber evidence even after a long exposure time.”
Professor Gwinnett said, “Our findings could change how police direct investigations and help to uncover forensic evidence that was previously thought to be lost. We hope this will help investigators to identify more suspects and ultimately lead to more convictions.”
“The study also highlights the benefits of using mesocosms which mimic realistic aquatic environments in a controlled setting. This is the first time that mesocosms have been used to look at forensic evidence and we hope it will pave the way for further studies to investigate different types of trace evidence such as gunshot residue, pollen, fingerprints or DNA.”
Dr. Katrin Attermeyer, coordinator of the stream mesocosms in Lunz am See and aquatic microbial ecologist at WasserCluster Lunz and the University of Vienna, added, “This interdisciplinary collaboration between forensic scientists and aquatic ecologists has not only provided insights into other sciences, but has also shown that mesocosms, traditionally used to answer ecological questions, are a valuable asset to other research areas such as forensic sciences.”
The findings are published in the journal Forensic Science International.
More information: Afsané Kruszelnicki et al, An investigation into the use of riverine mesocosms to analyse the effect of flow velocity and recipient textiles on forensic fibre persistence studies, Forensic Science International (2023). DOI: 10.1016/j.forsciint.2023.111818
Exploring the best condition for a black box function by GPT or Bayesian optimization. The solid line represents the mean of the best value obtained in three independent trials; the semitransparent filled range represents the standard deviation; each raw trial is indicated by a semitransparent line. Credit: Science and Technology of Advanced Materials: Methods (2023). DOI: 10.1080/27660400.2023.2260300
GPT-4, the latest version of the artificial intelligence system from OpenAI, the developers of Chat-GPT, demonstrates considerable usefulness in tackling chemistry challenges, but still has significant weaknesses. “It has a notable understanding of chemistry, suggesting it can predict and propose experimental results in ways akin to human thought processes,” says chemist Kan Hatakeyama-Sato, at the Tokyo Institute of Technology.
GPT-4, which stands for Generative Pre-trained Transformer 4, belongs to a category of artificial intelligence systems known as large language models. These can gather and analyze vast quantities of information in search of solutions to challenges set by users. One advance for GPT-4 is that it can use information in the form of images in addition to text.
Although the specific datasets used for training GPT-4 have not been disclosed by its developers, it has clearly learned a significant amount of detailed chemistry knowledge. To analyze its capabilities, the researchers set the system a series of chemical tasks focused on organic chemistry—the chemistry of carbon-based compounds. These covered basic chemical theory, the handling of molecular data, predicting the properties of chemicals, the outcome of chemical processes and proposing new chemical procedures.
The results of the investigation were varied, revealing both strengths and significant limitations. GPT-4 displayed a good understanding of general textbook-level knowledge in organic chemistry. It was weak, however, when set tasks dealing with specialized content or unique methods for making specific organic compounds. It displayed only partial efficiency in interpreting chemical structures and converting them into a standard notation. One interesting feat was its ability to make accurate predictions for the properties of compounds that it had not specifically been trained on. Overall, it was able to outperform some existing computational algorithms, but fell short against others.
“The results indicate that GPT-4 can tackle a wide range of tasks in chemical research, spanning from textbook-level knowledge to addressing untrained problems and optimizing multiple variables,” says Hatakeyama-Sato. “Inevitably, its performance relies heavily on the quality and quantity of its training data, and there is much room for improvement in its inference capabilities.”
The researchers emphasize that their work was only a preliminary investigation, and that future research should broaden the scope of the trials and dig deeper into the performance of GPT-4 in more diverse research scenarios.
They also hope to develop their own large language models specializing in chemistry and explore their integration with existing techniques.
“In the meantime, researchers should certainly consider applying GPT-4 to chemical challenges, possibly using hybrid methods that include existing specialized techniques,” Hatakeyama-Sato concludes.
More information: Kan Hatakeyama-Sato et al, Prompt engineering of GPT-4 for chemical research: what can/cannot be done?, Science and Technology of Advanced Materials: Methods (2023). DOI: 10.1080/27660400.2023.2260300
Cocoa pods, like this one with parts of the husk removed for analyses, could be a useful starting material for flame retardants. Credit: Dimitris Charalampopoulos
As Halloween approaches, so too does the anticipation of a trick-or-treating stash filled with fun-sized chocolate candy bars. But to satisfy our collective craving for this indulgence, millions of cocoa pods are harvested annually. While the beans and pulp go to make chocolate, their husks are thrown away. Now, researchers reporting in ACS Sustainable Chemistry & Engineering show that cocoa pod husks could be a useful starting material for flame retardants.
It’s estimated that about 24 million tons of leftover cocoa pod husks are produced yearly. Waste husks have been explored as a source of carbohydrates and sugars, but they also contain lignin, a tough lipid polymer found in many woody plants. And lignin could be a renewable replacement for some substances typically derived from petroleum, such as flame retardants.
While most methods to produce lignin have centered on hardwood trees, some scientists have processed other plant materials that would otherwise go to waste, such as rice husks and pomegranate peels. So, Nicholas J. Westwood and coworkers wanted to see if high-quality lignin could be extracted from cocoa pod husks and determine whether it has the potential to make valuable, practical materials.
The researchers obtained cocoa husks and milled them into a powder. After rinsing to remove fatty residues, they boiled the powdered husks in a mixture of butanol and acid, a standard lignin extraction method called the butanosolv process. They next confirmed the isolated lignin’s quality and high purity, finding no evidence of carbohydrates or other contaminants.
Then, over the course of three chemical steps, the team modified the pure lignin biopolymer to have flame-retardant properties. They attached 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, which is a fire suppressant molecule called DOPO, into the backbone of the lignin polymer.
In experiments, when the modified lignin was heated, it charred—but did not burn up—a sign that it could act as a flame retardant. The researchers recognize that human safety tests are important and plan to conduct them after the next phase of testing. In the future, the researchers say they will optimize the properties of their cocoa pod husk-based flame-retardant materials.
More information: Daniel J. Davidson et al, Organosolv Pretreatment of Cocoa Pod Husks: Isolation, Analysis, and Use of Lignin from an Abundant Waste Product, ACS Sustainable Chemistry & Engineering (2023). DOI: 10.1021/acssuschemeng.2c03670
Human nose structure 3D printed with a support material. Credit: Shinji Sakai
What if organ damage could be repaired by simply growing a new organ in the lab? Improving researchers’ ability to print live cells on demand into geometrically well-defined, soft complex 3D architectures is essential to such work, as well as for animal-free toxicological testing.
In a study recently published in ACS Biomaterials Science and Engineering, researchers from Osaka University have overcome prior limitations that have hindered cell growth and the geometrical fidelity of bioprinted architectures. This work might help bring 3D-printed cell constructs closer to mimicking biological tissue and organs.
Ever since bioprinting was first reported in 1988 by using a standard inkjet printer, researchers have explored the potential of this layer-by-layer tissue assembly procedure to regrow damaged body parts and test medical hypotheses. Bioprinting is to eject a cell-containing “ink” from a printing nozzle to form 3D structures. It is usually easier to print hard rather than soft structures. However, soft structures are preferable in terms of cell growth in the printed structures.
When printing soft structures, doing so in a printing support is effective; however, solidification of ink in the support filled in a vessel can result in its contamination with unwanted substances from the support. Ink solidification into a soft matrix using a printing support without contamination, while retaining cell viability, was the goal of this work.
“In our approach, a 3D printer alternately dispenses the cell-containing ink and a printing support,” explains Takashi Kotani, lead author of the study. “The interesting point is that the support also plays a role in facilitating the solidification of the ink. All that’s necessary for ink solidification is in the support, and after removing the support, the geometry of the soft printed cell structures remains intact.”
Hydrogen peroxide from the support enabled an enzyme in the ink to initiate gelation of the ink, resulting in a gel-enclosed cell assembly within a few seconds. This rapid gelation prevented contamination of the assembly during formation. After removing the support, straightforward 3D constructs such as inverted trapezium geometries as well as human nose shapes—including bridges, holes, and overhangs—were readily obtained.
“We largely retain mouse fibroblast cell geometry and growth, and the cells remain viable for at least two weeks,” says Shinji Sakai, senior author. “These cells also adhere to and proliferate on our constructs, which highlights our work’s potential in tissue engineering.”
This new technique is an important step forward to engineering human cell assemblies and tissues. Further work might involve further optimizing the ink and support, as well as incorporating blood vessels into the artificial tissue to improve its resemblance to physiological architectures. Regenerative medicine, pharmaceutical toxicology, and other fields will all benefit from this work and further improvements in the precise fidelity of bioprinting.
More information: Takashi Kotani et al, Horseradish Peroxidase-Mediated Bioprinting via Bioink Gelation by Alternately Extruded Support Material, ACS Biomaterials Science & Engineering (2023). DOI: 10.1021/acsbiomaterials.3c00996
a CMC/cellulose composite systems with and without FT treatments and appearance of fresh hydrogel and freeze-dried foams. b The swelling ratio of H1 and H2 solid foams. c The responsive behavior of solid foams in NaOH solution (0.1 N). Credit: Advanced Composites and Hybrid Materials (2023). DOI: 10.1007/s42114-023-00745-x
Using a small bird’s nest-making process as a model, researchers from North Carolina State University have developed a nontoxic process for making cellulose gels. The freeze-thaw process is simple, cost-effective, and can create cellulose gels that are useful in a number of applications, including tunable gels for timed drug delivery. The process also works with bamboo and potentially other lignin-containing plant fibers.
The work appears in Advanced Composites and Hybrid Materials. Noureddine Abidi of Texas Tech University is a co-corresponding author of the work.
Cellulose is a wonderful material for making hydrogels—which are used in applications ranging from contact lenses to wound care and drug delivery. But creating hydrogels from cellulose is tricky, and often the processes used to create the hydrogels are themselves toxic.
“Normally, you have to first dissolve the cellulose and then induce it to crosslink or form the structure of interest, which often requires the use of difficult to handle, unstable, or toxic solvents,” says Lucian Lucia, professor of forest biomaterials and chemistry at NC State and co-corresponding author of the work.
Enter the swift family of birds—small birds who use their saliva to hold twigs in place when building their nests.
“My then-Ph.D. student Zhen Zhang noted that when birds do this, the saliva acts like a natural resin that holds the nest together and encourages the fibers within the nest to interconnect or crosslink,” Lucia says. “Which is exactly what we want the dissolved cellulose to do when making hydrogels. So we asked ourselves, ‘What if we mimic the birds?'”
Zhang, currently a postdoc at Texas Tech University, is a co-corresponding author.
The researchers added a water soluble cellulose called carboxymethyl cellulose (CMC) to an acid solution and dissolved the CMC. Then they added powdered cellulose fiber to the solution and subjected it to four rounds of freezing and thawing. The result was cellulose gel.
“Think of it as adding a thickener to water, like you would a pie filling,” Lucia says. “By changing the pH of the CMC, the water essentially becomes sticky. Freezing and thawing the solution causes the cellulose to compact and interweave itself into the sticky network, giving you a more organized structure, just as swifts do when they create their nests. Only we don’t have to use beaks and saliva to do it.”
Freeze drying the gels resulted in cellulose foam. The researchers repeated the process with bamboo fibers as well, which suggests that it could be useful with many other lignin– and cellulose-containing fibers.
“The cellulose gels are robust, stable at room temperature and can be tuned to degrade on a schedule, so would be useful in drug delivery applications, among others,” Lucia says. “This opens a promising new window for using biomimicry to process these insoluble cellulosic materials in a greener way.”
More information: Zhen Zhang et al, A “bird nest” bioinspired strategy deployed for inducing cellulose gelation without concomitant dissolution, Advanced Composites and Hybrid Materials (2023). DOI: 10.1007/s42114-023-00745-x
Graphical abstract. Credit: Journal of the American Chemical Society (2023). DOI: 10.1021/jacs.3c06500
The DNA double helix is composed of two DNA molecules whose sequences are complementary to each other. The stability of the duplex can be fine-tuned in the lab by controlling the amount and location of imperfect complementary sequences.
Fluorescent markers bound to one of the matching DNA strands make the duplex visible, and fluorescence intensity increases with increasing duplex stability. Now, researchers at the University of Vienna succeeded in creating fluorescent duplexes that can generate any of 16 million colors—a work that surpasses the previous 256 colors limitation.
The unique ability of complementary DNA sequences to recognize and assemble as duplexes is the biochemical mechanism for how genes are read and copied. The rules of duplex formation (also called hybridization) are simple and invariable, making them predictable and programmable too.
Programming DNA hybridization allows for synthetic genes to be assembled and large-scale nanostructures to be built. This process always relies on perfect sequence complementarity. Programming instability vastly expands our ability to manipulate molecular structure and has applications in the field of DNA and RNA therapeutics.
In this novel study, researchers at the Institute of Inorganic Chemistry at the University of Vienna showed that controlled hybridization can result in the creation of 16 million colors and can accurately reproduce any digital image in DNA format.
(Left) The original digital image (in standard 24-bit color depth). (Right) The picture “photocopied” in DNA format by the authors. Credit: cblee, Trey Ratcliff, stewartbaird and NOAA Ocean Exploration & Research Right, Tadija Kekic and Jory Lietard
A canvas the size of a fingernail
To create color, different small DNA strands linked to fluorescent molecules (markers) that can emit either red, green or blue color are hybridized to a long complementary DNA strand on the surface. To vary the intensity of each color, the stability of the duplex is lowered by carefully removing bases of the DNA strand at pre-defined positions along the sequence.
With lower stability comes a darker shade of color, and fine-tuning this stability results in the creation of 256 shades for all color channels. All shades can be mixed and matched within a single DNA duplex, thus generating 16 million combinations and matching the color complexity of modern digital images. To achieve this level of precision in DNA-to-color conversion, > 45,000 unique DNA sequences had to be synthesized.
To do so, the research team used a method for parallel DNA synthesis called maskless array synthesis (MAS). With MAS, hundreds of thousands of unique DNA sequences can be synthesized at the same time and on the same surface, a miniature rectangle the size of a fingernail.
Since the approach allows the experimenter to control the location of any DNA sequence on that surface, the corresponding color can also be selectively assigned to a chosen location. By automating the process using dedicated computer scripts, the authors were able to transform any digital image into a DNA photocopy with accurate color rendition. “Essentially, our synthesis surface becomes a canvas for painting with DNA molecules at the micrometer scale,” says Jory Lietard, PI in the Institute of Inorganic Chemistry.
Resolution is currently limited to XGA, but the reproduction process is applicable to 1080p, as well as potentially 4K image resolution. “Beyond imaging, a DNA color code could have very useful applications in data storage on DNA,” says Tadija Kekić, Ph.D. candidate in the group of Jory Lietard. As evidenced by the 2023 Nobel Prize attributed to the development of quantum dots, the chemistry of color has a bright future ahead.
More information: Tadija Kekić et al, A Canvas of Spatially Arranged DNA Strands that Can Produce 24-bit Color Depth, Journal of the American Chemical Society (2023). DOI: 10.1021/jacs.3c06500
A sample of a DUCKY polymer membrane researchers created to perform the initial separation of crude oils using significantly less energy. Credit: Candler Hobbs, Georgia Institute of Technology
A new kind of polymer membrane created by researchers at Georgia Tech could reshape how refineries process crude oil, dramatically reducing the energy and water required while extracting even more useful materials.
The so-called DUCKY polymers—more on the unusual name in a minute—are reported in Nature Materials. And they’re just the beginning for the team of Georgia Tech chemists, chemical engineers, and materials scientists. They also have created artificial intelligence tools to predict the performance of these kinds of polymer membranes, which could accelerate development of new ones.
The implications are stark: the initial separation of crude oil components is responsible for roughly 1% of energy used across the globe. What’s more, the membrane separation technology the researchers are developing could have several uses, from biofuels and biodegradable plastics to pulp and paper products.
“We’re establishing concepts here that we can then use with different molecules or polymers, but we apply them to crude oil because that’s the most challenging target right now,” said M.G. Finn, professor and James A. Carlos Family Chair in the School of Chemistry and Biochemistry.
Crude oil in its raw state includes thousands of compounds that have to be processed and refined to produce useful materials—gas and other fuels, as well as plastics, textiles, food additives, medical products, and more. Squeezing out the valuable stuff involves dozens of steps, but it starts with distillation, a water- and energy-intensive process.
Researchers have been trying to develop membranes to do that work instead, filtering out the desirable molecules and skipping all the boiling and cooling.
“Crude oil is an enormously important feedstock for almost all aspects of life, and most people don’t think about how it’s processed,” said Ryan Lively, Thomas C. DeLoach Jr. Professor in the School of Chemical and Biomolecular Engineering. “These distillation systems are massive water consumers, and the membranes simply are not. They’re not using heat or combustion. They just use electricity. You could ostensibly run it off of a wind turbine, if you wanted. It’s just a fundamentally different way of doing a separation.”
What makes the team’s new membrane formula so powerful is a new family of polymers. The researchers used building blocks called spirocyclic monomers that assemble together in chains with lots of 90-degree turns, forming a kinky material that doesn’t compress easily and forms pores that selectively bind and permit desirable molecules to pass through. The polymers are not rigid, which means they’re easier to make in large quantities. They also have a well-controlled flexibility or mobility that allows pores of the right filtering structure to come and go over time.
The DUCKY polymers are created through a chemical reaction that’s easy to produce at a scale that would be useful for industrial purposes. It’s a flavor of a Nobel Prize-winning family of reactions called click chemistry, and that’s what gives the polymers their name. The reaction is called copper-catalyzed azide-alkyne cycloaddition—abbreviated CuAAC and pronounced “quack.” Thus: DUCKY polymers.
In isolation, the three key characteristics of the polymer membranes aren’t new; it’s their unique combination that makes them a novelty and effective, Finn said.
The research team included scientists at ExxonMobil, who discovered just how effective the membranes could be. The company’s scientists took the crudest of the crude oil components—the sludge left at the bottom after the distillation process—and pushed it through one of the membranes. The process extracted even more valuable materials.
“That’s actually the business case for a lot of the people who process crude oils. They want to know what they can do that’s new. Can a membrane make something new that the distillation column can’t?” Lively said. “Of course, our secret motivation is to reduce energy, carbon, and water footprints, but if we can help them make new products at the same time, that’s a win-win.”
Predicting such outcomes is one way the team’s AI models can come into play. In a related study recently published in Nature Communications, Lively, Finn, and researchers in Rampi Ramprasad’s Georgia Tech lab described using machine learning algorithms and mass transport simulations to predict the performance of polymer membranes in complex separations.
“This entire pipeline, I think, is a significant development. And it’s also the first step toward actual materials design,” said Ramprasad, professor and Michael E. Tennenbaum Family Chair in the School of Materials Science and Engineering. “We call this a ‘forward problem,’ meaning you have a material and a mixture that goes in—what comes out? That’s a prediction problem. What we want to do eventually is to design new polymers that achieve a certain target permeation performance.”
Complex mixtures like crude oil might have hundreds or thousands of components, so accurately describing each compound in mathematical terms, how it interacts with the membrane, and extrapolating the outcome is “non-trivial,” as Ramprasad put it.
Training the algorithms also involved combing through all the experimental literature on solvent diffusion through polymers to build an enormous dataset. But, like the potential of membranes themselves to reshape refining, knowing ahead of time how a proposed polymer membrane might work would accelerate a materials design process that’s basically trial-and-error now, Ramprasad said.
“The default approach is to make the material and test it, and that takes time. This data-driven or machine learning-based approach uses past knowledge in a very efficient manner,” he said. “It’s a digital partner: You’re not guaranteed an exact prediction, because the model is limited by the space spanned by the data you use to train it. But it can extrapolate a little bit and it can take you in new directions, potentially. You can do an initial screening by searching through vast chemical spaces and make go, no-go decisions up front.”
Lively said he’d long been a skeptic about the ability of machine learning tools to tackle the kinds of complex separations he works with.
“I always said, ‘I don’t think you can predict the complexity of transport through polymer membranes. The systems are too big; the physics are too complicated. Can’t do it.'”
But then he met Ramprasad: “Rather than just be a naysayer, Rampi and I took a stab at it with a couple of undergrads, built this big database, and dang. Actually, you can do it,” Lively said.
Developing the AI tools also involved comparing the algorithms’ predictions to actual results, including with the DUCKY polymer membranes. The experiments showed the AI models predictions were within 6% to 7% of actual measurements.
“It’s astonishing,” Finn said. “My career has been spent trying to predict what molecules are going to do. The machine learning approach, and Rampi’s execution of it, is just completely revolutionary.”
More information: Nicholas C. Bruno et al, Solution-processable polytriazoles from spirocyclic monomers for membrane-based hydrocarbon separations, Nature Materials (2023). DOI: 10.1038/s41563-023-01682-2
Schematic of solar-driven chemical production by semiconductor biohybrids synthesized from wastewater pollutants using engineered V. natriegens. a, Schematic of chemical production by refinery of fossil fuels, sugar fermentation and biohybrids using wastewater. b, Comprehensive evaluation of sustainability of these routes by CO2 equivalent of GHG emissions, economy of cost advantages and revenue from extended by-products and environmental remediation. c, The industrial wastewater usually contains multipollutants including Cd2+, sulfate and organics. These pollutants could be co-utilized by engineered V. natriegens to construct a biohybrid system for solar-driven chemical production in–situ. Credit: Nature Sustainability (2023). DOI: 10.1038/s41893-023-01233-2
Researchers led by Prof. Gao Xiang from the Shenzhen Institute of Advanced Technology (SIAT) of the Chinese Academy of Sciences and Prof. Lu Lu from the Harbin Institute of Technology have proposed a novel method to transform wastewater contaminants into valuable chemicals using sunlight, thus paving the way for sustainable and eco-friendly chemical manufacturing.
Conventional chemical manufacturing relies on energy-intensive processes. Semiconductor biohybrids, integrating efficient light-harvesting materials with superior living cells, have emerged as an exciting advancement in utilizing solar energy for chemical production. However, the challenge lies in finding an economically viable and environmentally friendly approach to scale up this technology.
In this study, the researchers set out to convert pollutants from wastewater into semiconductor biohybrids directly in the wastewater environment. The concept involves utilizing the organic carbon, heavy metals, and sulfate compounds present in wastewater as the raw materials for constructing these biohybrids, and subsequently converting them into valuable chemicals.
Nevertheless, real industrial wastewater usually varies in its composition of major organic pollutants, heavy metals, and complex pollutants, all of which are often toxic to bacterial cells and difficult for them to metabolize efficiently. It also contains high levels of salt and dissolved oxygen that require bacteria with an aerobic sulfate reduction capacity. Thus, it’s challenging to use wastewater as bacteria feedstock.
To overcome this, the researchers selected a fast-growing marine bacterium, Vibrio natriegens, which has exceptional tolerance for high salt concentration and a capacity for utilizing various carbon sources. They introduced an aerobic sulfate reduction pathway into V. natriegens and trained the engineered strain to utilize different metal and carbon sources in order to produce semiconductor biohybrids directly from such wastewater.
Their primary target chemical for production was 2,3-butanediol (BDO), a valuable commodity chemical.
By engineering a strain of V. natriegens, they generated hydrogen sulfide, which played a pivotal role in facilitating the production of CdS nanoparticles that efficiently absorb light. These nanoparticles, renowned for their biocompatibility, enabled the in-situ creation of semiconductor biohybrids and enabled the non-photosynthetic bacteria to utilize light.
The results showed that these sunlight-activated biohybrids exhibited significantly enhanced BDO production, surpassing yields achievable through bacterial cells alone. Furthermore, the process displayed scalability, achieving solar-driven BDO production on a substantial 5-liter scale using actual wastewater.
“The biohybrid platform not only boasts a lower carbon footprint but also reduces product costs, leading to an overall smaller environmental impact when compared to both traditional bacterial fermentation and fossil fuel-based BDO production methods,” said Prof. Gao. “Remarkably, these biohybrids could be produced using a variety of wastewater sources.”
Structure of MUC1 glycoprotein on surface. A zoomed-in STM image of MUC1 showing the glycan and protein moieties was interpreted to yield molecular structure of MUC1 on surface. Credit: Science (2023). DOI: 10.1126/science.adh3856
A team of organic chemists at the Max-Planck Institute for Solid-State Research, working with colleagues from the University of Tübingen and the University of Copenhagen, reports a way to take pictures of the sequences and locations of glycans (also known as polysaccharides) bound to several biomolecules at the single-molecule level. Their study is published in Science.
Glycans are types of carbohydrates involved in a myriad of biological processes, one of which is protein folding. They are typically found on the exteriors of most cells. Prior research has shown that they can take either a branched or linear form and are made of O-glycosidic linkages of monosaccharides. Because of their importance in both biological processes and research efforts, scientists have been studying them for many years. In this new effort, the research team developed a microscopy method to take pictures of glycans as they bind to proteins.
After conducting a multitude of experiments looking for a way to image glycan binding, the team found one that involved an electrospray technique that pushed glycans bound to lipid and protein molecules (known as glycosaminoglycans and glycoconjugates) onto two metal surfaces—silver and copper. This allowed them to image the molecules directly using scanning tunneling microscopy.
The researchers were able to identify given monosaccharides in a glycan chain, which in turn allowed them to learn more about how the glycans are oriented and their attachment position on protein backbones.
The researchers also demonstrated their new imaging technique by creating pictures of oxygen-linked glycans as they were bound to mucin proteins—images, they note, that could be useful in the search for early cancer biomarkers. The technique could be used in a wide variety of research efforts, perhaps even in helping to find unknown glycolipids and/or glycoproteins.
More information: Kelvin Anggara et al, Direct observation of glycans bonded to proteins and lipids at the single-molecule level, Science (2023). DOI: 10.1126/science.adh3856
