Category Archives: nanotechnology

Cotton gin waste and self-embedding silver nanoparticles

This work may lead to new uses for cotton waste products according to an April 10, 2024 news item on phys.org,

Cotton gin waste, also known as cotton gin trash, is a byproduct of the cotton ginning process and occurs when the cotton fibers are separated from the seed boll. For cotton gin waste, the treasure is its hidden potential to transform silver ions into silver nanoparticles and create a new hybrid material that could be used to add antimicrobial properties to consumer products, like aerogels, packaging, or composites.

An April 9, 2024 US Dept. of Agriculture (USDA) Agricultural Research Service (ARS) news release, which originated the news item, provides more detail, Note: Links have been removed,

Silver nanoparticles are highly sought-after products in the nanotechnology industry because of their antibacterial, antifungal, antiviral, electrical, and optical properties. These nanoparticles have an estimated global production of 500 tons per year and are widely applied to consumer goods such as textiles, coatings, paints, pigments, electronics, optics, and packaging.

In a study published in ACS Omega, researchers from the United States Department of Agriculture (USDA)’s Agricultural Research Service (ARS) revealed the ability of cotton gin waste to synthesize and generate silver nanoparticles in the presence of silver ions.

“Our method not only lets cotton gin waste act as chemical agents for producing silver nanoparticles, which makes it cost-effective and environmentally friendly but also enables embedding the nanoparticles within the cotton gin waste matrix,” said Sunghyun Nam, research engineer at ARS’s Cotton Chemistry and Utilization Research Unit in New Orleans. “By embedding them in the cotton gin waste, these materials acquire antimicrobial properties.”

Nam said the researchers used a simple heat treatment of cotton gin waste materials in water containing silver ions that produced silver nanoparticles without the need for additional chemical agents.

This finding is significant since making silver nanoparticles usually requires chemical agents which can be costly and pose environmental concerns. Embedding nanoparticles into a material can also be challenging.

Developing nanoparticle embedding technology is not new for Nam and her team. They previously developed washable antimicrobial wipes by using raw cotton fiber that produced silver nanoparticles inside the fiber. The embedded silver nanoparticles can continue to kill harmful bacteria wash after wash.

Large quantities of cotton gin waste are generated annually, and the cotton ginning industry is always seeking new sustainable processes that upcycle crop residue.

“Our research paves the way for new material applications of cotton gin waste that can protect against microbial contamination,” said Nam.

A provisional patent application on the self-embedding silver nanoparticle biomass waste compositions has recently been filed.

The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in U.S. agricultural research results in $20 of economic impact.

Despite the date of the news release, this is a relatively old paper; here’s a link to and a citation,

Unveiling the Hidden Value of Cotton Gin Waste: Natural Synthesis and Hosting of Silver Nanoparticles by Sunghyun Nam*, Michael Easson, Jacobs H. Jordan, Zhongqi He, Hailin Zhang, Michael Santiago Cintrón, and SeChin Chang. ACS Omega 2023, 8, 34, 31281–31292 DOI: https://doi.org/10.1021/acsomega.3c03653 Publication Date: August 9, 2023 © 2023 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY-NC-ND 4.0.

As you can see from the Creative Commons licence, this paper is open access.

Nanocellulose film and Kiragami hydrogels

A Kirigami pattern of the hydrogel (top) and the hydrogel swollen from dry state (bottom). (Image: NIMS) [downloaded from https://www.nanowerk.com/nanotechnology-news3/newsid=65005.php]

An April 11, 2024 news item on Nanowerk highlights research that combines kiragami with hydrogel production, Note 1: A link has been removed, Note 2: Kiragami is described in the excerpt after this one,

New options for making finely structured soft, flexible and expandable materials called hydrogels have been developed by researchers at Tokyo University of Agriculture and Technology (TUAT). Their work extends the emerging field of ‘kirigami hydrogels’, in which patterns are cut into a thin film allowing it to later swell into complex hydrogel structures.

An April 12, 2024 Tokyo University of Agriculture and Technology (TUAT) press release, which originated the news item, on JCN Newswire, Note: Distribution of press releases can be spread out over days (sometimes identical press releases are sent out twice, months apart),

Hydrogels have a network of water-attracting (hydrophilic) molecules, allowing their structure to swell substantially when exposed to water that becomes incorporated within the molecular network. Researchers Daisuke Nakagawa and Itsuo Hanasaki worked with an initially dry film composed of nanofibers of cellulose, the natural material that forms much of the structure of plant cell walls.

They used laser processing to cut structures into the film before water was added allowing the film to swell. The particular design of the Kirigami pattern works in such a way that the width increases when stretched in the longitudinal direction, which is called the auxetic property. This auxetic property emerges provided that the thickness grows sufficiently when the original thin film is wet.

“As Kirigami literally means the cut design of papers [emphasis mine], it was originally intended for thin sheet structures. On the other hand, our two-dimensional auxetic mechanism manifests when the thickness of the sheet is sufficient, and this three dimensionality of the hydrogel structure emerges by swelling when it is used. It is convenient to store it in the dry state before use, rather than keeping the same water content level of the hydrogel.” says Hanasaki. “Furthermore, the auxeticity is maintained during the cyclic loading that causes the adaptive deformation of the hydrogel to reach another structural state. It will be important for the design of intelligent materials.”

Potential applications for the adaptive hydrogels include soft components of robotic technologies, allowing them to respond flexibly when interacting with objects they are manipulating, for example. They might also be incorporated into soft switches and sensor components. Hydrogels are also being explored for medical applications, including tissue engineering, wound dressings, drug delivery systems and materials that can adapt flexibly to movement and growth. The advance in kirigami hydrogels achieved by the TUAT team significantly extends the options for future hydrogel applications.

“Keeping the designed characteristics while showing adaptivity to the environmental condition is advantageous for the development of multifunctionality,” Hanasaki concludes

Here’s a link to and a citation for the paper,

Adaptive plasticity of auxetic Kirigami hydrogel fabricated from anisotropic swelling of cellulose nanofiber film by Daisuke Nakagawa & Itsuo Hanasaki. Science and Technology of Advanced Materials Volume 25, 2024 – Issue 1 Article: 2331959 DOI: https://doi.org/10.1080/14686996.2024.2331959 Published online: 02 Apr 2024

This is an open access paper.

Goldene, its single layer of gold atoms makes it a cousin to graphene (a single layer of carbon atoms)

An April 16, 2024 news item on ScienceDaily announces yet another addition to the world of 2D materials,

For the first time, scientists have managed to create sheets of gold only a single atom layer thick. The material has been termed goldene. According to researchers from Linköping University, Sweden, this has given the gold new properties that can make it suitable for use in applications such as carbon dioxide conversion, hydrogen production, and production of value-added chemicals. Their findings are published in the journal Nature Synthesis.

An April 16, 2024 Linköping University press release (also on EurekAlert), which originated the news item, describes the constraints the researchers faced and how they resolved the problem of how to create goldene,

Scientists have long tried to make single-atom-thick sheets of gold but failed because the metal’s tendency to lump together. But researchers from Linköping University have now succeeded thanks to a hundred-year-old method used by Japanese smiths.

“If you make a material extremely thin, something extraordinary happens – as with graphene. The same thing happens with gold. As you know, gold is usually a metal, but if single-atom-layer thick, the gold can become a semiconductor instead,” says Shun Kashiwaya, researcher at the Materials Design Division at Linköping University.

To create goldene, the researchers used a three-dimensional base material where gold is embedded between layers of titanium and carbon. But coming up with goldene proved to be a challenge. According to Lars Hultman, professor of thin film physics at Linköping University, part of the progress is due to serendipidy. 

“We had created the base material with completely different applications in mind. We started with an electrically conductive ceramics called titanium silicon carbide, where silicon is in thin layers. Then the idea was to coat the material with gold to make a contact. But when we exposed the component to high temperature, the silicon layer was replaced by gold inside the base material,” says Lars Hultman.

This phenomenon is called intercalation and what the researchers had discovered was titanium gold carbide. For several years, the researchers have had titanium gold carbide without knowing how the gold can be exfoliated or panned out, so to speak. 

By chance, Lars Hultman found a method that has been used in Japanese forging art for over a hundred years. It is called Murakami’s reagent, which etches away carbon residue and changes the colour of steel in knife making, for example. But it was not possible to use the exact same recipe as the smiths did. Shun Kashiwaya had to look at modifications:

“I tried different concentrations of Murakami’s reagent and different time spans for etching. One day, one week, one month, several months. What we noticed was that the lower the concentration and the longer the etching process, the better. But it still wasn’t enough,” he says.

The etching must also be carried out in the dark as cyanide develops in the reaction when it is struck by light, and it dissolves gold. The last step was to get the gold sheets stable. To prevent the exposed two-dimensional sheets from curling up, a surfactant was added. In this case, a long molecule that separates and stabilises the sheets, i.e. a tenside.

“The goldene sheets are in a solution, a bit like cornflakes in milk. Using a type of “sieve”, we can collect the gold and examine it using an electron microscope to confirm that we have succeeded. Which we have,” says Shun Kashiwaya.

The new properties of goldene are due to the fact that the gold has two free bonds when two-dimensional. Thanks to this, future applications could include carbon dioxide conversion, hydrogen-generating catalysis, selective production of value-added chemicals, hydrogen production, water purification, communication, and much more. Moreover, the amount of gold used in applications today can be much reduced.

The next step for the LiU researchers is to investigate whether it is possible to do the same with other noble metals and identify additional future applications.

Here’s a link to and a citation for the paper,

Synthesis of goldene comprising single-atom layer gold by Shun Kashiwaya, Yuchen Shi, Jun Lu, Davide G. Sangiovanni, Grzegorz Greczynski, Martin Magnuson, Mike Andersson, Johanna Rosen & Lars Hultman. Nature Synthesis (2024) DOI: https://doi.org/10.1038/s44160-024-00518-4 Published: 16 April 2024

This paper is open access.

Three century long development of a scientific idea: body armor made from silk

Credit: Unsplash/CC0 Public Domain [downloaded from https://phys.org/news/2024-04-body-armor-silk-apparently-edge.html]

Lloyd Strickland’s (professor of Philosophy and Intellectual History, Manchester Metropolitan University) fascinating April 9, 2024 essay on The Conversation (h/t April 10, 2024 news item on phys.org) illustrates the long and winding road to scientific and technological discoveries, Note: Links have been removed,

Separate teams of Chinese and American scientists are reported to be developing body armour using the silk from genetically modified silkworms. The researchers modified the genes of silkworms to make them produce spider silk instead of their own silk.

Harnessing the properties of spider silk has been a longstanding aim because the material is as strong as steel, yet also highly elastic. However, the idea of using silk to make bulletproof vests is not a new idea. Instead, it goes back centuries.

The invention of the silk bulletproof vest is often credited to the American physician George Emory Goodfellow (1855–1910), following his observation that silk was impenetrable to bullets.

But the idea was in fact proposed more than two centuries earlier by the German polymath Gottfried Wilhelm Leibniz (1646–1716), best known as inventor of calculus and binary arithmetic. …

You’ll notice it’s almost two centuries between the idea being proposed and someone working out a way to make a silk bulletproof vest. First, Liebniz (from Strickland’s April 9, 2024 essay), Note: Links have been removed,

In one of these little-known writings, unassumingly entitled “Plan for a military manufacturing process”, Leibniz sought to identify a material suitable for making a lightweight, flexible, bulletproof fabric. He briefly considered metal wires, layered metal sheets, and layered “goldbeater’s skin”, which is a material made from ox intestine. However, he devoted most of his attention to silk.

Whereas Goodfellow had observed the impenetrability of silk by bullets, Leibniz never had. Instead, he thought silk was the most promising material for a bulletproof fabric due to being lightweight, flexible, and strong. “Of all the materials we use for fabrics, and which can be obtained in quantity, there is nothing firmer than a silk thread,” he wrote.

Noting that silk was never firmer than in the cocoon, “where the silk is still gathered in the way that nature produced it”, Leibniz proposed making a fabric formed of silkworm cocoons tightly pressed together with a little glue.

He realised that while such a sheet could not easily be pierced, due to the tightly-woven silk in the cocoons, it would be prone to tearing where one cocoon met the next. Thus, he inferred that a bullet would not make a hole in the fabric, but instead tear whatever cocoon it hit from the surrounding ones, and drive it into the body, similar to what Goodfellow would observe with the silk handkerchief two centuries later.

Leibniz’s solution to the tearing problem was to propose layering sheets of pressed silkworm cocoons on top of each other. He illustrated this with a rudimentary diagram of a row of circles stacked on top of one another in a lattice arrangement, where a small interstice is left between adjoining circles.

Layering cocoons in such a hexagonal packing arrangement ensures that the weak parts of one layer are covered by the strong parts of another. This way, the fabric would not tear or be pierced when hit by a bullet. The result, Leibniz claimed, would be a fabric suitable for covering almost the whole body, especially if it was made to be oversized, affording the wearer freedom of movement.

Leibniz never realised his proposal to create bulletproof clothing using silk.

Strickland’s April 9, 2024 essay offers more about how Goodfellow’s field observations led to the invention of the first silk bulletproof vest by a Catholic priest.

Scott Burton’s undated article for bodyarmornews.com on spider silk and bulletproof body armour offers information about current efforts by US and Chinese scientists to incorporate spider proteins by gene editing silkworms capable of producing enough hybrid silk for enhanced body armour.

A century later, what appears to be the latest breakthrough was announced in a September 24, 2023 news item on chinadaily.com (and noted in Burton’s article),

Chinese scientists have developed the first whole full-length spider silk fiber obtained from genetically-engineered silkworms, exhibiting a six-fold toughness when compared to a bulletproof vest.

The results pave the way for spider silk’s commercialization as a sustainable substitute for synthetic fibers, and it can be used in making surgical sutures and comfortable bulletproof vests, according to the study.

Here’s a link to and a citation for the paper,

High-strength and ultra-tough whole spider silk fibers spun from transgenic silkworms by Junpeng Mi, Yizhong Zhou, Sanyuan Ma, Xingping Zhou, Shouying Xu, Yuchen Yang, Yuan Sun, Qingyou Xia, Hongnian Zhu, Suyang Wang, Luyang Tian, Qing Men. Matter Volume 6, ISSUE 10, P3661-3683, October 04, 2023 DOI: https://doi.org/10.1016/j.matt.2023.08.013 First published online: September 20, 2023

This paper is behind a paywall.

Reusable ‘sponge’ for soaking up marine oil spills—even in northern waters

A May 28, 2024 news item on phys.org announces some new research into sponges, a topic of some interest where oil spill cleanups are concerned,

Oil spills, if not cleaned up quickly and effectively, can cause lasting damage to marine and coastal environments. That’s why a team of North American researchers are developing a new sponge-like material that is not only effective at grabbing and holding oil on its surface (adsorption), but can be reused again and again—even in icy Canadian waters….

A May 27, 2024 Canadian Light Source (CLS) news release (also received via email) by Rowan Hollinger provides some details, Note: CNF can be cellulose nanofibers, cellulose nanofibrils, or, it’s sometimes called, nanofibrillated cellulose (NFC) (see Nanocellulose Wikipedia entry),,

The special material – called CNF-SP aerogel — combines a biodegradable cellulose-based material with a substance called spiropyran, a light-sensitive material. Spiropyran has a unique ‘switchable’ property that allows the aerogel to go between being oil-sorbent and oil-repellent, just like a kitchen sponge that can be used to soak up and squeeze out water.

“Once spiropyran has been added to the aerogel, after each usage we just switch the light condition,” explains Dr. Baiyu Helen Zhang, professor and Canada Research Chair at Memorial University, Newfoundland. “We used the aerogel as an oil sorbent under visible light. After oil adsorption, we switched the light condition to UV light. This switch helped the sponge to release the oil.”

And the material continues soaking up and releasing oil, even when the water temperature drops, according to Dr. Xiujuan Chen, an assistant professor at University of Texas – Arlington.

“We found that when we tested the oil sorbent’s performance under different kinds of environmental conditions, it had a very good performance in a cold environment. This is quite useful for cold winter seasons, particularly for Canada.”

The researchers used the CLS’s Mid-IR beamline to examine the characteristics of the aerogel before and after exposing it to visible and UV light. From here, the researchers are looking to scale up their research with large pilot studies and even testing the material in the field.

“The CLS has very unique infrastructure that supports students and researchers like us to conduct many kinds of very exciting research and to contribute to scientific knowledge and engineering applications,” says Zhang.

Here’s a link to and a citation for the paper,

Development of a spiropyran-assisted cellulose aerogel with switchable wettability as oil sorbent for oil spill cleanup by Hongjie Wang, Xiujuan Chen, Bing Chen, Yuming Zhao, Baiyu Zhang. Science of The Total Environment Volume 923, 1 May 2024, 171451 DOI: https://doi.org/10.1016/j.scitotenv.2024.171451 Available online: 2 March 2024 Version of Record: 8 March 2024

This paper is behind a paywall.

The CLS has made this video of the researchers available,

For the curious, I have many posts about sponges and, in particular, sponges for use in environmental cleanups.

A biochemical means of protecting passwords and anti-counterfeiting solution for art and other precious goods

I guess you could say my passwords are as precious to me as a piece.of art is to some people.

DNA can be used to confirm the authenticity of valuable art prints. (AI-​generated image: ETH Zurich)

An April 8, 2024 ETH Zurich press release (also on EurekAlert) by Fabio Bergamin features an approach that could make passwords secure from quantum computers, Note: A link has been removed,

Security experts fear Q-​Day, the day when quantum computers become so powerful that they can crack today’s passwords. Some experts estimate that this day will come within the next ten years. Password checks are based on cryptographic one-​way functions, which calculate an output value from an input value. This makes it possible to check the validity of a password without transmitting the password itself: the one-​way function converts the password into an output value that can then be used to check its validity in, say, online banking. What makes one-​way functions special is that it’s impossible to use their output value to deduce the input value – in other words, the password. At least not with today’s resources. However, future quantum computers could make this kind of inverse calculation easier.

Researchers at ETH Zurich have now presented a cryptographic one-​way function that works differently from today’s and will also be secure in the future. Rather than processing the data using arithmetic operations, it is stored as a sequence of nucleotides – the chemical building blocks of DNA.

Based on true randomness

“Our system is based on true randomness. The input and output values are physically linked, and it’s only possible to get from the input value to the output value, not the other way round,” explains Robert Grass, a professor in the Department of Chemistry and Applied Biosciences. “Since it’s a physical system and not a digital one, it can’t be decoded by an algorithm, not even by one that runs on a quantum computer,” adds Anne Lüscher, a doctoral student in Grass’s group. She is the lead author of the paper, which was published in the journal Nature Communications.

The researchers’ new system can serve as a counterfeit-​proof way of certifying the authenticity of valuable objects such as works of art. The technology could also be used to trace raw materials and industrial products.

How it works

The new biochemical one-​way function is based on a pool of one hundred million different DNA molecules. Each of the molecules contains two segments featuring a random sequence of nucleotides: one segment for the input value and one for the output value. There are several hundred identical copies of each of these DNA molecules in the pool, and the pool can also be divided into several pools; these are identical because they contain the same random DNA molecules. The pools can be located in different places, or they can be built into objects.

Anyone in possession of this DNA pool holds the security system’s lock. The polymerase chain reaction (PCR) can be used to test a key, or input value, which takes the form of a short sequence of nucleotides. During the PCR, this key searches the pool of hundreds of millions of DNA molecules for the molecule with the matching input value, and the PCR then amplifies the output value located on the same molecule. DNA sequencing is used to make the output value readable.

At first glance, the principle seems complicated. “However, producing DNA molecules with built-​in randomness is cheap and easy,” Grass says. The production costs for a DNA pool that can be divided up in this way are less than 1 Swiss franc. Using DNA sequencing to read out the output value is more time-​consuming and expensive, but many biology laboratories already possess the necessary equipment.

Securing valuable goods and supply chains

ETH Zurich has applied for a patent on this new technology. The researchers now want to optimise and refine it to bring it to market. Because using the method calls for specialised laboratory infrastructure, the scientists think the most likely application for this form of password verification is currently for highly sensitive goods or for access to buildings with restricted access. This technology won’t be an option for the broader public to check passwords until DNA sequencing in particular becomes easier.

A little more thought has already gone into the idea of using the technology for the forgery-​proof certification of works of art. For instance, if there are ten copies of a picture, the artist can mark them all with the DNA pool – perhaps by mixing the DNA into the paint, spraying it onto the picture or applying it to a specific spot.

If several owners later wish to have the authenticity of these artworks confirmed, they can get together, agree on a key (i.e. an input value) and carry out the DNA test. All the copies for which the test produces the same output value will have been proven genuine. The new technology could also be used to link crypto-​assets such as NFTs, which exist only in the digital world, to an object and thus to the physical world.

Furthermore, it would support counterfeit-​proof tracking along supply chains of industrial goods or raw materials. “The aviation industry, for example, has to be able to provide complete proof that it uses only original components. Our technology can guarantee traceability,” Grass says. In addition, the method could be used to label the authenticity of original medicines or cosmetics.

Here’s a link to and a citation for the paper,

Chemical unclonable functions based on operable random DNA pools by Anne M. Luescher, Andreas L. Gimpel, Wendelin J. Stark, Reinhard Heckel & Robert N. Grass. Nature Communications volume 15, Article number: 2955 (2024) DOI: https://doi.org/10.1038/s41467-024-47187-7 Published: 05 April 2024

This paper is open access.

Aerogels that are 3D printed from nanocellulose

The one on the far right looks a bit like a frog (to me),

Caption: Complexity and lightness: Empa researchers have developed a 3D printing process for biodegradable cellulose aerogel. Credit: Empa

An April 4, 2024 Swiss Federal Laboratories for Materials Science and Technology (EMPA) press release (also on EurekAlert) describes some interesting possibilities for nanocellulose,

At first glance, biodegradable materials, inks for 3D printing and aerogels don’t seem to have much in common. All three have great potential for the future, however: “green” materials do not pollute the environment, 3D printing can produce complex structures without waste, and ultra-light aerogels are excellent heat insulators. Empa researchers have now succeeded in combining all these advantages in a single material. And their cellulose-based, 3D-printable aerogel can do even more.

The miracle material was created under the leadership of Deeptanshu Sivaraman, Wim Malfait and Shanyu Zhao from Empa’s Building Energy Materials and Components laboratory, in collaboration with the Cellulose & Wood Materials and Advanced Analytical Technologies laboratories as well as the Center for X-ray Analytics. Together with other researchers, Zhao and Malfait had already developed a process for printing silica aerogels in 2020. No trivial task: Silica aerogels are foam-like materials, highly open porous and brittle. Before the Empa development, shaping them into complex forms had been pretty much impossible. “It was the logical next step to apply our printing technology to mechanically more robust bio-based aerogels,” says Zhao.

The researchers chose the most common biopolymer on Earth as their starting material: cellulose. Various nanoparticles can be obtained from this plant-based material using simple processing steps. Doctoral student Deeptanshu Sivaraman used two types of such nanoparticles – cellulose nanocrystals and cellulose nanofibers – to produce the “ink” for printing the bio-aerogel.

Over 80 percent water

The flow characteristics of the ink are crucial in 3D printing: Tt must be viscous enough in order to hold a three-dimensional shape before solidification. At the same time, however, it should liquefy under pressure so that it can flow through the nozzle. With the combination of nanocrystals and nanofibers, Sivaraman succeeded in doing just that: The long nanofibers give the ink a high viscosity, while the rather short crystals ensure that it has shear thinning effect so that it flows more easily during extrusion.

In total, the ink contains around twelve percent cellulose – and 88 percent water. “We were able to achieve the required properties with cellulose alone, without any additives or fillers,” says Sivaraman. This is not only good news for the biodegradability of the final aerogel products, but also for its heat-insulating properties. To turn the ink into an aerogel after printing, the researchers replace the pore solvent water first with ethanol and then with air, all while maintaining shape fidelity. “The less solid matter the ink contains, the more porous the resulting aerogel,” explains Zhao.

This high porosity and the small size of the pores make all aerogels extremely effective heat insulators. However, the researchers have identified a unique property in the printed cellulose aerogel: It is anisotropic. This means its strength and thermal conductivity are direction-dependent. “The anisotropy is partly due to the orientation of the nanocellulose fibers and partly due to the printing process itself,” says Malfait. This allows the researchers to control in which axis the printed aerogel piece should be particularly stable or particularly insulating. Such precisely crafted insulating components could be used in microelectronics, where heat should only be conducted in a certain direction.

A lot of potential applications in medicine

Although the original research project, which was funded by the Swiss National Science Foundation (SNSF), was primarily interested in thermal insulation, the researchers quickly saw another area of application for their printable bio-aerogel: medicine. As it consists of pure cellulose, the new aerogel is biocompatible with living tissues and cells. Its porous structure is able to absorb drugs and then release them into the body over a long period of time. And 3D printing offers the possibility of producing precise shapes that could, for instance, serve as scaffolds for cell growth or as implants.

A particular advantage is that the printed aerogel can be rehydrated and re-dried several times after the initial drying process without losing its shape or porous structure. In practical applications, this would make the material easier to handle: It could be stored and transported in dry form and only be soaked in water shortly before use. When dry, it is not only light and convenient to handle, but also less susceptible to bacteria – and does not have to be elaborately protected from drying out. “If you want to add active ingredients to the aerogel, this can be done in the final rehydration step immediately before use,” says Sivaraman. “Then you don’t run the risk of the medication losing its effectiveness over time or if it is stored incorrectly.”

The researchers are also working on drug delivery from aerogels in a follow-up project – with less focus on 3D printing for now. Shanyu Zhao is collaborating with researchers from Germany and Spain on aerogels made from other biopolymers, such as alginate and chitosan, derived from algae and chitin respectively. Meanwhile, Wim Malfait wants to further improve the thermal insulation of cellulose aerogels. And Deeptanshu Sivaraman has completed his doctorate and has since joined the Empa spin-off Siloxene AG, which creates new hybrid molecules based on silicon.

Fascinating work and here’s a link to and a citation for the paper,

Additive Manufacturing of Nanocellulose Aerogels with Structure-Oriented Thermal, Mechanical, and Biological Properties by Deeptanshu Sivaraman, Yannick Nagel, Gilberto Siqueira, Parth Chansoria, Jonathan Avaro, Antonia Neels, Gustav Nyström, Zhaoxia Sun, Jing Wang, Zhengyuan Pan, Ana Iglesias-Mejuto, Inés Ardao, Carlos A. García-González, Mengmeng Li, Tingting Wu, Marco Lattuada, Wim J. Malfait, Shanyu Zhao. Advanced Science DOI: https://doi.org/10.1002/advs.202307921 First published: 13 March 2024

This paper is open access.

You can find Siloxene AG here.

Could this discovery end global amphibian pandemic?

Caption: Panamanian golden frog is nearing extinction. Credit: Brian Gratwicke/U.S. Fish & Wildlife Service

An April 3, 2024 University of California at Riverside (also on EurekAlert) by Jules Bernstein describes the possibility of using a virus to infect a fungus that kills frogs worldwide, Note: A link has been removed,

A fungus devastating frogs and toads on nearly every continent may have an Achilles heel. Scientists have discovered a virus that infects the fungus, and that could be engineered to save the amphibians.

The fungus, Batrachochytrium dendrobatidis or Bd, ravages the skin of frogs and toads, and eventually causes heart failure. To date it has contributed to the decline of over 500 amphibian species, and 90 possible extinctions including yellow-legged mountain frogs in the Sierras and the Panamanian golden frog. 

A new paper in the journal Current Biology documents the discovery of a virus that infects Bd, and which could be engineered to control the fungal disease.

The UC Riverside researchers who found the virus are excited about the implications of their discovery. In addition to helping them learn about how fungal pathogens rise and spread, it offers the hope of ending what they call a global amphibian pandemic. 

“Frogs control bad insects, crop pests, and mosquitoes. If their populations all over the world collapse, it could be devastating,” said UCR microbiology doctoral student and paper author Mark Yacoub. 

“They’re also the canary in the coal mine of climate change. As temperatures get warmer, UV light gets stronger, and water quality gets worse, frogs respond to that. If they get wiped out, we lose an important environmental signal,” Yacoub said. 

Bd was not prevalent before the late 1990s, but then, “all of a sudden frogs started dying,” Yacoub said.

When they found the Bd-infecting virus, Yacoub and UCR microbiology professor Jason Stajich had been working on the population genetics of Bd, hoping to gain a better understanding about where it came from and how it is mutating. 

“We wanted to see how different strains of fungus differ in places like Africa, Brazil, and the U.S., just like people study different strains of COVID-19,” Stajich said. To do this, the researchers used DNA sequencing technology. As they examined the data, they noticed some sequences that did not match the DNA of the fungus. 

“We realized these extra sequences, when put together, had the hallmarks of a viral genome,” Stajich said. 

Previously, researchers have looked for Bd viruses but did not find them. The fungus itself is hard to study because complex procedures are required to keep it alive in a laboratory. 

“It is also a hard fungus to keep track of because they have a life stage where they’re motile, they have a flagellus, which resembles a sperm tail, and they swim around,” Stajich said. 

Additionally, the virus that infects Bd was hard to find because most known viruses that infect fungi, called mycoviruses, are RNA viruses. However, this virus is a single-stranded DNA virus. By studying the DNA, the researchers could see the virus stuck in the genome of the fungus. 

It appears that only some strains of the fungus have the virus in their genome. But the infected ones seem to behave differently than the ones that don’t. “When these strains possess the virus they produce fewer spores, so it spreads more slowly. But they also might become more virulent, killing frogs faster,” Stajich said. 

Right now, the virus is essentially trapped inside the fungal genome. The researchers would eventually like to clone the virus and see if a manually infected strain of Bd also produces fewer spores.

“Because some strains of the fungus are infected and some are not, this underscores the importance of studying multiple strains of a fungal species,” Yacoub said. 

Moving forward, the researchers are looking for insights into the ways that the virus operates. “We don’t know how the virus infects the fungus, how it gets into the cells,” Yacoub said. “If we’re going to engineer the virus to help amphibians, we need answers to questions like these.”

In some places, it appears there are a few amphibian species acquiring resistance to Bd. “Like with COVID, there is a slow buildup of immunity. We are hoping to assist nature in taking its course,” Yacoub said. 

Here’s a link to and a citation for the paper,

An endogenous DNA virus in an amphibian-killing fungus associated with pathogen genotype and virulence by Rebecca A. Clemons, Mark N. Yacoub, Evelyn Faust, L. Felipe Toledo, Thomas S. Jenkinson, Tamilie Carvalho, D. Rabern Simmons, Erik Kalinka, Lillian K. Fritz-Laylin, Timothy Y. James, Jason E. Stajich. Current Biology Volume 34, ISSUE 7, P1469-1478.e6, April 08, 2024 DOI: https://doi.org/10.1016/j.cub.2024.02.062 Published online: March 14, 2024

This paper is open access.

Pulp and paper waste for scrubbing carbon from emissions

This first news release is a little short but the next one is one of the shortest I can recall seeing. First, a February 1, 2024 Canadian Light Source (CLS) news release by Victoria Martinez,

Researchers at McGill University have come up with an innovative approach to improve the energy efficiency of carbon conversion, using waste material from pulp and paper production. The technique they’ve pioneered using the Canadian Light Source at the University of Saskatchewan not only reduces the energy required to convert carbon into useful products, but also reduces overall waste in the environment.

“This is a new field,” says Roger Lin, a graduate student in chemical engineering “We are one of the first groups to combine biomass recycling or utilization with CO2 capture.” The research team, from McGill’s Electrocatalysis Lab, published their findings in the journal RSC [Royal Society of Chemistry] Sustainability.

Capturing carbon emissions is one of the most exciting emerging tools to fight climate change. The biggest challenge is figuring out what to do with the carbon once the emissions have been removed, especially since capturing CO2 can be expensive. The next hurdle is that transforming CO2 into useful products takes energy. Researchers want to make the conversion process as efficient and profitable as possible.

“For these reactions, it really matters that we target energy efficiency,” says Amirhossein Farzi, a PhD student in chemical engineering at McGill. “The highest burden on the profitability of these reactions and these processes is usually how energy efficient they are.”

Farzi, Lin, and their research team focused their efforts on changing out one of the most energy-intensive parts of the carbon conversion process.

Because the approach is so new, there are many questions to answer about how to get the purest outputs and best efficiency. The team used CLS beamlines to observe chemical reactions in real-time, mimicking industrial processes as closely as possible.

The researchers hope to expand the range of products that can be made with CO2, and help develop a truly green technology.

“If we use a renewable energy source like hydro, wind, or solar …then in the end, we have really a carbon negative process,” says Lin.

Then, there was a March 27, 2024 McGill University news release (also on EurekAlert but published April 8, 2024), which is more succinct,

Researchers at McGill University have come up with an innovative approach to improve the energy efficiency of carbon conversion, using waste material from pulp and paper production. The technique they’ve pioneered using the Canadian Light Source at the University of Saskatchewan not only reduces the energy required to convert carbon into useful products, but also reduces overall waste in the environment.

“We are one of the first groups to combine biomass recycling or utilization with CO2 capture,” said Ali Seifitokaldani, Assistant Professor in the Department of Chemical Engineering and Canada Research Chair (Tier II) in Electrocatalysis for Renewable Energy Production and Conversion. The research team, from McGill’s Electrocatalysis Lab, published their findings in the journal RSC Sustainability.

Capturing carbon emissions is one of the most exciting emerging tools to fight climate change. The biggest challenge is figuring out what to do with the carbon once the emissions have been removed, especially since capturing CO2 can be expensive. The next hurdle is that transforming CO2 into useful products takes energy. Researchers want to make the conversion process as efficient and profitable as possible.

Here’s a link to and a citation for the paper,

Efficient integration of carbon dioxide reduction and 5-hydroxymethylfurfural oxidation at high current density by Roger Lin, Haoyan Yang, Hanyu Zheng, Mahdi Salehi, Amirhossein Farzi, Poojan Patel, Xiao Wang, Jiaxun Guo, Kefang Liu, Zhengyuan Gao, Xiaojia Li, Ali Seifitokaldani. RSC Sustainability, 2024; 2 (2): 445 DOI: 10.1039/D3SU00379E First published online: 13 Dec 2023

This paper is open access.

H/t April 8, 2024 news item on ScienceDaily