An article by Annie Darling focused on watchmaking and the influence an emerging technology (nanotechnology) can have on this well established field was making the rounds not too long ago (March 6, 2023 on SCMP and March 7, 2023 on Luxury Launches), Note: Links have been removed,
Ever since spring-powered clocks were developed in 15th century Europe, watchmakers have strived to advance the science behind haute horlogerie. First, the mainspring was brainstormed as a mechanism for powering a clock. This apparatus stopped the cracking and weakening of a timepiece’s movement so it could withstand numerous cycles.
Next came the balance wheel, which ensures that movements are able to keep regular time, invented in the mid-17th century by Dutch mathematician and all-round know-it-all Christiaan Huygens. And, of course, any collector worth their salt knows about Abraham-Louis Breguet’s tourbillon that rotates a timepiece’s movement to counter the negative effect of Earth’s gravity.
A lot has changed in the years since, with improved materials and methods allowing for increased miniaturisation, precision and reliability. Now, another wave of innovation is breaking over the field of watchmaking: nanotechnology, the study and manipulation of matter on a near-atomic scale to produce novel structures and materials.
Now watchmakers are starting to take notice, with Hermès incorporating nanotechnology into its novelties for 2023. The Crepuscule – “dusk” in French – is the new iteration of the brand’s emblematic Cape Cod watch. Designed by artist Thanh Phong Lê, the dial features a pensive piece of graphic art depicting a setting sun reflected in water.
One of Switzerland’s leading silicon experts, the Swiss Center for Electronics and Microtechnology, was commissioned to complete the dial, shaped using a silicon wafer just 0.5mm thick. To reach the intensity of colour requested by the maison, a nanotechnology procedure called photolithography was used to transfer Phong Lê’s motif onto the silicon, which was then coated in yellow gold.
Tag Heuer is also experimenting with nanotechnology and has patented a carbon composite hairspring, which comprises of rolled-up sheets [carbon nanotubes; CNTs], each just a single layer of carbon atoms. The hairspring is attached to a watch’s balance wheel to help mechanical timepieces keep accurate time. “Our hairspring is at the very heart of our movements,” says Emmanuel Dupas, director of the Tag Heuer Institute. “We developed our own hairspring based on a carbon nanotube scaffold, which is filled with amorphous carbon. Carbon nanotubes have extremely narrow diameters but can be very long.”
it’s a good article if watchmaking and/or luxury products and/or applied nanotechology interests you. Whichever site you choose (March 6, 2023 on SCMP or March 7, 2023 on Luxury Launches), you’ll find more embedded images of watches from different companies.
This is, however, the first time I’ve seen CNTs used for ‘stab-resistant’ clothing. From an April 19, 2023 news item on ScienceDaily,
Fabrics that resist knife cuts can help prevent injuries and save lives. But a sharp enough knife or a very forceful jab can get through some of these materials. Now, researchers report in ACS Applied Nano Materials that carbon nanotubes and polyacrylate strengthen conventional aramid to produce lightweight, soft fabrics that provide better protection. Applications include anti-stabbing clothing, helmets and insoles, as well as cut-resistant packaging.
Soft body armor is typically made from aramid, ultra-high-molecular-weight polyethylene, or carbon and glass fabrics. Their puncture resistance depends, in part, on the friction between yarn fibers within these materials. Up to a point, greater friction means greater protection. Manufacturers can boost friction by roughening the fiber surfaces, but that requires a complicated process, and product yield is low. Alternatively, the bonding force between yarns can be enhanced by adding another component, such as a sheer thickening fluid (STF) or a polyurethane (PU) coating. But these composite fabrics can’t simultaneously satisfy the requirements for thinness, flexibility and light weight. Ting-Ting Li, Xing-xiang Zhang and colleagues wanted to find another way to improve performance while satisfying these criteria.
The researchers tested a polyacrylate emulsion (PAE), STF and PU as coatings on aramid fabric. In simulated stabbing tests, aramid fabric coated with PAE outperformed the uncoated material used by itself or in combination with STF or PU. Carbon nanotubes are known to make composites tougher, and adding them to aramid/PAE further improved impact resistance. The team says that’s because the nanotubes created bridges between the fibers, thereby increasing friction. The nanotubes also formed a thin, protective network that dispersed stress away from the point of impact and helped prevent fiber disintegration. The new lightweight, flexible, puncture-resistant composite fabric could be useful in military and civilian applications, according to the researchers.
Like a giraffe stretching for leaves on a tall tree, making carbon nanotubes reach for food as they grow may lead to a long-sought breakthrough.
Materials theorists Boris Yakobson and Ksenia Bets at Rice University’s George R. Brown School of Engineering show how putting constraints on growing nanotubes could facilitate a “holy grail” of growing batches with a single desired chirality.
Their paper in Science Advances describes a strategy by which constraining the carbon feedstock in a furnace would help control the “kite” growth of nanotubes. In this method, the nanotube begins to form at the metal catalyst on a substrate, but lifts the catalyst as it grows, resembling a kite on a string.
Carbon nanotube walls are basically graphene, its hexagonal lattice of atoms rolled into a tube. Chirality refers to how the hexagons are angled within the lattice, between 0 and 30 degrees. That determines whether the nanotubes are metallic or semiconductors. The ability to grow long nanotubes in a single chirality could, for instance, enable the manufacture of highly conductive nanotube fibers or semiconductor channels of transistors.
Normally, nanotubes grow in random fashion with single and multiple walls and various chiralities. That’s fine for some applications, but many need “purified” batches that require centrifugation or other costly strategies to separate the nanotubes.
The researchers suggested hot carbon feedstock gas fed through moving nozzles could effectively lead nanotubes to grow for as long as the catalyst remains active. Because tubes with different chiralities grow at different speeds, they could then be separated by length, and slower-growing types could be completely eliminated.
One additional step that involves etching away some of the nanotubes could then allow specific chiralities to be harvested, they determined.
The lab’s work to define the mechanisms of nanotube growth led them to think about whether the speed of growth as a function of individual tubes’ chirality could be useful. The angle of “kinks” in the growing nanotubes’ edges determines how energetically amenable they are to adding new carbon atoms.
“The catalyst particles are moving as the nanotubes grow, and that’s principally important,” said lead author Bets, a researcher in Yakobson’s group. “If your feedstock keeps moving away, you get a moving window where you’re feeding some tubes and not the others.”
The paper’s reference to Lamarck giraffes — a 19th-century theory of how they evolved such long necks — isn’t entirely out of left field, Bets said.
“It works as a metaphor because you move your ‘leaves’ away and the tubes that can reach it continue growing fast, and those that cannot just die out,” she said. “Eventually, all the nanotubes that are just a tiny bit slow will ‘die.’”
Speed is only part of the strategy. In fact, they suggest nanotubes that are a little slower should be the target to assure a harvest of single chiralities.
Because nanotubes of different chiralities grow at their own rates, a batch would likely exhibit tiers. Chemically etching the longest nanotubes would degrade them, preserving the next level of tubes. Restoring the feedstock could then allow the second-tier nanotubes to continue growing until they are ready to be culled, Bets said.
“There are three or four laboratory studies that show nanotube growth can be reversed, and we also know it can be restarted after etching,” she said. “So all the parts of our idea already exist, even if some of them are tricky. Close to equilibrium, you will have the same proportionality between growth and etching speeds for the same tubes. If it’s all nice and clean, then you can absolutely, precisely pick the tubes you target.”
The Yakobson lab won’t make them, as it focuses on theory, not experimentation. But other labs have turned past Rice theories into products like boron buckyballs.
“I’m pretty sure every single one of our reviewers were experimentalists, and they didn’t see any contradictions to it working,” Bets said. “Their only complaint, of course, was that they would like experimental results right now, but that’s not what we do.”
She hopes more than a few labs will pick up the challenge. “In terms of science, it’s usually more beneficial to give ideas to the crowd,” Bets said. “That way, those who have interest can do it in 100 different variations and see which one works. One guy trying it might take 100 years.”
Yakobson added, “We don’t want to be that ‘guy.’ We don’t have that much time.”
It’s always interesting to come across different news releases announcing the same research. In this case I have two news releases, one from the US National Science Foundation (NSF) and one from the University of Arizona. Let’s start with the July 19, 2022 news item on phys.org (originated by the US NSF),
Astronomers at the University of Arizona have developed a theory to explain the presence of the largest molecules known to exist in interstellar gas.
The team simulated the environment of dying stars and observed the formation of buckyballs (carbon atoms linked to three other carbon atoms by covalent bonds) and carbon nanotubes (rolled up sheets of single-layer carbon atoms). The findings indicate that buckyballs and carbon nanotubes can form when silicon carbide dust — known to be proximate to dying stars — releases carbon in reaction to intense heat, shockwaves and high energy particles.
“We know from infrared observations that buckyballs populate the interstellar medium,” said Jacob Bernal, who led the research. “The big problem has been explaining how these massive, complex carbon molecules could possibly form in an environment saturated with hydrogen, which is what you typically have around a dying star.”
Rearranging the structure of graphene (a sheet of single-layer carbon atoms) could create buckyballs and nanotubes. Building on that, the team heated silicon carbide samples to temperatures that would mimic the aura of a dying star and observed the formation of nanotubes.
“We were surprised we could make these extraordinary structures,” Bernal said. “Chemically, our nanotubes are very simple, but they are extremely beautiful.”
Buckyballs are the largest molecules currently known to occur in interstellar space. It is now known that buckyballs containing 60 to 70 carbon atoms are common.
“We know the raw material is there, and we know the conditions are very close to what you’d see near the envelope of a dying star,” study co-author Lucy Ziurys said. “Shock waves pass through the envelope, and the temperature and pressure conditions have been shown to exist in space. We also see buckyballs in planetary nebulae — in other words, we see the beginning and the end products you would expect in our experiments.”
In the mid-1980s, the discovery of complex carbon molecules drifting through the interstellar medium garnered significant attention, with possibly the most famous examples being Buckminsterfullerene, or “buckyballs” – spheres consisting of 60 or 70 carbon atoms. However, scientists have struggled to understand how these molecules can form in space.
In a paper accepted for publication in the Journal of Physical Chemistry A, researchers from the University of Arizona suggest a surprisingly simple explanation. After exposing silicon carbide – a common ingredient of dust grains in planetary nebulae – to conditions similar to those found around dying stars, the researchers observed the spontaneous formation of carbon nanotubes, which are highly structured rod-like molecules consisting of multiple layers of carbon sheets. The findings were presented on June 16  at the 240th Meeting of the American Astronomical Society in Pasadena, California.
Led by UArizona researcher Jacob Bernal, the work builds on research published in 2019, when the group showed that they could create buckyballs using the same experimental setup. The work suggests that buckyballs and carbon nanotubes could form when the silicon carbide dust made by dying stars is hit by high temperatures, shock waves and high-energy particles, leaching silicon from the surface and leaving carbon behind.
The findings support the idea that dying stars may seed the interstellar medium with nanotubes and possibly other complex carbon molecules. The results have implications for astrobiology, as they provide a mechanism for concentrating carbon that could then be transported to planetary systems.
“We know from infrared observations that buckyballs populate the interstellar medium,” said Bernal, a postdoctoral research associate in the UArizona Lunar and Planetary Laboratory. “The big problem has been explaining how these massive, complex carbon molecules could possibly form in an environment saturated with hydrogen, which is what you typically have around a dying star.”
The formation of carbon-rich molecules, let alone species containing purely carbon, in the presence of hydrogen is virtually impossible due to thermodynamic laws. The new study findings offer an alternative scenario: Instead of assembling individual carbon atoms, buckyballs and nanotubes could result from simply rearranging the structure of graphene – single-layered carbon sheets that are known to form on the surface of heated silicon carbide grains.
This is exactly what Bernal and his co-authors observed when they heated commercially available silicon carbide samples to temperatures occurring in dying or dead stars and imaged them. As the temperature approached 1,050 degreesCelsius, small hemispherical structures with the approximate size of about 1 nanometer were observed at the grain surface. Within minutes of continued heating, the spherical buds began to grow into rod-like structures, containing several graphene layers with curvature and dimensions indicating a tubular form. The resulting nanotubules ranged from about 3 to 4 nanometers in length and width, larger than buckyballs. The largest imaged specimens were comprised of more than four layers of graphitic carbon. During the heating experiment, the tubes were observed to wiggle before budding off the surface and getting sucked into the vacuum surrounding the sample.
“We were surprised we could make these extraordinary structures,” Bernal said. “Chemically, our nanotubes are very simple, but they are extremely beautiful.”
Named after their resemblance to architectural works by Richard Buckminster Fuller, fullerenes are the largest molecules currently known to occur in interstellar space, which for decades was believed to be devoid of any molecules containing more than a few atoms, 10 at most. It is now well established that the fullerenes C60 and C70, which contain 60 or 70 carbon atoms, respectively, are common ingredients of the interstellar medium.
One of the first of its kind in the world, the transmission electron microscope housed at the Kuiper Materials Imaging and Characterization Facility at UArizona is uniquely suited to simulate the planetary nebula environment. Its 200,000-volt electron beam can probe matter down to 78 picometers – the distance of two hydrogen atoms in a water molecule – making it possible to see individual atoms. The instrument operates in a vacuum closely resembling the pressure – or lack thereof – thought to exist in circumstellar environments.
While a spherical C60 molecule measures 0.7 nanometers in diameter, the nanotube structures formed in this experiment measured several times the size of C60, easily exceeding 1,000 carbon atoms. The study authors are confident their experiments accurately replicated the temperature and density conditions that would be expected in a planetary nebula, said co-author Lucy Ziurys, a UArizona Regents Professor of Astronomy, Chemistry and Biochemistry.
“We know the raw material is there, and we know the conditions are very close to what you’d see near the envelope of a dying star,” she said. “There are shock waves that pass through the envelope, so the temperature and pressure conditions have been shown to exist in space. We also see buckyballs in these planetary nebulae – in other words, we see the beginning and the end products you would expect in our experiments.”
These experimental simulations suggest that carbon nanotubes, along with the smaller fullerenes, are subsequently injected into the interstellar medium. Carbon nanotubes are known to have high stability against radiation, and fullerenes are able to survive for millions of years when adequately shielded from high-energy cosmic radiation. Carbon-rich meteorites, such as carbonaceous chondrites, could contain these structures as well, the researchers propose.
According to study co-author Tom Zega, a professor in the UArizona Lunar and Planetary Lab, the challenge is finding nanotubes in these meteorites, because of the very small grain sizes and because the meteorites are a complex mix of organic and inorganic materials, some with sizes similar to those of nanotubes.
“Nonetheless, our experiments suggest that such materials could have formed in interstellar space,” Zega said. “If they survived the journey to our local part of the galaxy where our solar system formed some 4.5 billion years ago, then they could be preserved inside of the material that was left over.”
Zega said a prime example of such leftover material is Bennu, a carbonaceous near-Earth asteroid from which NASA’s UArizona-led OSIRIS-REx mission scooped up a sample in October 2020. Scientists are eagerly awaiting the arrival of that sample, scheduled for 2023.
“Asteroid Bennu could have preserved these materials, so it is possible we may find nanotubes in them,” Zega said.
it seems Australian researchers are working hard to find ways of removing microplastics from water. I have two items, first, a November 29, 2022 news item on Nanowerk announces some of the latest work,
Researchers at RMIT University have found an innovative way to rapidly remove hazardous microplastics from water using magnets.
Lead researcher Professor Nicky Eshtiaghi said existing methods could take days to remove microplastics from water, while their cheap and sustainable invention achieves better results in just one hour.
The team says they have developed adsorbents, in the form of a powder, that remove microplastics 1,000 times smaller than those currently detectable by existing wastewater treatment plants.
The researchers have successfully tested the adsorbents in the lab, and they plan to engage with industry to further develop the innovation to remove microplastics from waterways.
“The nano-pillar structure we’ve engineered to remove this pollution, which is impossible to see but very harmful to the environment, is recycled from waste and can be used multiple times,” said Eshtiaghi from RMIT’s School of Environmental and Chemical Engineering.
“This is a big win for the environment and the circular economy.”
How does this innovation work?
The researchers have developed an adsorbent using nanomaterials that they can mix into water to attract microplastics and dissolved pollutants.
Muhammad Haris, the first author and PhD candidate from RMIT’s School of Environmental and Chemical Engineering, said the nanomaterials contained iron, which enabled the team to use magnets to easily separate the microplastics and pollutants from the water.
“This whole process takes one hour, compared to other inventions taking days,” he said.
Co-lead researcher Dr Nasir Mahmood said the nano-pillar structured material was designed to attract microplastics without creating any secondary pollutants or carbon footprints.
“The adsorbent is prepared with special surface properties so that it can effectively and simultaneously remove both microplastics and dissolved pollutants from water,” said Mahmood from Applied Chemistry and Environmental Science at RMIT.
“Microplastics smaller than 5 millimetres, which can take up to 450 years to degrade, are not detectable and removable through conventional treatment systems, resulting in millions of tonnes being released into the sea every year. This is not only harmful for aquatic life, but also has significant negative impacts on human health.”
The team received scientific and technical support from the Microscopy and Microanalysis Facility and the Micro Nano Research Facility, part of RMIT’s newly expanded Advanced Manufacturing Precinct, to complete their research.
What are the next steps?
Developing a cost-effective way to overcome these signficant challenges posed by microplastics was critical, Eshtiaghi said.
“Our powder additive can remove microplastics that are 1,000 times smaller than those that are currently detectable by existing wastewater treatment plants,” she said.
“We are looking for industrial collaborators to take our invention to the next steps, where we will be looking at its application in wastewater treatment plants.”
Eshtiaghi and her colleagues have worked with various water utilities across Australia, including with Melbourne Water and Water Corporation in Perth on a recent Australian Research Council Linkage project to optimise sludge pumping systems.
Plastic waste that finds its way into oceans and rivers poses a global environmental threat with damaging health consequences for animals, humans, and ecosystems. Now, using tiny coil-shaped carbon-based magnets, researchers in Australia have developed a new approach to purging water sources of the microplastics that pollute them without harming nearby microorganisms. Their work appears July 31 in the journal Matter.
“Microplastics adsorb organic and metal contaminants as they travel through water and release these hazardous substances into aquatic organisms when eaten, causing them to accumulate all the way up the food chain” says senior author Shaobin Wang, a professor of chemical engineering at the University of Adelaide (Australia). “Carbon nanosprings are strong and stable enough to break these microplastics down into compounds that do not pose such a threat to the marine ecosystem.”
Although often invisible to the naked eye, microplastics are ubiquitous pollutants. Some, such as the exfoliating beads found in popular cosmetics, are simply too small to be filtered out during industrial water treatment. Others are produced indirectly, when larger debris like soda bottles or tires weather amid sun and sand.
To decompose the microplastics, the researchers had to generate short-lived chemicals called reactive oxygen species, which trigger chain reactions that chop the various long molecules that make up microplastics into tiny and harmless segments that dissolve in water. However, reactive oxygen species are often produced using heavy metals such as iron or cobalt, which are dangerous pollutants in their own right and thus unsuitable in an environmental context.
To get around this challenge, the researchers found a greener solution in the form of carbon nanotubes laced with nitrogen to help boost generation of reactive oxygen species. Shaped like springs, the carbon nanotube catalysts removed a significant fraction of microplastics in just eight hours while remaining stable themselves in the harsh oxidative conditions needed for microplastics breakdown. The coiled shape increases stability and maximises reactive surface area. As a bonus, by including a small amount of manganese, buried far from the surface of the nanotubes to prevent it from leaching into water, the minute springs became magnetic.
“Having magnetic nanotubes is particularly exciting because this makes it easy to collect them from real wastewater streams for repeated use in environmental remediation,” says Xiaoguang Duan, a chemical engineering research fellow at Adelaide who also co-led the project.
As no two microplastics are chemically quite the same, the researchers’ next steps will center on ensuring that the nanosprings work on microplastics of different compositions, shapes and origins. They also intend to continue to rigorously confirm the non-toxicity of any chemical compounds occurring as intermediates or by-products during microplastics decomposition.
The researchers also say that those intermediates and byproducts could be harnessed as an energy source for microorganisms that the polluting plastics currently plague. “If plastic contaminants can be repurposed as food for algae growth, it will be a triumph for using biotechnology to solve environmental problems in ways that are both green and cost efficient,” Wang says.
I’m glad to see this work and as for which approach might be preferable, I don’t know if there’s a clear winner. The 2022 work removes both microplastics and pollutants in one hour! An impressive feat, which leaves us with microplastics and pollutants to deal with. By contrast , the 2019 work transforms the microplastics into materials that don’t pose harm to the aquatic environment. Great although it takes eight hours. I wish the best for all the researchers working on this microplastics problem.
An April 27, 2022 news item on ScienceDaily announces research into a solution to a vexing problem associated with the production of carbon nanotubes (CNTs),
Carbon nanotubes that are prone to tangle like spaghetti can use a little special sauce to realize their full potential.
Rice University scientists have come up with just the sauce, an acid-based solvent that simplifies carbon nanotube processing in a way that’s easier to scale up for industrial applications.
The Rice lab of Matteo Pasquali reported in Science Advances on its discovery of a unique combination of acids that helps separate nanotubes in a solution and turn them into films, fibers or other materials with excellent electrical and mechanical properties.
The study co-led by graduate alumnus Robert Headrick and graduate student Steven Williams reports the solvent is compatible with conventional manufacturing processes. That should help it find a place in the production of advanced materials for many applications.
An April 22, 2022 Rice University news release (received via email and also published on April 27, 2022 on EurekAlert), which originated the news item, delves further into how the research has environmental benefits and into its technical aspects (Note Links have been removed),
“There’s a growing realization that it’s probably not a good idea to increase the mining of copper and aluminum and nickel,” said Pasquali, Rice’s A.J. Hartsook Professor and a professor of chemical and biomolecular engineering, chemistry and materials science and nanoengineering. He is also director of the Rice-based Carbon Hub, which promotes the development of advanced carbon materials to benefit the environment.
“But there is this giant opportunity to use hydrocarbons as our ore,” he said. “In that light, we need to broaden as much as possible the range in which we can use carbon materials, especially where it can displace metals with a product that can be manufactured sustainably from a feedstock like hydrocarbons.” Pasquali noted these manufacturing processes produce clean hydrogen as well.
“Carbon is plentiful, we control the supply chains and we know how to get it out in an environmentally responsible way,” he said.
A better way to process carbon will help. The solvent is based on methanesulfonic (MSA), p-toluenesulfonic (pToS)and oleum acids that, when combined, are less corrosive than those currently used to process nanotubes in a solution. Separating nanotubes (which researchers refer to as dissolving) is a necessary step before they can be extruded through a needle or other device where shear forces help turn them into familiar fibers or sheets.
Oleum and chlorosulfonic acids have long been used to dissolve nanotubes without modifying their structures, but both are highly corrosive. By combining oleum with two weaker acids, the team developed a broadly applicable process that enables new manufacturing for nanotubes products.
“The oleum surrounds each individual nanotube and gives it a very localized positive charge,” said Headrick, now a research scientist at Shell. “That charge makes them repel each other.”
After detangling, the milder acids further separate the nanotubes. They found MSA is best for fiber spinning and roll-to-roll film production, while pToS, a solid that melts at 40 degrees Celsius (104 degrees Fahrenheit), is particularly useful for 3D printing applications because it allows nanotube solutions to be processed at a moderate temperature and then solidified by cooling.
The researchers used these stable liquid crystalline solutions to make things in both modern and traditional ways, 3D printing carbon nanotube aerogels and silk screen printing patterns onto a variety of surfaces, including glass.
The solutions also enabled roll-to-roll production of transparent films that can be used as electrodes. “Honestly, it was a little surprising how well that worked,” Headrick said. “It came out pretty flawless on the very first try.”
The researchers noted oleum still requires careful handling, but once diluted with the other acids, the solution is much less aggressive to other materials.
“The acids we’re using are so much gentler that you can use them with common plastics,” Headrick said. “That opens the door to a lot of materials processing and printing techniques that are already in place in manufacturing facilities.
“It’s also really important for integrating carbon nanotubes into other devices, depositing them as one step in a device-manufacturing process,” he said.
They reported the less-corrosive solutions did not give off harmful fumes and were easier to clean up after production. MSA and pToS can also be recycled after processing nanotubes, lowering their environmental impact and energy and processing costs.
Williams said the next step is to fine-tune the solvent for applications, and to determine how factors like chirality and size affect nanotube processing. “It’s really important that we have high-quality, clean, large diameter tubes,” he said.
Co-authors of the paper are alumna Lauren Taylor and graduate students Oliver Dewey and Cedric Ginestra of Rice; graduate student Crystal Owens and professors Gareth McKinley and A. John Hart at the Massachusetts Institute of Technology; alumna Lucy Liberman, graduate student Asia Matatyaho Ya’akobi and Yeshayahu Talmon, a professor emeritus of chemical engineering, at the Technion-Israel Institute of Technology, Haifa, Israel; and Benji Maruyama, autonomous materials lead in the Materials and Manufacturing Directorate, Air Force Research Laboratory.
Here’s a link to and a citation for the paper,
Versatile acid solvents for pristine carbon nanotube assembly by Robert J. Headrick, Steven M. Williams, Crystal E. Owens, Lauren W. Taylor, Oliver S. Dewey, Cedric J. Ginestra, Lucy Liberman, Asia Matatyaho Ya’akobi, Yeshayahu Talmon, Benji Maruyama, Gareth H. McKinley, A. John Hart, Matteo Pasquali. Science Advances • 27 Apr 2022 • Vol 8, Issue 17 • DOI: 10.1126/sciadv.abm3285
It is a staple of science fiction to mock sutures as outdated. The technique has, after all, been in use for at least 5,000 years. Surely medicine should have advanced since ancient Egypt. Professor Hossam Haick from the Wolfson Department of Chemical Engineering at the Technion has finally turned science fiction into reality. His lab succeeded in creating a smart sutureless dressing that binds the wound together, wards off infection, and reports on the wound’s condition directly to the doctors’ computers. Their study was published in Advanced Materials.
Current surgical procedures entail the surgeon cutting the human body, doing what needs to be done, and sewing the wound shut – an invasive procedure that damages surrounding healthy tissue. Some sutures degrade by themselves – or should degrade – as the wound heals. Others need to be manually removed. Dressing is then applied over the wound and medical personnel monitor the wound by removing the dressing to allow observation for signs of infection like swelling, redness, and heat. This procedure is painful to the patient, and disruptive to healing, but it is unavoidable. Working with these methods also mean that infection is often discovered late, since it takes time for visible signs to appear, and more time for the inspection to come round and see them. In developed countries, with good sanitation available, about 20% of patients develop infections post-surgery, necessitating additional treatment and extending the time to recovery. The figure and consequences are much worse in developing countries.
How will it work with Prof. Haick’s new dressing?
Prior to beginning a procedure, the dressing – which is very much like a smart band-aid – developed by Prof. Haick’s lab will be applied to the site of the planned incision. The incision will then be made through it. Following the surgery, the two ends of the wound will be brought together, and within three seconds the dressing will bind itself together, holding the wound closed, similarly to sutures. From then, the dressing will be continuously monitoring the wound, tracking the healing process, checking for signs of infection like changes in temperature, pH, and glucose levels, and report to the medical personnel’s smartphones or other devices. The dressing will also itself release antibiotics onto the wound area, preventing infection.
“I was watching a movie on futuristic robotics with my kids late one night,” said Prof. Haick, “and I thought, what if we could really make self-repairing sensors?”
Most people discard their late-night cinema-inspired ideas. Not Prof. Haick, who, the very next day after his Eureka moment, was researching and making plans. The first publication about a self-healing sensor came in 2015 (read more about it on the Technion website here). At that time, the sensor needed almost 24 hours to repair itself. By 2020, sensors were healing in under a minute (read about the study by Muhammad Khatib, a student in Prof. Haick’s lab here), but while it had multiple applications, it was not yet biocompatible, that is, not usable in contact with skin and blood. Creating a polymer that would be both biocompatible and self-healing was the next step, and one that was achieved by postdoctoral fellow Dr. Ning Tang.
The new polymer is structured like a molecular zipper, made from sulfur and nitrogen: the surgeon’s scalpel opens it; then pressed together, it closes and holds fast. Integrated carbon nanotubes provide electric conductivity and the integration of the sensor array. In experiments, wounds closed with the smart dressing healed as fast as those closed with sutures and showed reduced rates of infection.
“It’s a new approach to wound treatment,” said Prof. Haick. “We introduce the advances of the fourth industrial revolution – smart interconnected devices, into the day-to-day treatment of patients.”
Prof. Haick is the head of the Laboratory for Nanomaterial-based Devices (LNBD) and the Dean of Undergraduate Studies at the Technion. Dr. Ning Tang was a postdoctoral fellow in Prof. Haick’s laboratory and conducted this study as part of his fellowship. He has now been appointed an associate professor in Shanghai Jiao Tong University.
I usually like to have three links to a news/press release and in my searches for a third source for this press release, I stumbled onto the technioncanada.org website. They seemed to have scooped everyone including Technion as they have a November 25, 2021posting of the press release.
A June 7, 2021 news item on phys.org announces research into a new method for generating electricity (Note: A link has been removed),
MIT [Massachusetts Institute of Technology] engineers have discovered a new way of generating electricity using tiny carbon particles that can create a current simply by interacting with liquid surrounding them.
The liquid, an organic solvent, draws electrons out of the particles, generating a current that could be used to drive chemical reactions or to power micro- or nanoscale robots, the researchers say.
“This mechanism is new, and this way of generating energy is completely new,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT. “This technology is intriguing because all you have to do is flow a solvent through a bed of these particles. This allows you to do electrochemistry, but with no wires.”
In a new study describing this phenomenon, the researchers showed that they could use this electric current to drive a reaction known as alcohol oxidation — an organic chemical reaction that is important in the chemical industry.
Strano is the senior author of the paper, which appears today [June 7, 2021] in Nature Communications. The lead authors of the study are MIT graduate student Albert Tianxiang Liu and former MIT researcher Yuichiro Kunai. Other authors include former graduate student Anton Cottrill, postdocs Amir Kaplan and Hyunah Kim, graduate student Ge Zhang, and recent MIT graduates Rafid Mollah and Yannick Eatmon.
The new discovery grew out of Strano’s research on carbon nanotubes — hollow tubes made of a lattice of carbon atoms, which have unique electrical properties. In 2010, Strano demonstrated, for the first time, that carbon nanotubes can generate “thermopower waves.” When a carbon nanotube is coated with layer of fuel, moving pulses of heat, or thermopower waves, travel along the tube, creating an electrical current.
That work led Strano and his students to uncover a related feature of carbon nanotubes. They found that when part of a nanotube is coated with a Teflon-like polymer, it creates an asymmetry that makes it possible for electrons to flow from the coated to the uncoated part of the tube, generating an electrical current. Those electrons can be drawn out by submerging the particles in a solvent that is hungry for electrons.
To harness this special capability, the researchers created electricity-generating particles by grinding up carbon nanotubes and forming them into a sheet of paper-like material. One side of each sheet was coated with a Teflon-like polymer, and the researchers then cut out small particles, which can be any shape or size. For this study, they made particles that were 250 microns by 250 microns.
When these particles are submerged in an organic solvent such as acetonitrile, the solvent adheres to the uncoated surface of the particles and begins pulling electrons out of them.
“The solvent takes electrons away, and the system tries to equilibrate by moving electrons,” Strano says. “There’s no sophisticated battery chemistry inside. It’s just a particle and you put it into solvent and it starts generating an electric field.”
The current version of the particles can generate about 0.7 volts of electricity per particle. In this study, the researchers also showed that they can form arrays of hundreds of particles in a small test tube. This “packed bed” reactor generates enough energy to power a chemical reaction called an alcohol oxidation, in which an alcohol is converted to an aldehyde or a ketone. Usually, this reaction is not performed using electrochemistry because it would require too much external current.
“Because the packed bed reactor is compact, it has more flexibility in terms of applications than a large electrochemical reactor,” Zhang says. “The particles can be made very small, and they don’t require any external wires in order to drive the electrochemical reaction.”
In future work, Strano hopes to use this kind of energy generation to build polymers using only carbon dioxide as a starting material. In a related project, he has already created polymers that can regenerate themselves using carbon dioxide as a building material, in a process powered by solar energy. This work is inspired by carbon fixation, the set of chemical reactions that plants use to build sugars from carbon dioxide, using energy from the sun.
In the longer term, this approach could also be used to power micro- or nanoscale robots. Strano’s lab has already begun building robots at that scale, which could one day be used as diagnostic or environmental sensors. The idea of being able to scavenge energy from the environment to power these kinds of robots is appealing, he says.
“It means you don’t have to put the energy storage on board,” he says. “What we like about this mechanism is that you can take the energy, at least in part, from the environment.”
Since COVID-19, we’ve been advised to wear face masks. It seems some of them may not be as safe as we assumed. First, the Health Canada advisory that was issued today, April 2, 2021 and then excerpts from an in-depth posting by Dr. Andrew Maynard (associate dean in the Arizona State University College of Global Futures) about the advisory and the use of graphene in masks.
Health Canada is advising Canadians not to use face masks that contain graphene because there is a potential that they could inhale graphene particles, which may pose health risks.
Graphene is a novel nanomaterial (materials made of tiny particles) reported to have antiviral and antibacterial properties. Health Canada conducted a preliminary scientific assessment after being made aware that masks containing graphene have been sold with COVID-19 claims and used by adults and children in schools and daycares. Health Canada believes they may also have been distributed for use in health care settings.
Health Canada’s preliminary assessment of available research identified that inhaled graphene particles had some potential to cause early lung toxicity in animals. However, the potential for people to inhale graphene particles from face masks and the related health risks are not yet known, and may vary based on mask design. The health risk to people of any age is not clear. Variables, such as the amount and duration of exposure, and the type and characteristics of the graphene material used, all affect the potential to inhale particles and the associated health risks. Health Canada has requested data from mask manufacturers to assess the potential health risks related to their masks that contain graphene.
Until the Department completes a thorough scientific assessment and has established the safety and effectiveness of graphene-containing face masks, it is taking the precautionary approach of removing them from the market while continuing to gather and assess information. Health Canada has directed all known distributors, importers and manufacturers to stop selling and to recall the affected products. Additionally, Health Canada has written to provinces and territories advising them to stop distribution and use of masks containing graphene. The Department will continue to take appropriate action to stop the import and sale of graphene face masks.
Face masks labelled as containing graphene or biomass graphene.
What you should do
Do not use face masks labelled to contain graphene or biomass graphene.
Consult your health care provider if you have used graphene face masks and have health concerns, such as new or unexplained shortness of breath, discomfort or difficulty breathing.
Dr. Andrew Maynard’s Edge of Innovation series features a March 26, 2021 posting about the use of graphene in masks (Note: Links have been removed),
Face masks should protect you, not place you in greater danger. However, last Friday Radio Canada revealed that residents of Quebec and Ottawa were being advised not to use specific types of graphene-containing masks as they could potentially be harmful.
The offending material in the masks is graphene — a form of carbon that consists of nanoscopically thin flakes of hexagonally-arranged carbon atoms. It’s a material that has a number of potentially beneficial properties, including the ability to kill bacteria and viruses when they’re exposed to it.
Yet despite its many potential uses, the scientific jury is still out when it comes to how safe the material is.
As with all materials, the potential health risks associated with graphene depend on whether it can get into the body, where it goes if it can, what it does when it gets there, and how much of it is needed to cause enough damage to be of concern.
Unfortunately, even though these are pretty basic questions, there aren’t many answers forthcoming when it comes to the substance’s use in face masks.
Early concerns around graphene were sparked by previous research on another form of carbon — carbon nanotubes. It turns out that some forms of these fiber-like materials can cause serious harm if inhaled. And following on from research here, a natural next-question to ask is whether carbon nanotubes’ close cousin graphene comes with similar concerns.
Because graphene lacks many of the physical and chemical aspects of carbon nanotubes that make them harmful (such as being long, thin, and hard for the body to get rid of), the indications are that the material is safer than its nanotube cousins. But safer doesn’t mean safe. And current research indicates that this is not a material that should be used where it could potentially be inhaled, without a good amount of safety testing first.
When it comes to inhaling graphene, the current state of the science indicates that if the material can get into the lower parts of the lungs (the respirable or alveolar region) it can lead to an inflammatory response at high enough concentrations.
There is some evidence that adverse responses are relatively short-lived, and that graphene particles can be broken down and disposed of by the lungs’ defenses.
This is good news as it means that there are less likely to be long-term health impacts from inhaling the material.
There’s also evidence that graphene, unlike some forms of thin, straight carbon nanotubes, does not migrate to the outside layers of the lungs where it could potentially do a lot more damage.
Again, this is encouraging as it suggests that graphene is unlikely to lead to serious long-term health impacts like mesothelioma.
However, research also shows that this is not a benign material. Despite being made of carbon — and it’s tempting to think of carbon as being safe, just because we’re familiar with it — there is some evidence that the jagged edges of some graphene particles can harm cells, leading to local damage as the body responds to any damage the material causes.
There are also concerns, although they are less well explored in the literature, that some forms of graphene may be carriers for nanometer-sized metal particles that can be quite destructive in the lungs. This is certainly the case with some carbon nanotubes, as the metallic catalyst particles used to manufacture them become embedded in the material, and contribute to its toxicity.
The long and short of this is that, while there are still plenty of gaps in our knowledge around how much graphene it’s safe to inhale, inhaling small graphene particles probably isn’t a great idea unless there’s been comprehensive testing to show otherwise.
And this brings us to graphene-containing face masks.
Here, it’s important to stress that we don’t yet know if graphene particles are being released and, if they are, whether they are being released in sufficient quantities to cause health effects. And there are indications that, if there are health risks, these may be relatively short-term — simply because graphene particles may be effectively degraded by the lungs’ defenses.
At the same time, it seems highly irresponsible to include a material with unknown inhalation risks in a product that is intimately associated with inhalation. Especially when there are a growing number of face masks available that claim to use graphene.
… There are millions of graphene face masks and respirators being sold and used around the world. And while the unfolding news focuses on Quebec and one particular type of face mask, this is casting uncertainty over the safety of any graphene-containing masks that are being sold.
And this uncertainty will persist until manufacturers and regulators provide data indicating that they have tested the products for the release and subsequent inhalation of fine graphene particles, and shown the risks to be negligible.
I strongly recommend reading, in its entirety , Dr. Maynard’s March 26, 2021 posting, Which he has updated twice since first posting the story.
In short. you may want to hold off before buying a mask with graphene until there’s more data about safety.
What a great image of bones! This December 3, 2020 University of Arkansas news release (also on EurekAlert) by Matt McGowan features research focused on bone material looks exciting. The date for the second study citation and link that I have listed (at the end of this posting) suggests the more recent study may have been initially overlooked in the deluge of COVID-19 research we are experiencing,
University of Arkansas researchers Marco Fielder and Arun Nair have conducted the first study of the combined nanoscale effects of water and mineral content on the deformation mechanisms and thermal properties of collagen, the essence of bone material.
The researchers also compared the results to the same properties of non-mineralized collagen reinforced with carbon nanotubes, which have shown promise as a reinforcing material for bio-composites. This research aids in the development of synthetic materials to mimic bone.
Using molecular dynamics — in this case a computer simulation of the physical movements of atoms and molecules — Nair and Fielder examined the mechanics and thermal properties of collagen-based bio-composites containing different weight percentages of minerals, water and carbon nanotubes when subjected to external loads.
They found that variations of water and mineral content had a strong impact on the mechanical behavior and properties of the bio-composites, the structure of which mimics nanoscale bone composition. With increased hydration, the bio-composites became more vulnerable to stress. Additionally, Nair and Fielder found that the presence of carbon nanotubes in non-mineralized collagen reduced the deformation of the gap regions.
The researchers also tested stiffness, which is the standard measurement of a material’s resistance to deformation. Both mineralized and non-mineralized collagen bio-composites demonstrated less stability with greater water content. Composites with 40% mineralization were twice as strong as those without minerals, regardless of the amount of water content. Stiffness of composites with carbon nanotubes was comparable to that of the mineralized collagen.
“As the degree of mineralization or carbon nanotube content of the collagenous bio-composites increased, the effect of water to change the magnitude of deformation decreased,” Fielder said.
The bio-composites made of collagen and carbon nanotubes were also found to have a higher specific heat than the studied mineralized collagen bio-composites, making them more likely to be resistant to thermal damage that could occur during implantation or functional use of the composite. Like most biological materials, bone is a hierarchical – with different structures at different length scales. At the microscale level, bone is made of collagen fibers, composed of smaller nanofibers called fibrils, which are a composite of collagen proteins, mineralized crystals called apatite and water. Collagen fibrils overlap each other in some areas and are separated by gaps in other areas.
“Though several studies have characterized the mechanics of fibrils, the effects of variation and distribution of water and mineral content in fibril gap and overlap regions are unexplored,” said Nair, who is an associate professor of mechanical engineering. “Exploring these regions builds an understanding of the structure of bone, which is important for uncovering its material properties. If we understand these properties, we can design and build better bio-inspired materials and bio-composites.”
Here are links and citations for both papers mentioned in the news release,