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Empa researcher Simon Annaheim is working to develop a mattress for newborn babies. Image: Empa
11.03.2024

Medical textiles and sensors: Smart protection for delicate skin

Skin injuries caused by prolonged pressure often occur in people who are unable to change their position independently – such as sick newborns in hospitals or elderly people. Thanks to successful partnerships with industry and research, Empa scientists are now launching two smart solutions for pressure sores.

If too much pressure is applied to our skin over a long period of time, it becomes damaged. Populations at high risk of such pressure injuries include people in wheelchairs, newborns in intensive care units and the elderly. The consequences are wounds, infections and pain.

Skin injuries caused by prolonged pressure often occur in people who are unable to change their position independently – such as sick newborns in hospitals or elderly people. Thanks to successful partnerships with industry and research, Empa scientists are now launching two smart solutions for pressure sores.

If too much pressure is applied to our skin over a long period of time, it becomes damaged. Populations at high risk of such pressure injuries include people in wheelchairs, newborns in intensive care units and the elderly. The consequences are wounds, infections and pain.

Treatment is complex and expensive: Healthcare costs of around 300 million Swiss francs are incurred every year. "In addition, existing illnesses can be exacerbated by such pressure injuries," says Empa researcher Simon Annaheim from the Biomimetic Membranes and Textiles laboratory in St. Gallen. According to Annaheim, it would be more sustainable to prevent tissue damage from occurring in the first place. Two current research projects involving Empa researchers are now advancing solutions: A pressure-equalizing mattress for newborns in intensive care units and a textile sensor system for paraplegics and bedridden people are being developed.

Optimally nestled at the start of life
The demands of our skin are completely different depending on age: In adults, the friction of the skin on the lying surface, physical shear forces in the tissue and the lack of breathability of textiles are the main risk factors. In contrast, the skin of newborns receiving intensive care is extremely sensitive per se, and any loss of fluid and heat through the skin can become a problem. "While these particularly vulnerable babies are being nursed back to health, the lying situation should not cause any additional complications," says Annaheim. He thinks conventional mattresses are not appropriate for newborns with very different weights and various illnesses. Annaheim's team is therefore working with researchers from ETH Zurich, the Zurich University of Applied Sciences (ZHAW) and the University Children's Hospital Zurich to find an optimal lying surface for babies' delicate skin. This mattress should be able to adapt individually to the body in order to help children with a difficult start in life.

In order to do this, the researchers first determined the pressure conditions in the various regions of the newborn's body. "Our pressure sensors showed that the head, shoulders and lower spine are the areas with the greatest risk of pressure sores," says Annaheim. These findings were incorporated into the development of a special kind of air-filled mattress: With the help of pressure sensors and a microprocessor, its three chambers can be filled precisely via an electronic pump so that the pressure in the respective areas is minimized. An infrared laser process developed at Empa made it possible to produce the mattress from a flexible, multi-layered polymer membrane that is gentle on the skin and has no irritating seams.

After a multi-stage development process in the laboratory, the first small patients were allowed to lie on the prototype mattress. The effect was immediately noticeable when the researchers filled the mattress with air to varying degrees depending on the individual needs of the babies: Compared to a conventional foam mattress, the prototype reduced the pressure on the vulnerable parts of the body by up to 40 percent.

Following this successful pilot study, the prototype is now being optimized in the Empa labs. Simon Annaheim and doctoral student Tino Jucker will soon be starting a larger-scale study with the new mattress with the Department of Intensive Care Medicine & Neonatology at University Children's Hospital Zurich.

Intelligent sensors prevent injuries
In another project, Empa researchers are working on preventing so-called pressure ulcer tissue damage in adults. This involves converting the risk factors of pressure and circulatory disorders into helpful warning signals.

If you lie in the same position for a long time, pressure and circulatory problems lead to an undersupply of oxygen to the tissue. While the lack of oxygen triggers a reflex to move in healthy people, this neurological feedback loop can be disrupted in people with paraplegia or coma patients, for example. Here, smart sensors can help to provide early warning of the risk of tissue damage.

In the ProTex project, a team of researchers from Empa, the University of Bern, the OST University of Applied Sciences and Bischoff Textil AG in St. Gallen has developed a sensor system made of smart textiles with associated data analysis in real time. "The skin-compatible textile sensors contain two different functional polymer fibers," says Luciano Boesel from Empa's Biomimetic Membranes and Textiles laboratory in St. Gallen. In addition to pressure-sensitive fibers, the researchers integrated light-conducting polymer fibers (POFs), which are used to measure oxygen. "As soon as the oxygen content in the skin drops, the highly sensitive sensor system signals an increasing risk of tissue damage," explains Boesel. The data is then transmitted directly to the patient or to the nursing staff. This means, for instance, that a lying person can be repositioned in good time before the tissue is damaged.

Patented technology
The technology behind this also includes a novel microfluidic wet spinning process developed at Empa for the production of POFs. It allows precise control of the polymer components in the micrometer range and smoother, more environmentally friendly processing of the fibers. The microfluidic process is one of three patents that have emerged from the ProTex project to date.

Another product is a breathable textile sensor that is worn directly on the skin. The spin-off Sensawear in Bern, which emerged from the project in 2023, is currently pushing ahead with the market launch. Empa researcher Boesel is also convinced: "The findings and technologies from ProTex will enable further applications in the field of wearable sensor technology and smart clothing in the future."

Source:

Dr. Andrea Six, Empa

Researchers led by Bernd Nowack have investigated the release of nanoparticles during the washing of polyester textiles. Image: Empa Image: Empa
14.02.2024

Release of oligomers from polyester textiles

When nanoplastics are not what they seem ... Textiles made of synthetic fibers release micro- and nanoplastics during washing. Empa researchers have now been able to show: Some of the supposed nanoplastics do not actually consist of plastic particles, but of water-insoluble oligomers. The effects they have on humans and the environment are not yet well-understood.

Plastic household items and clothing made of synthetic fibers release microplastics: particles less than five millimetres in size that can enter the environment unnoticed. A small proportion of these particles are so small that they are measured in nanometers. Such nanoplastics are the subject of intensive research, as nanoplastic particles can be absorbed into the human body due to their small size – but, as of today, little is known about their potential toxicity.

When nanoplastics are not what they seem ... Textiles made of synthetic fibers release micro- and nanoplastics during washing. Empa researchers have now been able to show: Some of the supposed nanoplastics do not actually consist of plastic particles, but of water-insoluble oligomers. The effects they have on humans and the environment are not yet well-understood.

Plastic household items and clothing made of synthetic fibers release microplastics: particles less than five millimetres in size that can enter the environment unnoticed. A small proportion of these particles are so small that they are measured in nanometers. Such nanoplastics are the subject of intensive research, as nanoplastic particles can be absorbed into the human body due to their small size – but, as of today, little is known about their potential toxicity.

Empa researchers from Bernd Nowack's group in the Technology and Society laboratory have now joined forces with colleagues from China to take a closer look at nanoparticles released from textiles. Tong Yang, first author of the study, carried out the investigations during his doctorate at Empa. In earlier studies, Empa researchers were already able to demonstrate that both micro- and nanoplastics are released when polyester is washed. A detailed examination of the released nanoparticles released has now shown that not everything that appears to be nanoplastic at first glance actually is nanoplastic.

To a considerable extent, the released particles were in fact not nanoplastics, but clumps of so-called oligomers, i.e. small to medium-sized molecules that represent an intermediate stage between the long-chained polymers and their individual building blocks, the monomers. These molecules are even smaller than nanoplastic particles, and hardly anything is known about their toxicity either. The researchers published their findings in the journal Nature Water.

For the study, the researchers examined twelve different polyester fabrics, including microfiber, satin and jersey. The fabric samples were washed up to four times and the nanoparticles released in the process were analyzed and characterized. Not an easy task, says Bernd Nowack. "Plastic, especially nanoplastics, is everywhere, including on our devices and utensils," says the scientist. "When measuring nanoplastics, we have to take this 'background noise' into account."

Large proportion of soluble particles
The researchers used an ethanol bath to distinguish nanoplastics from clumps of oligomers. Plastic pieces, no matter how small, do not dissolve in ethanol, but aggregations of oligomers do. The result: Around a third to almost 90 percent of the nanoparticles released during washing could be dissolved in ethanol. "This allowed us to show that not everything that looks like nanoplastics at first glance is in fact nanoplastics," says Nowack.

It is not yet clear whether the release of so-called nanoparticulate oligomers during the washing of textiles has negative effects on humans and the environment. "With other plastics, studies have already shown that nanoparticulate oligomers are more toxic than nanoplastics," says Nowack. "This is an indication that this should be investigated more closely." However, the researchers were able to establish that the nature of the textile and the cutting method – scissors or laser – have no major influence on the quantity of particles released.

The mechanism of release has not been clarified yet either – neither for nanoplastics nor for the oligomer particles. The good news is that the amount of particles released decreases significantly with repeated washes. It is conceivable that the oligomer particles are created during the manufacturing of the textile or split off from the fibers through chemical processes during storage. Further studies are also required in this area.

Nowack and his team are focusing on larger particles for the time being: In their next project, they want to investigate which fibers are released during washing of textiles made from renewable raw materials and whether these could be harmful to the environment and health. "Semi-synthetic textiles such as viscose or lyocell are being touted as a replacement for polyester," says Nowack. "But we don't yet know whether they are really better when it comes to releasing fibers."

Source:

Empa

Photo: Sibi Suku, unsplash
29.01.2024

Naturalistic silk spun from artificial spider gland

Researchers led by Keiji Numata at the RIKEN Center for Sustainable Resource Science in Japan, along with colleagues from the RIKEN Pioneering Research Cluster, have succeeded in creating a device that spins artificial spider silk that closely matches what spiders naturally produce. The artificial silk gland was able to re-create the complex molecular structure of silk by mimicking the various chemical and physical changes that naturally occur in a spider’s silk gland. This eco-friendly innovation is a big step towards sustainability and could impact several industries. This study was published January 15 in the scientific journal Nature Communications.

Researchers led by Keiji Numata at the RIKEN Center for Sustainable Resource Science in Japan, along with colleagues from the RIKEN Pioneering Research Cluster, have succeeded in creating a device that spins artificial spider silk that closely matches what spiders naturally produce. The artificial silk gland was able to re-create the complex molecular structure of silk by mimicking the various chemical and physical changes that naturally occur in a spider’s silk gland. This eco-friendly innovation is a big step towards sustainability and could impact several industries. This study was published January 15 in the scientific journal Nature Communications.

Famous for its strength, flexibility, and light weight, spider silk has a tensile strength that is comparable to steel of the same diameter, and a strength to weight ratio that is unparalleled. Added to that, it’s biocompatible, meaning that it can be used in medical applications, as well as biodegradable. So why isn’t everything made from spider silk? Large-scale harvesting of silk from spiders has proven impractical for several reasons, leaving it up to scientists to develop a way to produce it in the laboratory.

Spider silk is a biopolymer fiber made from large proteins with highly repetitive sequences, called spidroins. Within the silk fibers are molecular substructures called beta sheets, which must be aligned properly for the silk fibers to have their unique mechanical properties. Re-creating this complex molecular architecture has confounded scientists for years. Rather than trying to devise the process from scratch, RIKEN scientists took a biomimicry approach. As Numata explains, “in this study, we attempted to mimic natural spider silk production using microfluidics, which involves the flow and manipulation of small amounts of fluids through narrow channels. Indeed, one could say that that the spider’s silk gland functions as a sort of natural microfluidic device.”

The device developed by the researchers looks like a small rectangular box with tiny channels grooved into it. Precursor spidroin solution is placed at one end and then pulled towards the other end by means of negative pressure. As the spidroins flow through the microfluidic channels, they are exposed to precise changes in the chemical and physical environment, which are made possible by the design of the microfluidic system. Under the correct conditions, the proteins self-assembled into silk fibers with their characteristic complex structure.

The researchers experimented to find these correct conditions, and eventually were able to optimize the interactions among the different regions of the microfluidic system. Among other things, they discovered that using force to push the proteins through did not work; only when they used negative pressure to pull the spidroin solution could continuous silk fibers with the correct telltale alignment of beta sheets be assembled.

“It was surprising how robust the microfluidic system was, once the different conditions were established and optimized,” says Senior Scientist Ali Malay, one of the paper’s co-authors. “Fiber assembly was spontaneous, extremely rapid, and highly reproducible. Importantly, the fibers exhibited the distinct hierarchical structure that is found in natural silk fiber.”

The ability to artificially produce silk fibers using this method could provide numerous benefits. Not only could it help reduce the negative impact that current textile manufacturing has on the environment, but the biodegradable and biocompatible nature of spider silk makes it ideal for biomedical applications, such as sutures and artificial ligaments.

“Ideally, we want to have a real-world impact,” says Numata. “For this to occur, we will need to scale-up our fiber-production methodology and make it a continuous process. We will also evaluate the quality of our artificial spider silk using several metrics and make further improvements from there.”

Source:

RIKEN Center for Sustainable Resource Science, Japan

Converting CO2 to Solid Carbon Nanofibers (c) Zhenhua Xie/Brookhaven National Laboratory and Columbia University; Erwei Huang/Brookhaven National Laboratory
22.01.2024

Converting CO2 to Solid Carbon Nanofibers

Tandem electrocatalytic-thermocatalytic conversion could help offset emissions of potent greenhouse gas by locking carbon away in a useful material.

Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and Columbia University have developed a way to convert carbon dioxide (CO2), a potent greenhouse gas, into carbon nanofibers, materials with a wide range of unique properties and many potential long-term uses. Their strategy uses tandem electrochemical and thermochemical reactions run at relatively low temperatures and ambient pressure. As the scientists describe in the journal Nature Catalysis, this approach could successfully lock carbon away in a useful solid form to offset or even achieve negative carbon emissions.

Tandem electrocatalytic-thermocatalytic conversion could help offset emissions of potent greenhouse gas by locking carbon away in a useful material.

Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and Columbia University have developed a way to convert carbon dioxide (CO2), a potent greenhouse gas, into carbon nanofibers, materials with a wide range of unique properties and many potential long-term uses. Their strategy uses tandem electrochemical and thermochemical reactions run at relatively low temperatures and ambient pressure. As the scientists describe in the journal Nature Catalysis, this approach could successfully lock carbon away in a useful solid form to offset or even achieve negative carbon emissions.

“You can put the carbon nanofibers into cement to strengthen the cement,” said Jingguang Chen, a professor of chemical engineering at Columbia with a joint appointment at Brookhaven Lab who led the research. “That would lock the carbon away in concrete for at least 50 years, potentially longer. By then, the world should be shifted to primarily renewable energy sources that don’t emit carbon.”

As a bonus, the process also produces hydrogen gas (H2), a promising alternative fuel that, when used, creates zero emissions.

Capturing or converting carbon?
The idea of capturing CO2 or converting it to other materials to combat climate change is not new. But simply storing CO2 gas can lead to leaks. And many CO2 conversions produce carbon-based chemicals or fuels that are used right away, which releases CO2 right back into the atmosphere.

“The novelty of this work is that we are trying to convert CO2 into something that is value-added but in a solid, useful form,” Chen said.

Such solid carbon materials—including carbon nanotubes and nanofibers with dimensions measuring billionths of a meter—have many appealing properties, including strength and thermal and electrical conductivity. But it’s no simple matter to extract carbon from carbon dioxide and get it to assemble into these fine-scale structures. One direct, heat-driven process requires temperatures in excess of 1,000 degrees Celsius.

“It’s very unrealistic for large-scale CO2 mitigation,” Chen said. “In contrast, we found a process that can occur at about 400 degrees Celsius, which is a much more practical, industrially achievable temperature.”

The tandem two-step
The trick was to break the reaction into stages and to use two different types of catalysts—materials that make it easier for molecules to come together and react.

“If you decouple the reaction into several sub-reaction steps you can consider using different kinds of energy input and catalysts to make each part of the reaction work,” said Brookhaven Lab and Columbia research scientist Zhenhua Xie, lead author on the paper.

The scientists started by realizing that carbon monoxide (CO) is a much better starting material than CO2 for making carbon nanofibers (CNF). Then they backtracked to find the most efficient way to generate CO from CO2.

Earlier work from their group steered them to use a commercially available electrocatalyst made of palladium supported on carbon. Electrocatalysts drive chemical reactions using an electric current. In the presence of flowing electrons and protons, the catalyst splits both CO2 and water (H2O) into CO and H2.

For the second step, the scientists turned to a heat-activated thermocatalyst made of an iron-cobalt alloy. It operates at temperatures around 400 degrees Celsius, significantly milder than a direct CO2-to-CNF conversion would require. They also discovered that adding a bit of extra metallic cobalt greatly enhances the formation of the carbon nanofibers.

“By coupling electrocatalysis and thermocatalysis, we are using this tandem process to achieve things that cannot be achieved by either process alone,” Chen said.

Catalyst characterization
To discover the details of how these catalysts operate, the scientists conducted a wide range of experiments. These included computational modeling studies, physical and chemical characterization studies at Brookhaven Lab’s National Synchrotron Light Source II (NSLS-II)—using the Quick X-ray Absorption and Scattering (QAS) and Inner-Shell Spectroscopy (ISS) beamlines—and microscopic imaging at the Electron Microscopy facility at the Lab’s Center for Functional Nanomaterials (CFN).

On the modeling front, the scientists used “density functional theory” (DFT) calculations to analyze the atomic arrangements and other characteristics of the catalysts when interacting with the active chemical environment.

“We are looking at the structures to determine what are the stable phases of the catalyst under reaction conditions,” explained study co-author Ping Liu of Brookhaven’s Chemistry Division who led these calculations. “We are looking at active sites and how these sites are bonding with the reaction intermediates. By determining the barriers, or transition states, from one step to another, we learn exactly how the catalyst is functioning during the reaction.”

X-ray diffraction and x-ray absorption experiments at NSLS-II tracked how the catalysts change physically and chemically during the reactions. For example, synchrotron x-rays revealed how the presence of electric current transforms metallic palladium in the catalyst into palladium hydride, a metal that is key to producing both H2 and CO in the first reaction stage.

For the second stage, “We wanted to know what’s the structure of the iron-cobalt system under reaction conditions and how to optimize the iron-cobalt catalyst,” Xie said. The x-ray experiments confirmed that both an alloy of iron and cobalt plus some extra metallic cobalt are present and needed to convert CO to carbon nanofibers.

“The two work together sequentially,” said Liu, whose DFT calculations helped explain the process.

“According to our study, the cobalt-iron sites in the alloy help to break the C-O bonds of carbon monoxide. That makes atomic carbon available to serve as the source for building carbon nanofibers. Then the extra cobalt is there to facilitate the formation of the C-C bonds that link up the carbon atoms,” she explained.

Recycle-ready, carbon-negative
“Transmission electron microscopy (TEM) analysis conducted at CFN revealed the morphologies, crystal structures, and elemental distributions within the carbon nanofibers both with and without catalysts,” said CFN scientist and study co-author Sooyeon Hwang.

The images show that, as the carbon nanofibers grow, the catalyst gets pushed up and away from the surface. That makes it easy to recycle the catalytic metal, Chen said.

“We use acid to leach the metal out without destroying the carbon nanofiber so we can concentrate the metals and recycle them to be used as a catalyst again,” he said.

This ease of catalyst recycling, commercial availability of the catalysts, and relatively mild reaction conditions for the second reaction all contribute to a favorable assessment of the energy and other costs associated with the process, the researchers said.

“For practical applications, both are really important—the CO2 footprint analysis and the recyclability of the catalyst,” said Chen. “Our technical results and these other analyses show that this tandem strategy opens a door for decarbonizing CO2 into valuable solid carbon products while producing renewable H2.”

If these processes are driven by renewable energy, the results would be truly carbon-negative, opening new opportunities for CO2 mitigation.

Source:

Brookhaven National Laboratory

New conductive, cotton-based fiber developed for smart textiles Photo: Dean Hare, WSU Photo Services
29.12.2023

New conductive, cotton-based fiber developed for smart textiles

A single strand of fiber developed at Washington State University has the flexibility of cotton and the electric conductivity of a polymer, called polyaniline.

The newly developed material showed good potential for wearable e-textiles. The WSU researchers tested the fibers with a system that powered an LED light and another that sensed ammonia gas, detailing their findings in the journal Carbohydrate Polymers.

“We have one fiber in two sections: one section is the conventional cotton: flexible and strong enough for everyday use, and the other side is the conductive material,” said Hang Liu, WSU textile researcher and the study’s corresponding author. “The cotton can support the conductive material which can provide the needed function.”

A single strand of fiber developed at Washington State University has the flexibility of cotton and the electric conductivity of a polymer, called polyaniline.

The newly developed material showed good potential for wearable e-textiles. The WSU researchers tested the fibers with a system that powered an LED light and another that sensed ammonia gas, detailing their findings in the journal Carbohydrate Polymers.

“We have one fiber in two sections: one section is the conventional cotton: flexible and strong enough for everyday use, and the other side is the conductive material,” said Hang Liu, WSU textile researcher and the study’s corresponding author. “The cotton can support the conductive material which can provide the needed function.”

While more development is needed, the idea is to integrate fibers like these into apparel as sensor patches with flexible circuits. These patches could be part of uniforms for firefighters, soldiers or workers who handle chemicals to detect for hazardous exposures. Other applications include health monitoring or exercise shirts that can do more than current fitness monitors.

“We have some smart wearables, like smart watches, that can track your movement and human vital signs, but we hope that in the future your everyday clothing can do these functions as well,” said Liu. “Fashion is not just color and style, as a lot of people think about it: fashion is science.”

In this study, the WSU team worked to overcome the challenges of mixing the conductive polymer with cotton cellulose. Polymers are substances with very large molecules that have repeating patterns. In this case, the researchers used polyaniline, also known as PANI, a synthetic polymer with conductive properties already used in applications such as printed circuit board manufacturing.

While intrinsically conductive, polyaniline is brittle and by itself, cannot be made into a fiber for textiles. To solve this, the WSU researchers dissolved cotton cellulose from recycled t-shirts into a solution and the conductive polymer into another separate solution. These two solutions were then merged together side-by-side, and the material was extruded to make one fiber.

The result showed good interfacial bonding, meaning the molecules from the different materials would stay together through stretching and bending.

Achieving the right mixture at the interface of cotton cellulose and polyaniline was a delicate balance, Liu said.

“We wanted these two solutions to work so that when the cotton and the conductive polymer contact each other they mix to a certain degree to kind of glue together, but we didn’t want them to mix too much, otherwise the conductivity would be reduced,” she said.

Additional WSU authors on this study included first author Wangcheng Liu as well as Zihui Zhao, Dan Liang, Wei-Hong Zhong and Jinwen Zhang. This research received support from the National Science Foundation and the Walmart Foundation Project.

Source:

Sara Zaske, WSU News & Media Relations

Chemist Unlocks Plastic Alternatives Using Proteins and Clothing Scraps Photo: Challa Kumar, professor emeritus of chemistry, in his lab. (Contributed photo)
21.12.2023

Chemist Unlocks Plastic Alternatives Using Proteins and Clothing Scraps

Challa Kumar has developed methods to create novel plastic-like materials using proteins and fabric.

Every year, 400 million tons of plastic waste are generated worldwide. Between 19 and 23 million tons of that plastic waste makes its way into aquatic ecosystems, and the remaining goes into the ground. An additional 92 million tons of cloth waste is generated annually.

Challa Kumar, professor emeritus of chemistry, “fed up” with the tremendous amount of toxic waste people continually pump into the environment, felt compelled to do something. As a chemist, doing something meant using his expertise to develop new, sustainable materials.

“Everyone should think about replacing fossil fuel-based materials with natural materials anywhere they can to help our civilization to survive,” Kumar says. “The house is on fire, we can’t wait. If the house is on fire and you start digging a well – that is not going to work. It’s time to start pouring water on the house.”

Challa Kumar has developed methods to create novel plastic-like materials using proteins and fabric.

Every year, 400 million tons of plastic waste are generated worldwide. Between 19 and 23 million tons of that plastic waste makes its way into aquatic ecosystems, and the remaining goes into the ground. An additional 92 million tons of cloth waste is generated annually.

Challa Kumar, professor emeritus of chemistry, “fed up” with the tremendous amount of toxic waste people continually pump into the environment, felt compelled to do something. As a chemist, doing something meant using his expertise to develop new, sustainable materials.

“Everyone should think about replacing fossil fuel-based materials with natural materials anywhere they can to help our civilization to survive,” Kumar says. “The house is on fire, we can’t wait. If the house is on fire and you start digging a well – that is not going to work. It’s time to start pouring water on the house.”

Kumar has developed two technologies that use proteins and cloth, respectively, to create new materials. UConn’s Technology Commercialization Services (TCS) has filed provisional patents for both technologies.

Inspired by nature’s ability to construct a diverse array of functional materials, Kumar and his team developed a method to produce continuously tunable non-toxic materials.

“Chemistry is the only thing standing in our way,” Kumar says. “If we understand protein chemistry, we can make protein materials as strong as a diamond or as soft as a feather.”

The first innovation is a process to transform naturally occurring proteins into plastic-like materials. Kumar’s student, Ankarao Kalluri ’23 Ph.D., worked on this project.

Proteins have “reactor groups” on their surfaces which can react with substances with which they come into contact. Using his knowledge of how these groups work, Kumar and his team used a chemical link to bind protein molecules together.

This process creates a dimer – a molecule composed to two proteins. From there, the dimer is joined with another dimer to create tetramer, and so on until it becomes a large 3D molecule. This 3D aspect of the technology is unique, since most synthetic polymers are linear chains.

This novel 3D structure allows the new polymer to behave like a plastic. Just like the proteins of which it is made, the material can stretch, change shape, and fold. Thus, the material can be tailored via chemistry for a variety of specific applications.

Unlike synthetic polymers, because Kumar’s material is made of proteins and a bio-linking chemical, it can biodegrade, just like plant and animal proteins do naturally.

“Nature degrades proteins by ripping apart the amide bonds that are in them,” Kumar says. “It has enzymes to handle that sort of chemistry. We have the same amide linkages in our materials. So, the same enzymes that work in biology should also work on this material and biodegrade it naturally.”

In the lab, the team found that the material degrades within a few days in acidic solution. Now, they are investigating what happens if they bury this material in the ground, which is the fate of many post-consumer plastics.

They have demonstrated that the protein-based material can form a variety of plastic-like products, including coffee cup lids and thin transparent films. It could also be used to make fire-resistant roof tiles, or higher-end materials like, car doors, rocket cone tips, or heart valves.

The next steps for this technology are to continue testing their mechanical properties, like strength or flexibility, as well as toxicity.

“I think we need to have social consciousness that we cannot put out materials into the environment that are toxic,” Kumar says. “We just cannot. We have to stop doing that. And we cannot use materials derived from fossil fuels either.”

Kumar’s second technology uses a similar principle, but instead of just proteins, uses proteins reinforced with natural fibers, specifically cotton.

“We are creating a lot of textile waste each year due to the fast-changing fashion industry” Kumar says. “So why not use that waste to create useful materials – convert waste to wealth.”

Just like the plastic-like protein materials (called “Proteios,” derived from original Greek words), Kumar expects composite materials made from proteins and natural fibers will biodegrade without producing toxic waste.

In the lab, Kumar’s former student, doctoral candidate Adekeye Damilola, created many objects with protein-fabric composites, which include small shoes, desks, flowers, and chairs. This material contains textile fibers which serve as the linking agent with the proteins, rather than the cross-linking chemical Kumar uses for the protein-based plastics.

The crosslinking provides the novel material with the strength to withstand the weight that would be put on something like a chair or a table. The natural affinity between fibers and proteins is why it’s so hard to get food stains out of clothing. This same attraction makes strong protein-fabric materials.

While Kumar’s team has only worked with cotton so far, they expect other fiber materials, like hemp fibers or jute, would behave similarly due to their inherent but common chemical properties with cotton.

“The protein naturally adheres to the surface of the protein,” Kumar says. “We used that understanding to say ‘Hey, if it binds so tightly to cotton, why don’t we make a material out of it.’ And it works, it works amazingly.”

With the support of TCS, Professor Kumar is currently seeking industry partners to bring these technologies to market. For more information contact Michael Invernale at michael.invernale@uconn.edu.

Source:

Anna Zarra Aldrich '20 (CLAS), Office of the Vice President for Research

Berndt Köll on the Stubai Glacier: Initial field tests showed convincing results. (c) Lenzing AG
22.11.2023

Glacier protection rethought: Nonwovens made of cellulosic fibers

Protection for snow and ice: Cellulosic LENZING™ fibers offer solution for preservation of glacier mass

In field trials on Austrian glaciers, nonwovens made of cellulosic LENZING™ fibers are being used to cover glacier mass. They are showing promising results and offer a sustainable solution for glacier protection. Nonwovens containing fossil-based synthetic fibers might cause negative environmental consequences such as microplastics on glaciers.

Protection for snow and ice: Cellulosic LENZING™ fibers offer solution for preservation of glacier mass

In field trials on Austrian glaciers, nonwovens made of cellulosic LENZING™ fibers are being used to cover glacier mass. They are showing promising results and offer a sustainable solution for glacier protection. Nonwovens containing fossil-based synthetic fibers might cause negative environmental consequences such as microplastics on glaciers.

Geotextiles are already widely used to protect snow and ice on glaciers from melting. The use of nonwovens made from cellulosic LENZING™ fibers is now achieving a sustainable turnaround. Geotextiles show great success in Austria in protecting glaciers, which are highly endangered by global warming. By covering glacier mass, its melting is slowed down and mitigated. So far, the nonwovens used to protect glaciers are usually made of fossil-based synthetic fibers. The problem with that might occur as microplastics left behind after the summer flow down into the valley and can enter the food chain through small organisms and animals.

Sustainability from production to reuse
An innovative and sustainable solution for the protection of snow and ice is now possible with the help of nonwovens made of cellulosic LENZING™ fibers. "LENZING™ fibers are derived from renewable, responsibly managed wood sources and are produced in an environmentally responsible process. Thanks to their botanic origin, they have the ability to break down, returning into nature after use" explains Berndt Köll, Business & Innovation Manager at Lenzing.

In a field trial on the Stubai Glacier, the covering of a small area with the new material containing cellulosic LENZING™ fibers was tested for the first time. The result was convincing: 4 meters of ice mass could be saved from melting. Due to its success, the project is now being expanded. In 2023 field tests started in all Austrian glaciers, which are used for tourism.

"We are pleased with the positive results and see the project as a sustainable solution for glacier protection - not only in Austria, but beyond national borders," Berndt Köll continues. There should also be a possibility to explore for recycling after the nonwovens are used: These geotextiles can be recycled and ultimately used to make yarn for textile products.

Awarded with the Swiss BIO TOP
The sustainable glacier protection and its results also convinced the jury of industry experts of the BIO TOP, a major award for wood and material innovations in Switzerland. With this award innovative projects in the field of bio-based woods and materials are promoted and supported. At the award ceremony on September 20, 2023, Geotextiles containing LENZING™ fibers were honored with the award for its solution.

Source:

Lenzing AG

06.11.2023

Shape-shifting fiber can produce morphing fabrics

The low-cost FibeRobo, which is compatible with existing textile manufacturing techniques, could be used in adaptive performance wear or compression garments.

Researchers from MIT and Northeastern University developed a liquid crystal elastomer fiber that can change its shape in response to thermal stimuli. The fiber, which is fully compatible with existing textile manufacturing machinery, could be used to make morphing textiles, like a jacket that becomes more insulating to keep the wearer warm when temperatures drop.

The low-cost FibeRobo, which is compatible with existing textile manufacturing techniques, could be used in adaptive performance wear or compression garments.

Researchers from MIT and Northeastern University developed a liquid crystal elastomer fiber that can change its shape in response to thermal stimuli. The fiber, which is fully compatible with existing textile manufacturing machinery, could be used to make morphing textiles, like a jacket that becomes more insulating to keep the wearer warm when temperatures drop.

Instead of needing a coat for each season, imagine having a jacket that would dynamically change shape so it becomes more insulating to keep you warm as the temperature drops.
A programmable, actuating fiber developed by an interdisciplinary team of MIT researchers could someday make this vision a reality. Known as FibeRobo, the fiber contracts in response to an increase in temperature, then self-reverses when the temperature decreases, without any embedded sensors or other hard components.

The low-cost fiber is fully compatible with textile manufacturing techniques, including weaving looms, embroidery, and industrial knitting machines, and can be produced continuously by the kilometer. This could enable designers to easily incorporate actuation and sensing capabilities into a wide range of fabrics for myriad applications.

The fibers can also be combined with conductive thread, which acts as a heating element when electric current runs through it. In this way, the fibers actuate using electricity, which offers a user digital control over a textile’s form. For instance, a fabric could change shape based on any piece of digital information, such as readings from a heart rate sensor.

“We use textiles for everything. We make planes with fiber-reinforced composites, we cover the International Space Station with a radiation-shielding fabric, we use them for personal expression and performance wear. So much of our environment is adaptive and responsive, but the one thing that needs to be the most adaptive and responsive — textiles — is completely inert,” says Jack Forman, a graduate student in the Tangible Media Group of the MIT Media Lab, with a secondary affiliation at the Center for Bits and Atoms, and lead author of a paper on the actuating fiber.

He is joined on the paper by 11 other researchers at MIT and Northeastern University, including his advisors, Professor Neil Gershenfeld, who leads the Center for Bits and Atoms, and Hiroshi Ishii, the Jerome B. Wiesner Professor of Media Arts and Sciences and director of the Tangible Media Group. The research will be presented at the ACM Symposium on User Interface Software and Technology.

Morphing materials
The MIT researchers wanted a fiber that could actuate silently and change its shape dramatically, while being compatible with common textile manufacturing procedures. To achieve this, they used a material known as liquid crystal elastomer (LCE).

A liquid crystal is a series of molecules that can flow like liquid, but when they’re allowed to settle, they stack into a periodic crystal arrangement. The researchers incorporate these crystal structures into an elastomer network, which is stretchy like a rubber band.

As the LCE material heats up, the crystal molecules fall out of alignment and pull the elastomer network together, causing the fiber to contract. When the heat is removed, the molecules return to their original alignment, and the material to its original length, Forman explains.

By carefully mixing chemicals to synthesize the LCE, the researchers can control the final properties of the fiber, such as its thickness or the temperature at which it actuates.

They perfected a preparation technique that creates LCE fiber which can actuate at skin-safe temperatures, making it suitable for wearable fabrics.

“There are a lot of knobs we can turn. It was a lot of work to come up with this process from scratch, but ultimately it gives us a lot of freedom for the resulting fiber,” he adds.
However, the researchers discovered that making fiber from LCE resin is a finicky process. Existing techniques often result in a fused mass that is impossible to unspool.

Researchers are also exploring other ways to make functional fibers, such as by incorporating hundreds of microscale digital chips into a polymer, utilizing an activated fluidic system, or including piezoelectric material that can convert sound vibrations into electrical signals.

Fiber fabrication
Forman built a machine using 3D-printed and laser-cut parts and basic electronics to overcome the fabrication challenges. He initially built the machine as part of the graduate-level course MAS.865 (Rapid-Prototyping of Rapid-Prototyping Machines: How to Make Something that Makes [almost] Anything).

To begin, the thick and viscous LCE resin is heated, and then slowly squeezed through a nozzle like that of a glue gun. As the resin comes out, it is cured carefully using UV lights that shine on both sides of the slowly extruding fiber.

If the light is too dim, the material will separate and drip out of the machine, but if it is too bright, clumps can form, which yields bumpy fibers.

Then the fiber is dipped in oil to give it a slippery coating and cured again, this time with UV lights turned up to full blast, creating a strong and smooth fiber. Finally, it is collected into a top spool and dipped in powder so it will slide easily into machines for textile manufacturing.
From chemical synthesis to finished spool, the process takes about a day and produces approximately a kilometer of ready-to-use fiber.

“At the end of the day, you don’t want a diva fiber. You want a fiber that, when you are working with it, falls into the ensemble of materials — one that you can work with just like any other fiber material, but then it has a lot of exciting new capabilities,” Forman says.

Creating such a fiber took a great deal of trial and error, as well as the collaboration of researchers with expertise in many disciplines, from chemistry to mechanical engineering to electronics to design.

The resulting fiber, called FibeRobo, can contract up to 40 percent without bending, actuate at skin-safe temperatures (the skin-safe version of the fiber contracts up to about 25 percent), and be produced with a low-cost setup for 20 cents per meter, which is about 60 times cheaper than commercially available shape-changing fibers.

The fiber can be incorporated into industrial sewing and knitting machines, as well as nonindustrial processes like hand looms or manual crocheting, without the need for any process modifications.
The MIT researchers used FibeRobo to demonstrate several applications, including an adaptive sports bra made by embroidery that tightens when the user begins exercising.

They also used an industrial knitting machine to create a compression jacket for Forman’s dog, whose name is Professor. The jacket would actuate and “hug” the dog based on a Bluetooth signal from Forman’s smartphone. Compression jackets are commonly used to alleviate the separation anxiety a dog can feel while its owner is away.

In the future, the researchers want to adjust the fiber’s chemical components so it can be recyclable or biodegradable. They also want to streamline the polymer synthesis process so users without wet lab expertise could make it on their own.

Forman is excited to see the FibeRobo applications other research groups identify as they build on these early results. In the long run, he hopes FibeRobo can become something a maker could buy in a craft store, just like a ball of yarn, and use to easily produce morphing fabrics.

“LCE fibers come to life when integrated into functional textiles. It is particularly fascinating to observe how the authors have explored creative textile designs using a variety of weaving and knitting patterns,” says Lining Yao, the Cooper-Siegel Associate Professor of Human Computer Interaction at Carnegie Mellon University, who was not involved with this work.

This research was supported, in part, by the William Asbjornsen Albert Memorial Fellowship, the Dr. Martin Luther King Jr. Visiting Professor Program, Toppan Printing Co., Honda Research, Chinese Scholarship Council, and Shima Seiki. The team included Ozgun Kilic Afsar, Sarah Nicita, Rosalie (Hsin-Ju) Lin, Liu Yang, Akshay Kothakonda, Zachary Gordon, and Cedric Honnet at MIT; and Megan Hofmann and Kristen Dorsey at Northeastern University.

Source:

MIT and Northeastern University

Silk Provides the Building Blocks to Transform Modern Medicine Photo: Jenna Schad
31.10.2023

Silk Provides the Building Blocks to Transform Modern Medicine

Tufts researchers harness protein from silk to make virus-sensing gloves, surgical screws that dissolve in your body, and other next-generation biomedical materials

About a mile northwest of Tufts’ Medford/Somerville campus, on the fourth floor of a refurbished woolen factory, there is a shrine to silk. Glass vases filled with silkworm cocoons and washed silk fibers sit artfully on a shelf across from a colorful drawing of the life cycle of Bombyx mori, the domesticated silk moth. Farther in, more cocoons in wall-mounted cases border a large, close-up image of silk fibers, and displays hold dozens of prototypes made from silk, including smart fabrics, biosensors, a helmet that changes color upon impact, and potential replacements for materials like leather, plastic, and particle board.

Tufts researchers harness protein from silk to make virus-sensing gloves, surgical screws that dissolve in your body, and other next-generation biomedical materials

About a mile northwest of Tufts’ Medford/Somerville campus, on the fourth floor of a refurbished woolen factory, there is a shrine to silk. Glass vases filled with silkworm cocoons and washed silk fibers sit artfully on a shelf across from a colorful drawing of the life cycle of Bombyx mori, the domesticated silk moth. Farther in, more cocoons in wall-mounted cases border a large, close-up image of silk fibers, and displays hold dozens of prototypes made from silk, including smart fabrics, biosensors, a helmet that changes color upon impact, and potential replacements for materials like leather, plastic, and particle board.

The only things missing are the silkworms themselves, but Fiorenzo Omenetto, the director of Silklab and the Frank C. Doble Professor of Engineering at Tufts, said they will be arriving soon. The lab is building a terrarium so that visitors can view the animals.
“We’re going to have a celebration of silkworms and moths,” Omenetto said.

Silk has been cultivated and harvested for thousands of years. It is best known for the strong, shimmering fabric that can be woven from its fibers, but it also has a long history of use in medicine to dress injuries and suture wounds. At Silklab, Omenetto and his colleagues are building on silk’s legacy, proving that this ancient fiber could help create the next generation of biomedical materials.

Silk moth caterpillars, known as silkworms, extrude a single sticky strand of silk from their mouths to form cocoons, which are harvested by silk farmers to make silk thread. At its core, silk is a mixture of two proteins: fibroin, which provides the fiber’s structure, and sericin, which binds it together. With a few steps in the lab, Tufts researchers can remove the sericin and dissolve the fibers, turning a dry cocoon into a fibroin-filled liquid.

“Nature builds structural proteins that are very tough and very strong,” Omenetto said. “Your bricks are these fibroin proteins floating in water. From there, you can build whatever you want.”
Starting with shipments of dried cocoons from silk farms, Omenetto and his colleagues have been able to create gels, sponges, clear plastic-like sheets, printable inks, solids that look like amber, dippable coatings, and much more.

“Each of the materials that you make can contain all these different functions, and there’s only 24 hours in a day,” Omenetto said with a laugh. “This is why I don’t sleep.”

Biocompatible and Biodegradable
When Omenetto arrived at Tufts almost two decades ago, his research was focused on lasers and optics—silk wasn’t in the picture. But a chance conversation with David Kaplan, the Stern Family Professor of Engineering and chair of the biomedical engineering department, set him on a new path.

Kaplan, who has been working with silk since the early ’90s, was designing a silk scaffold that would help rebuild a person’s cornea, allowing cells to grow between the layers. He needed a way to ensure that the growing cells would have enough oxygen and showed the small, transparent sheet to Omenetto, who was immediately intrigued by the material. Omenetto was able to use his lab’s lasers to put tiny holes in Kaplan’s silk cornea. More collaborations quickly followed.
“We’ve worked together incessantly since then,” Kaplan said.

One of those lines of research has been finding ways to use silk to help repair and regrow bone, blood vessels, nerves, and other tissue. Silk is biocompatible, meaning it doesn’t cause harm in the body and breaks down in predictable ways. With the right preparation, silk materials can provide necessary strength and structure while the body is healing.

“You can mold and shape silk to whatever you need, and it will hold that volume while the native tissue regrows into the space and the silk material degrades,” Kaplan said. “Eventually it’s 100 percent gone, and you’re back to your normal tissue.”

Some of this work has already been approved for use by the U.S. Food and Drug Administration. A company called Sofregen, which spun out of Kaplan and Omenetto’s research, is using an injectable silk-based gel to repair damaged vocal cords, the tissues that regulate air flow and help us speak.

On their own, sturdy silk structures can keep their size, shape, and function for years before degrading. But in some instances, such as those involving surgical screws and plates intended for use in rapidly growing children, this pace would be too slow. The researchers had to find a way to speed up the time it takes for dense silk biomaterials to break down. They introduced an enzyme that our bodies produce naturally into the silk to hasten the breakdown process. The idea is that the enzyme would sit dry and inactive within the silk device until the structure is installed in a person, then the device would hydrate and activate the enzyme to digest the material more rapidly.

“We can titer in just the right amount of enzyme to make a screw go away in a week, a month, a year,” Kaplan said. “We have control over the process.”

Currently, Kaplan and his lab are working on other small, degradable medical devices that would help cut down on the number of surgeries that patients need. Ear tubes, for example, are often surgically implanted to help alleviate chronic ear infections and then need to be surgically removed. Kaplan and his colleagues have designed silk-based ear tubes that degrade on their own and can even carry antibiotics.

“As someone with a daughter who went through six surgeries on her ear, I know how helpful this could be,” Kaplan said.

Source:

Laura Castañón, Tufts University, Massachusetts USA

offshore windpark Nicholas Doherty, unsplash
17.10.2023

Pyrolysis processes promise sustainable recycling of fiber composites

Wind turbines typically operate for 20 to 30 years before they are undergoing dismantling and recycling. However, the recycling of fiber composites, especially from the thick-walled rotor blade parts, has been inadequate until now. The prevailing methods involve thermal or mechanical recycling. For a sustainable and holistic recycling process, a research consortium led by Fraunhofer IFAM is pooling their expertise to recover the fibers through pyrolysis. Subsequent surface treatment and quality testing of the recyclates allow for them to be used again in industry.

Wind turbines typically operate for 20 to 30 years before they are undergoing dismantling and recycling. However, the recycling of fiber composites, especially from the thick-walled rotor blade parts, has been inadequate until now. The prevailing methods involve thermal or mechanical recycling. For a sustainable and holistic recycling process, a research consortium led by Fraunhofer IFAM is pooling their expertise to recover the fibers through pyrolysis. Subsequent surface treatment and quality testing of the recyclates allow for them to be used again in industry.

Today, the vast majority of wind turbines can already be recycled cleanly. In the case of rotor blades, however, recycling is only just beginning. Due to the 20-year operation period and the installation rates, the blade volume for recycling will be increasing in the coming years and decades. In 2000, for example, around 6,000 wind turbines were erected in Germany, which now need to be fed into a sustainable recycling process. In 2022, about 30,000 onshore and offshore wind turbines with a capacity of 65 gigawatts were in operation in Germany alone.

As wind energy is the most important cornerstone for a climate-neutral power supply, the German government has set itself the goal of further increasing its wind energy capacity by 2030 by installing larger and more modern turbines. Rotor blades will become longer, the proportion of carbon fibers used will continue to increase - and so will the amount of waste. In addition, the existing material mix in rotor blades is expected to increase in the future and precise knowledge of the structure of the components will become even more important for recycling. This underscores the urgency of developing sustainable processing methods, especially for recycling the thick-walled fiber composites in the rotor blades.

Economic and ecological recycling solution for fiber composites on the horizon
Rotor blades of wind turbines currently up for recycling consist of more than 85 percent of glass- and carbon-fiber-reinforced thermosets (GFRP/CFRP). A large proportion of these materials is found in the flange and root area and within the fiber-reinforced straps as thick-walled laminates with a wall thicknesses of up to 150 mm. Research into high-quality material fiber recycling as continuous fibers is of particular importance, not only because of the energy required for carbon fiber production. This is where the project "Pyrolysis of thick-walled fiber composites as a key innovation in the recycling process for wind turbine rotor blades" – "RE SORT" for short – funded by the German Federal Ministry of Economics and Climate Protection comes in. The aim of the project team is the complete recycling by means of pyrolysis.

A prerequisite for high-quality recycling of fiber composites is the separation of the fibers from the mostly thermoset matrix. Although pyrolysis is a suitable process for this purpose, it has not yet gained widespread adoption. Within the project, the project partners are therefore investigating and developing pyrolysis technologies that make the recycling of thick-walled fiber composite structures economically feasible and are technically different from the recycling processes commonly used for fiber composites today. Both quasi-continuous batch and microwave pyrolysis are being considered.

Batch pyrolysis, which is being developed within the project, is a pyrolysis process in which the thermoset matrix of thick fiber composite components is slowly decomposed into oily and especially gaseous hydrocarbon compounds by external heating. In microwave pyrolysis, energy is supplied by the absorption of microwave radiation, resulting in internal rapid heat generation. Quasi-continuous batch pyrolysis as well as microwave pyrolysis allow the separation of pyrolysis gases or oils. The planned continuous microwave pyrolysis also allows for the fibers to be preserved and reused in their full length.

How the circular economy succeeds - holistic utilization of the recycled products obtained
In the next step, the surfaces of the recovered recycled fibers are prepared by means of atmospheric plasmas and wet-chemical coatings to ensure their suitability for reuse in industrial applications. Finally, strength tests can be used to decide whether the recycled fibers will be used again in the wind energy industry or, for example, in the automotive or sporting goods sectors.

The pyrolysis oils and pyrolysis gases obtained in batch and microwave pyrolysis are evaluated with respect to their usability as raw materials for polymer synthesis (pyrolysis oils) or as energy sources for energy use in combined heat and power (CHP) plants (pyrolysis gases).

Both quasi-continuous batch pyrolysis and continuous-flow microwave pyrolysis promise economical operation and a significant reduction in the environmental footprint of wind energy. Therefore, the chances for a technical implementation and utilization of the project results are very good, so that this project can make a decisive contribution to the achievement of the sustainability and climate goals of the German Federal Government.

Source:

Fraunhofer-Institut für Fertigungstechnik und Angewandte Materialforschung IFAM

A quick check with a smartphone, and the integrated spectrum analyzer recognizes the fabric the garment is made from. Photo: © Fraunhofer IPMS. A quick check with a smartphone, and the integrated spectrum analyzer recognizes the fabric the garment is made from.
10.10.2023

Checking clothing using a smartphone, AI and infrared spectroscopy

Researchers at Fraunhofer have developed an ultra-compact near-infrared spectrometer suitable for recognizing and analyzing textiles. Mixed fabrics can also be reliably identified through the combination of imaging, special AI (artificial intelligence) algorithms and spectroscopy. The technology could be used to optimize recycling old clothing, so old apparel could be sorted according to type. A highly miniaturized version of the system can even fit into a smartphone. This could lead to a host of new applications for end-users in everyday life — from checking clothes when out shopping to detecting counterfeits.

Researchers at Fraunhofer have developed an ultra-compact near-infrared spectrometer suitable for recognizing and analyzing textiles. Mixed fabrics can also be reliably identified through the combination of imaging, special AI (artificial intelligence) algorithms and spectroscopy. The technology could be used to optimize recycling old clothing, so old apparel could be sorted according to type. A highly miniaturized version of the system can even fit into a smartphone. This could lead to a host of new applications for end-users in everyday life — from checking clothes when out shopping to detecting counterfeits.

Infrared spectrometers are powerful measuring instruments when it comes to non-destructive analysis of organic materials. The Fraunhofer Institute for Photonic Microsystems IPMS in Dresden has recently developed a spectral analyzer system that recognizes and analyzes textile fabrics. The system can also reliably recognize mixed fabrics. Possible applications range from checking fabrics when out shopping to cleaning garments correctly, and even sustainable, sorted recycling. The spectrometer is so tiny, it can be integrated into a smartphone.

Researchers at Fraunhofer rely on near-infrared (NIR) spectroscopy to achieve the required reliability and accuracy when identifying textiles. The system works for wavelengths between 950 and 1900 nanometers, which is close to the visible spectrum. Advantages of near-infrared technology include being easy to use and having a wide range of applications. “We combine NIR spectroscopy with imaging and AI to achieve higher accuracy when recognizing and analyzing objects,” explains Dr. Heinrich Grüger, research scientist in the Sensoric Micromodules department at Fraunhofer IPMS.

How textile analysis works
Firstly, a conventional camera module captures an image of the garment. The AI selects a specific point from the fabric’s image data to be examined by the spectral analyzer module. Light reflected from the fabric is captured by the spectrometer module. There, it passes through an entrance slit, is transformed into parallel light beams using a collimating mirror and projected onto a grating using a scanning mirror. Depending on the angle of incidence and exit, the grating splits the light beams into different wavelengths. Light reflected from the grating is directed by the scanner mirror to a detector which captures the light as an electrical signal. An A/D converter then digitizes these signals, which are subsequently analyzed in the signal processor. The resulting spectrometric profile for the textile fabric reveals which fibers it is made from by comparing to a reference database.“ The optical resolution is 10 nanometers. This high resolution means the NIR spectrometer can also use AI to identify mixed fabrics such as items of clothing made from polyester and cotton,” says Grüger. Measuring just 10 mm × 10 mm and being 6.5 mm thick, the system is so compact it could easily be integrated into a standard smartphone.

Recycling old clothing
Grüger sees an important application for the AI-controlled spectrometer when it comes to recycling. According to the Federal Statistical Office of Germany, approximately 176,200 tons of textile and clothing waste was collected from private homes in Germany in 2021. NIR spectroscopy could improve recycling efficiency and reduce the mountain of old clothing. This would enable companies that recycle old clothing to sort it more efficiently and faster. Textiles that are still in one piece, for instance, go to the second-hand trade. Damaged textiles are sorted for recycling, and the fibers they are made from, such as linen, silk, cotton or lyocell, can be reused. Severely soiled textiles would be incinerated or processed into insulation mats, for example. Spectroscopic identifies and sorts textiles more accurately and much faster than a human can.

If NIR spectroscopy was to be integrated into a smartphone, end-users might also benefit from the Fraunhofer institute’s technology. When buying clothes, a quick check with a smartphone reveals whether that expensive silk scarf is genuinely made from silk, or whether that exclusive dress from the fashion label is not instead a counterfeit, exposed through an alternative mix of fabrics. And should the label with the cleaning instructions no longer be legible, the smartphone has a textile scanner to identify the fabric and so determine the appropriate wash cycle.

Food check and dermatology
Researchers at Fraunhofer IPMS can even envisage applications beyond the textile industry. Smartphones fitted with spectrometers might be used to provide information about the quality of groceries such as fruit and vegetables when out shopping. The technology might conceivably also be used to examine skin. A quick scan with the cell phone spectrometer could identify particularly dry or greasy patches. Perhaps applications in medical diagnostics might even be conceivable — examining patches of skin where a melanoma is suspected, for example — but this would need professional involvement too.

Source:

Fraunhofer Institute for Photonic Microsystems

Researchers made shape-changing fibers by encapsulating a balloon-like tube in a braided textile sheath. (c) : Muh Amdadul Hoque. Researchers made shape-changing fibers by encapsulating a balloon-like tube in a braided textile sheath.
27.09.2023

Artificial Muscle Fibers Could Serve as Cell Scaffolds

In two new studies, North Carolina State University researchers designed and tested a series of textile fibers that can change shape and generate force like a muscle. In the first study, the researchers focused on the materials’ influence on the artificial muscles’ strength and contraction length. The findings could help researchers tailor the fibers for different applications.

In the second, proof-of-concept study, the researchers tested their fibers as scaffolds for live cells. Their findings suggest the fibers – known as “fiber robots” – could potentially be used to develop 3D models of living, moving systems in the human body.

In two new studies, North Carolina State University researchers designed and tested a series of textile fibers that can change shape and generate force like a muscle. In the first study, the researchers focused on the materials’ influence on the artificial muscles’ strength and contraction length. The findings could help researchers tailor the fibers for different applications.

In the second, proof-of-concept study, the researchers tested their fibers as scaffolds for live cells. Their findings suggest the fibers – known as “fiber robots” – could potentially be used to develop 3D models of living, moving systems in the human body.

“We found that our fiber robot is a very suitable scaffold for the cells, and we can alter the frequency and contraction ratio to create a more suitable environment for cells,” said Muh Amdadul Hoque, graduate student in textile engineering, chemistry and science at NC State. “These were proof-of concept studies; ultimately, our goal is to see if we can study these fibers as a scaffold for stem cells, or use them to develop artificial organs in future studies.”
 
Researchers made the shape-changing fibers by encapsulating a balloon-like tube, made of a material similar to rubber, in a braided textile sheath. Inflating the interior balloon with an air pump makes the braided sheath expand, causing it to shorten.

The researchers measured the force and contraction rates of fibers made from different materials in order to understand the relationship between material and performance. They found that stronger, larger diameter yarns generated a stronger contraction force. In addition, they found that the material used to make the balloon impacted the magnitude of the contraction and generated force.
 
“We found that we could tailor the material properties to the required performance of the device,” said Xiaomeng Fang, assistant professor of textile engineering, chemistry and science at NC State. “We also found that we can make this device small enough so we can potentially use it in fabric formation and other textile applications, including in wearables and assistive devices.”
 
In a follow-up study, researchers evaluated whether they could use the shape-changing fibers as a scaffold for fibroblasts, a cell type found in connective tissues that help support other tissues or organs.

“The idea with stretching is to mimic the dynamic nature of how your body moves,” said Jessica Gluck, assistant professor of textile engineering, chemistry and science at NC State, and a study co-author.

They studied the cells’ response to the motion of the shape-changing fibers, and to different materials used in the fibers’ construction. They found the cells were able to cover and even penetrate the fiber robot’s braiding sheath. However, they saw decreases in the cells’ metabolic activity when the fiber robot’s contraction extended beyond a certain level, compared to a device made of the same material that they kept stationary.

The researchers are interested in building on the findings to see if they could use the fibers as a 3D biological model, and to investigate whether movement would impact cell differentiation. They said their model would be an advance over other existing experimental models that have been developed to show cellular response to stretching and other motion, since they can only move in two dimensions.
 
“Typically, if you want to add stretch or strain on cells, you would put them onto a plastic dish, and stretch them in one or two directions,” Gluck said. “In this study, we were able to show that in this 3D dynamic culture, the cells can survive for up to 72 hours.

“This is particularly useful for stem cells,” Gluck added. “What we could do in the future is look at what could happen at the cellular level with mechanical stress on the cells. You could look at muscle cells and see how they’re developing, or see how the mechanical action would help differentiate the cells.”

The study, “Effect of Material Properties on Fiber-Shaped Pneumatic Actuators Performance” was published in Actuators on March 18. Emily Petersen was a co-author. The study was funded by start-up funding awarded to Fang from the Department of Textile Engineering, Chemistry and Science at NC State.

The study, “Development of a Pneumatic-Driven Fiber-Shaped Robot Scaffold for Use as a Complex 3D Dynamic Culture System” was published online in Biomimetics on April 21. In addition to Gluck, Hoque and Fang, co-authors included Nasif Mahmood, Kiran M. Ali, Eelya Sefat, Yihan Huang, Emily Petersen and Shane Harrington. The study was funded by the NC State Wilson College of Textiles, the Department of Textile Engineering, Chemistry and Science and the Wilson College of Textiles Research Opportunity Seed Fund Program.

Source:

North Carolina State University, Laura Oleniacz. Übersetzung Textination

Photo unsplash.com
05.09.2023

Ananas Anam and TENCEL™ collaborate with Calvin Klein

The search for better, planet-friendly footwear material reveals a solution in one unlikely ingredient: pineapple leaves. This unique textile ingredient is the recent focus of the latest footwear design collaboration between Ananas Anam, TENCEL™ and Calvin Klein, launching Calvin Klein’s first-ever trainer featuring a knitted upper made of PIÑAYARN® blended with TENCEL™ Lyocell fibers.

Known as “The Sustainable Knit Trainer”, the trainers are a timeless closet staple, available in classic colors such as black and off-white and etched with the signature Calvin Klein logo. The PIÑAYARN® knit upper, made of 70% TENCEL™ Lyocell and 30% Anam PALF™ pineapple leaf fiber, is both from botanic origin and bio-based.

The search for better, planet-friendly footwear material reveals a solution in one unlikely ingredient: pineapple leaves. This unique textile ingredient is the recent focus of the latest footwear design collaboration between Ananas Anam, TENCEL™ and Calvin Klein, launching Calvin Klein’s first-ever trainer featuring a knitted upper made of PIÑAYARN® blended with TENCEL™ Lyocell fibers.

Known as “The Sustainable Knit Trainer”, the trainers are a timeless closet staple, available in classic colors such as black and off-white and etched with the signature Calvin Klein logo. The PIÑAYARN® knit upper, made of 70% TENCEL™ Lyocell and 30% Anam PALF™ pineapple leaf fiber, is both from botanic origin and bio-based.

As the fashion sector has begun to realize the negative environmental effects of synthetic materials, a lot of brands have turned towards plant-based materials such as PIÑAYARN®. Using a low-impact manufacturing process, PIÑAYARN® is derived from pineapple leaf waste and involves a water-free spinning process. The addition of TENCEL™ Lyocell, a fiber made from wood pulp obtained from responsibly managed forests and produced using a solvent spinning process that recycles both the solvent and water at a recovery rate of more than 99%, offers full traceability of the TENCEL™ fiber in the final blended yarn.

Melissa Braithwaite, PIÑAYARN® Product Development Manager at Ananas Anam said “The inspiration for PIÑAYARN® came from the need to provide the textile industry with an alternative to overused, often polluting, conventional fibers, such as cotton or polyester. We have an abundance of available raw material within our business, and broadening our product offering means we can valorize more waste, increasing our positive impact on the environment and society.”

Indeed, as the consumer demand for more eco-responsible textile products and footwear grows, so too has the popularity of wood-based fibers as a material alternative. Ananas Anam and TENCEL™’s collaboration with Calvin Klein has been a success in that the physical characteristics and planet-conscious benefits of both PIÑAYARN® and TENCEL™ fibers complement each other perfectly, creating a blended material that is soft and usable for various woven and knitted applications.

For material developers like Ananas Anam seeking the ideal fiber blend partner to create PIÑAYARN®, TENCEL™ Lyocellfibers are celebrated for their versatility and ability to be blended with a wide range of textiles such as hemp, linen and of course Anam PALF™ pineapple leaf fiber, to enhance the aesthetics, performance and functionality of fabrics. Additionally, beyond being used in shoe uppers, TENCEL™ Lyocell fibers can be used in every part of the shoe including the upper fabric, lining, insoles, padding, laces, zipper and sewing thread. TENCEL™ Lyocell can also be used in powder form for use in the outsoles of shoes.

“We are extremely excited about this collaboration with Ananas Anam for the launch of The Sustainable Knit Trainer by Calvin Klein, an eco-responsible and planet-friendly shoe for conscious consumers. This partnership is the perfect example of our commitment to provide education and expertise to support anyone who chooses to improve the environmental and social credentials of their products by using more responsible materials,” said Nicole Schram, Global Business Development Manager at Lenzing.

Source:

Lenzing AG

(c) Institut auf dem Rosenberg
01.09.2023

‘Blue Nomad’ - Floating Into the Future with Flax Fibres

As humanity grapples with climate change and rising sea levels, our collective imagination is more critical than ever. In light of this, bcomp presents the phenomenal work initiated by the students from Institut auf dem Rosenberg in St. Gallen and SAGA Space Architects. They’ve developed an extraordinary solution to address the environmental challenges we face: the ‘Blue Nomad’ floating habitat.

‘Blue Nomad’ is a solar-powered home designed for comfortable living on the ocean. It symbolises a future where we must explore and adapt to the changing earth’s environment. Drawing inspiration from the first Polynesian nomadic settlements and equipped with solar panels for self-sustainability, the habitat promotes a vision of living and traveling on water.

As humanity grapples with climate change and rising sea levels, our collective imagination is more critical than ever. In light of this, bcomp presents the phenomenal work initiated by the students from Institut auf dem Rosenberg in St. Gallen and SAGA Space Architects. They’ve developed an extraordinary solution to address the environmental challenges we face: the ‘Blue Nomad’ floating habitat.

‘Blue Nomad’ is a solar-powered home designed for comfortable living on the ocean. It symbolises a future where we must explore and adapt to the changing earth’s environment. Drawing inspiration from the first Polynesian nomadic settlements and equipped with solar panels for self-sustainability, the habitat promotes a vision of living and traveling on water.

bcomp is particularly excited about the project as the scaled model that was exhibited in London and Monaco prominently features their very own ampliTex™ flax fibres. A plan of building an actual prototype of the floating home is being developed by Institut auf dem Rosenberg and SAGA. It could be made from a structurally optimised weave of flax fibre, showcasing the future of organic and regenerative high-performance materials replacing conventional synthetic and fossil-based technologies. As a company, bcomp is proud to provide sustainable material solutions, and seeing their flax fibres used in such an innovative and meaningful project is both humbling and inspiring.

‘Blue Nomad’ isn’t just a solitary habitat, but a concept for a new kind of community. Imagined as modular blocks, these habitats can form larger communities and oceanic farms, allowing inhabitants to share resources while moving from one oceanic farm to the next. It’s a striking vision of a future where the lines between land and water blur, and sustainability and community building lie at the heart of human settlements.

But this vision is not just theoretical. Plans are being made for a maiden voyage of ‘Blue Nomad’ across Europe, powered purely by solar energy, promoting ocean sustainability, climatology, and future nomadism.

This project serves as a powerful reminder of what can be achieved when education, innovative design, and sustainability are united. The ‘Blue Nomad’ represents the future we envision – a future where sustainable materials play a crucial role in safeguarding our planet.

The ‘Blue Nomad’ project was exhibited at the London Design Biennale 2023 as well as the Monaco Energy Boat Challenge where it was captivating visitors and garnering significant attention from the public.    

Source:

Bcomp

Photo: zephylwer0, Pixabay
29.08.2023

Taming a fire: A new way with nanoscale material

High-temperature flames are used to create a wide variety of materials – but once you start a fire, it can be difficult to control how the flame interacts with the material you are trying to process. Researchers have now developed a technique that utilizes a molecule-thin protective layer to control how the flame’s heat interacts with the material – taming the fire and allowing users to finely tune the characteristics of the processed material.

“Fire is a valuable engineering tool – after all, a blast furnace is only an intense fire,” says Martin Thuo, corresponding author of a paper on the work and a professor of materials science and engineering at North Carolina State University. “However, once you start a fire, you often have little control over how it behaves.

High-temperature flames are used to create a wide variety of materials – but once you start a fire, it can be difficult to control how the flame interacts with the material you are trying to process. Researchers have now developed a technique that utilizes a molecule-thin protective layer to control how the flame’s heat interacts with the material – taming the fire and allowing users to finely tune the characteristics of the processed material.

“Fire is a valuable engineering tool – after all, a blast furnace is only an intense fire,” says Martin Thuo, corresponding author of a paper on the work and a professor of materials science and engineering at North Carolina State University. “However, once you start a fire, you often have little control over how it behaves.

“Our technique, which we call inverse thermal degradation (ITD), employs a nanoscale thin film over a targeted material. The thin film changes in response to the heat of the fire, and regulates the amount of oxygen that can access the material. That means we can control the rate at which the material heats up – which, in turn, influences the chemical reactions taking place within the material. Basically, we can fine-tune how and where the fire changes the material.”

Here’s how ITD works. You start out with your target material, such as a cellulose fiber. That fiber is then coated with a nanometer thick layer of molecules. The coated fibers are then exposed to an intense flame. The outer surface of the molecules combusts easily, raising the temperature in the immediate vicinity. But the inner surface of the molecular coating chemically changes, creating an even thinner layer of glass around the cellulose fibers. This glass limits the amount of oxygen that can access the fibers, preventing the cellulose from bursting into flames. Instead, the fibers smolder – burning slowly, from the inside out.

“Without the ITD’s protective layer, applying flame to cellulose fibers would just result in ash,” Thuo says. “With the ITD’s protective layer, you end up with carbon tubes.

“Without the ITD’s protective layer, applying flame to cellulose fibers would just result in ash,” Thuo says. “With the ITD’s protective layer, you end up with carbon tubes.

“We can engineer the protective layer in order to tune the amount of oxygen that reaches the target material. And we can engineer the target material in order to produce desirable characteristics.”

The researchers conducted proof-of-concept demonstrations with cellulose fibers to produce microscale carbon tubes.

The researchers could control the thickness of the carbon tube walls by controlling the size of the cellulose fibers they started with; by introducing various salts to the fibers (which further controls the rate of burning); and by varying the amount of oxygen that passes through the protective layer.

“We have several applications in mind already, which we will be addressing in future studies,” Thuo says. “We’re also open to working with the private sector to explore various practical uses, such as developing engineered carbon tubes for oil-water separation – which would be useful for both industrial applications and environmental remediation.”

The paper, “Spatially Directed Pyrolysis via Thermally Morphing Surface Adducts,” is published in the journal Angewandte Chemie. Co-authors are Dhanush Jamadgni and Alana Pauls, Ph.D. students at NC State; Julia Chang and Andrew Martin, postdoctoral researchers at NC State; Chuanshen Du, Paul Gregory, Rick Dorn and Aaron Rossini of Iowa State University; and E. Johan Foster at the University of British Columbia.

Source:

North Carolina State University, Matt Shipman

Photo: Claude Huniade
11.07.2023

Ionofibres a new track for smart and functional textiles

Electronically conductive fibres are already in use in smart textiles, but in a recently published research article, ionically conductive fibres have proven to be of increasing interest. The so-called ionofibres achieve higher flexibility and durability and match the type of conduction our body uses. In the future, they may be used for such items as textile batteries, textile displays, and textile muscles.

The research project is being carried out by doctoral student Claude Huniade at the University of Borås and is a track within a larger project, Weafing, the goal of which is to develop novel, unprecedented garments for haptic stimulation comprising flexible and wearable textile actuators and sensors, including control electronics, as a new type of textile-based large area electronics.

WEAFING stands for Wearable Electroactive Fabrics Integrated in Garments. It started 1 January 2019 and ended 30 June 2023.

Electronically conductive fibres are already in use in smart textiles, but in a recently published research article, ionically conductive fibres have proven to be of increasing interest. The so-called ionofibres achieve higher flexibility and durability and match the type of conduction our body uses. In the future, they may be used for such items as textile batteries, textile displays, and textile muscles.

The research project is being carried out by doctoral student Claude Huniade at the University of Borås and is a track within a larger project, Weafing, the goal of which is to develop novel, unprecedented garments for haptic stimulation comprising flexible and wearable textile actuators and sensors, including control electronics, as a new type of textile-based large area electronics.

WEAFING stands for Wearable Electroactive Fabrics Integrated in Garments. It started 1 January 2019 and ended 30 June 2023.

These wearables are based on a new kind of textile muscles which yarns are coated with electromechanically active polymers and contract when a low voltage is applied. Textile muscles offer a completely novel and very different quality of haptic sensation, accessing also receptors of our tactile sensory system that do not react on vibration, but on soft pressure or stroke.

Furthermore, being textile materials, they offer a new way of designing and fabricating wearable haptics and can be seamlessly integrated into fabrics and garments. For these novel form of textile muscles, a huge range of possible applications in haptics is foreseen: for ergonomics, movement coaching in sports, or wellness, for enhancement of virtual or augmented reality applications in gaming or for training purposes, for inclusion of visually handicapped people by providing them information about their environment, for stress reduction or social communication, adaptive furniture, automotive industry and many more.

In Claude Huniade’s project, the goal is to produce conductive yarns without conductive metals.

"My research is about producing electrically conductive textile fibres, and ultimately yarns, by coating non-metals sustainably on commercial yarns. The biggest challenge is in the balance between keeping the textile properties and adding the conductive feature," said Claude Huniade.

Currenty, the uniqueness of his research leans towards the strategies employed when coating. These strategies expand to the processes and the materials used.

Uses ionic liquid
One of the tracks he investigates is about a new kind of material as textile coating, ionic liquids in combination with commercial textile fibres. Just like salt water, they conduct electricity but without water. Ionic liquid is a more stable electrolyte than salt water as nothing evaporates.

"The processable aspect is an important requirement since textile manufacturing can be harsh on textile fibres, especially when upscaling their use. The fibres can also be manufactured into woven or knitted without damaging them mechanically while retaining their conductivity. Surprisingly, they were even smoother to process into fabrics than the commercial yarns they are made from," explained Claude Huniade.

Ionofibres could be used as sensors since ionic liquids are sensitive to their environment. For example, humidity change can be sensed by the ionofibers, but also any stretch or pressure they are subjected to.

"Ionofibres could truly shine when they are combined with other materials or devices that require electrolytes. Ionofibres enable certain phenomena currently limited to happen in liquids to be feasible in air in a lightweight fashion. The applications are multiple and unique, for example for textile batteries, textile displays or textile muscles," said Claude Huniade.

Needs further research
Yet more research is needed to combine the ionofibres with other functional fibres and to produce the unique textile devices.

How do they stand out compared to common electronically conductive fibres?

"In comparison to electronically conductive fibres, ionofibers are different in how they conduct electricity. They are less conductive, but they bring other properties that electronically conductive fibers often lack. Ionofibres achieve higher flexibility and durability and match the type of conduction that our body uses. They actually match better than electronically conductive fibres with how electricity is present in nature," he concluded.

Source:

University of Borås

Thread-like pumps can be woven into clothes (c) LMTS EPFL
27.06.2023

Thread-like pumps can be woven into clothes

Ecole Polytechnique Fédérale de Lausanne (EPFL) researchers have developed fiber-like pumps that allow high-pressure fluidic circuits to be woven into textiles without an external pump. Soft supportive exoskeletons, thermoregulatory clothing, and immersive haptics can therefore be powered from pumps sewn into the fabric of the devices themselves.

Many fluid-based wearable assistive technologies today require a large and noisy pump that is impractical – if not impossible – to integrate into clothing. This leads to a contradiction: wearable devices are routinely tethered to unearable pumps. Now, researchers at the Soft Transducers Laboratory (LMTS) in the School of Engineering have developed an elegantly simple solution to this dilemma.

Ecole Polytechnique Fédérale de Lausanne (EPFL) researchers have developed fiber-like pumps that allow high-pressure fluidic circuits to be woven into textiles without an external pump. Soft supportive exoskeletons, thermoregulatory clothing, and immersive haptics can therefore be powered from pumps sewn into the fabric of the devices themselves.

Many fluid-based wearable assistive technologies today require a large and noisy pump that is impractical – if not impossible – to integrate into clothing. This leads to a contradiction: wearable devices are routinely tethered to unearable pumps. Now, researchers at the Soft Transducers Laboratory (LMTS) in the School of Engineering have developed an elegantly simple solution to this dilemma.

“We present the world’s first pump in the form of a fiber; in essence, tubing that generates its own pressure and flow rate,” says LMTS head Herbert Shea. “Now, we can sew our fiber pumps directly into textiles and clothing, leaving conventional pumps behind.” The research has been published in the journal Science.

Lightweight, powerful…and washable
Shea’s lab has a history of forward-thinking fluidics. In 2019, they produced the world’s first stretchable pump.

“This work builds on our previous generation of soft pump,” says Michael Smith, an LMTS post-doctoral researcher and lead author of the study. “The fiber format allows us to make lighter, more powerful pumps that are inherently more compat-ible with wearable technology.”

The LMTS fiber pumps use a principle called charge injection electrohydrodynamics (EHD) to generate a fluid flow without any moving parts. Two helical electrodes embedded in the pump wall ionize and accelerate molecules of a special non-conductive liquid. The ion movement and electrode shape generate a net forward fluid flow, resulting in silent, vibration-free operation, and requiring just a palm-sized power supply and battery.

To achieve the pump’s unique structure, the researchers developed a novel fabrication technique that involves twisting copper wires and polyurethane threads together around a steel rod, and then fusing them with heat. After the rod is removed, the 2 mm fibers can be integrated into textiles using standard weaving and sewing techniques.

The pump’s simple design has a number of advantages. The materials required are cheap and readily available, and the manufacturing process can be easily scaled up. Because the amount of pressure generated by the pump is directly linked to its length, the tubes can be cut to match the application, optimizing performance while minimizing weight. The robust design can also be washed with conventional detergents.

From exoskeletons to virtual reality
The authors have already demonstrated how these fiber pumps can be used in new and exciting wearable technologies. For example, they can circulate hot and cold fluid through garments for those working in extreme temperature environments or in a therapeutic setting to help manage inflammation; and even for those looking to optimize athletic performance.

“These applications require long lengths of tubing anyway, and in our case, the tubing is the pump. This means we can make very simple and lightweight fluidic circuits that are convenient and comfortable to wear,” Smith says.

The study also describes artificial muscles made from fabric and embedded fiber pumps, which could be used to power soft exoskeletons to help patients move and walk.

The pump could even bring a new dimension to the world of virtual reality by simulating the sensation of temperature. In this case, users wear a glove with pumps filled with hot or cold liquid, allowing them to feel temperature changes in response to contact with a virtual object.

Pumped up for the future
The researchers are already looking to improve the performance of their device. “The pumps already perform well, and we’re confident that with more work, we can continue to make improvements in areas like efficiency and lifetime,” says Smith. Work has already started on scaling up the production of the fiber pumps, and the LMTS also has plans to embed them into more complex wearable devices.

“We believe that this innovation is a game-changer for wearable technology,” Shea says.

More information:
EPFL Fibers exoskeleton wearables
Source:

Celia Luterbacher, School of Engineering | STI

(c) Fraunhofer IBMT
10.05.2023

Using textile electrodes to stop muscle tremor

Scientists at the Fraunhofer Institute for Biomedical Engineering IBMT have been working with international partners to develop a technology platform to help relieve the symptoms of muscle tremors. Tiny biocompatible electrodes in the muscles, combined with external electrodes and controllers, form an intelligent network of sensors and actuators to detect muscle signals and provide electrical stimuli as needed. Together with exoskeletons, the technology could also help people with spinal cord injuries.

Scientists at the Fraunhofer Institute for Biomedical Engineering IBMT have been working with international partners to develop a technology platform to help relieve the symptoms of muscle tremors. Tiny biocompatible electrodes in the muscles, combined with external electrodes and controllers, form an intelligent network of sensors and actuators to detect muscle signals and provide electrical stimuli as needed. Together with exoskeletons, the technology could also help people with spinal cord injuries.

A compact controller on a belt or under a jacket, a couple of discreet textile electrodes on the arms and legs, and electrodes three centimeters long and barely a millimeter thin in the muscle are all it will take to help people with tremor disorders in the future. Whenever muscle tremors start, the system sends electrical stimuli to the muscles; these stimuli are registered by the nervous system. The nervous system then stops sending interfering signals to the muscles, which settle down again. That is the basic idea behind the technology that scientists from Fraunhofer IBMT have been working on together with project partners by developing, manufacturing, integrating and experimentally testing a set of intramuscular and external electrodes and associated controllers.

The scientists have already made some concrete achievements. “We have managed to reduce muscle tremors significantly in trials with patients,” explains Andreas Schneider-Ickert, project manager for active implants and innovation manager.

The system is part of the EU-funded joint project “EXTEND.” A total of nine project partners from five different countries are working together to develop a versatile platform of distributed neural interfaces. The technology will be able to help people with neuromuscular disorders, such as tremors, or symptoms of paralysis. Even people with spinal cord injuries could benefit from this. The technology uses external controllers to link the implanted electrodes into an intelligent network. The components communicate with each other wirelessly, exchange data, detect muscle signals and send targeted stimuli into the muscles. Implanted systems are already being used medically to provide stimulation, but the current methods require complex surgical operations that are considerably stressful for patients.

Implants for the human-machine interface
A key element of EXTEND is the implants, which are made from biocompatible platinum-iridium and silicone and are injected into the muscle through a catheter. Just three centimeters long and barely a millimeter in diameter, the tiny implant has an electrode at each end that functions as either a sensor or an actuator. External electrodes sewn into a textile ribbon supply the module with energy. This sends pulsed alternating current through the muscle tissue to the implant. “What’s innovative about this is not only the intelligent interplay between control electronics, sensors and actuators, but also the principle of modulating the alternating current to transmit data,” explains Schneider-Ickert.

Once it has been implanted and started, the sensors register the first signs of muscle tremors and pass the information on to the external components. The controller evaluates the data and sends signals through the textile electrodes to stimulate the muscle. This closes a control circuit of intelligently networked sensor and actuator components that counteracts the tremor.

The stimulus signal is not strong enough to trigger a muscle contraction directly. It is the nervous system that plays the decisive role here. This registers the stimulation in the muscle tissue and responds by stopping the commands that trigger the muscle tremor. At least that is the theory — the finer details of the relationship between tremors and signals from the nervous system are yet to be researched. “In clinical trials, however, our method is working astonishingly well. Initial trials have shown that providing the patient with stimuli for one or two hours is enough to reduce tremor symptoms for a longer period of time,” says Schneider-Ickert.

Since tremors often occur in both arms and both legs, implants can be injected and external textile electrodes placed in all the affected muscle groups. This creates a distributed sensor network. The controllers can keep track of all the implanted and external electrodes at the same time and control them in coordination with each other. All this happens in real time, with the person experiencing no delay at all.

The technology being developed in the EXTEND joint project is just as functional as conventional implant systems, but minimally invasive and therefore easier to accept and better for everyday use. The basic concept originates from a Spanish project partner. Based in this concept, the researchers at Fraunhofer IBMT designed the electrodes and implantable components and produced and integrated them in the in-house cleanroom. The scientists have 25 years of expertise in neuroprosthetics and active implants.

Exoskeletons to prevent paraplegia
For tremor patients, EXTEND brings them the hope that their symptoms can be alleviated considerably. However, the technology platform could also help people with spinal cord injuries thanks to motorized exoskeletons. This is a possible because, in cases of paralysis, the nerve fibers are often not completely cut off. They can still transmit stimuli from the brain, albeit very weakly. The sensors register the activity and transmit it to the controller, which analyzes all the signals, works out what movement the person wants to perform and activates exactly the right prostheses to support the muscles in executing the movement.

Following initial successful tests, the concepts and technologies used in EXTEND have been steadily developed, miniaturized, optimized and subjected to further implementation studies. As a result, the project has now been completed with a successful proof of concept of the miniaturized full system in humans. Fraunhofer IBMT will use the knowledge gained from EXTEND to further develop its expertise in the field of neuromuscular and neural interfaces.

Source:

Fraunhofer Institute for Biomedical Engineering IBMT

Fibroblasts (connective tissue cells) on the electrospun Renacer® membrane under the confocal microscope (red: cytoskeleton of the cells, blue: cell nuclei). (c) Fraunhofer-Institut für Silicatforschung ISC
02.05.2023

Bioresorbable membrane: depot for active substances

Fraunhofer researchers have succeeded in using the bioresorbable silica gel Renacer® to produce an electrospun membrane that is neither cytotoxic to cells nor genotoxic. This model mimics fibrous structures found in connective tissue and is therefore particularly suitable for regenerative applications, such as for improved wound healing.
 
The treatment of large as well as internal wounds is challenging and can be a very lengthy process. Researchers at the Fraunhofer Institute for Silicate Research ISC and the Fraunhofer Institute for Toxicology and Experimental Medicine ITEM have developed a bioresorbable membrane for this use. This membrane supports wound healing and biodegrades completely in the body to a natural substance.

Fraunhofer researchers have succeeded in using the bioresorbable silica gel Renacer® to produce an electrospun membrane that is neither cytotoxic to cells nor genotoxic. This model mimics fibrous structures found in connective tissue and is therefore particularly suitable for regenerative applications, such as for improved wound healing.
 
The treatment of large as well as internal wounds is challenging and can be a very lengthy process. Researchers at the Fraunhofer Institute for Silicate Research ISC and the Fraunhofer Institute for Toxicology and Experimental Medicine ITEM have developed a bioresorbable membrane for this use. This membrane supports wound healing and biodegrades completely in the body to a natural substance.

The basis for the novel membrane is a fiber fleece developed at Fraunhofer ISC. This fleece has already been approved as a medical device to support the regeneration of chronic wounds, such as the diabetic foot. During the healing process, the material dissolves completely within six to eight weeks. Using the electrospinning method, the researchers have now managed to reduce the 50-micrometer fiber diameter by a factor of more than 50, resulting in fibers with diameters of less than one micrometer (µm). This made it possible to spin a silica gel sol into an open-meshed silica gel membrane consisting of fibers with a diameter of about one µm. In some cases, the diameters achieved were as small as 100 nanometers. “These fiber systems imitate the extracellular matrix, the fiber structures found in connective tissue, in the body and are very well tolerated by human cells for tissue regeneration. They cause no foreign body reactions and no internal scarring. The innovative silica gel membrane releases only one degradation product, ortho-silicic acid. This has a regenerative effect on the tissue and promotes the closing of wounds,” explains Dr. Bastian Christ, a scientist at the Fraunhofer ISC in Würzburg. Together with his colleagues, he was in charge of the synthesis and processing of the material.
 
“While the original fiber fleece of 50 µm thick fibers is inserted into a chronic wound from the outside, the thinner fiber fleece is also suitable for internal use. Theoretically, it could be placed onto the filler material used for bone defects in the jaw to accelerate wound healing,” is how Dr. Christina Ziemann, research scientist at Fraunhofer ITEM responsible for the biological evaluation of the material, describes one of numerous possible applications. “In principle, the membrane can be glued in the body with biodegradable adhesives.

Material is neither cyto- nor genotoxic
Using a confocal microscope, a special light microscope, it was possible to show that the small-meshed membrane, which serves as a demonstrator, exhibits a barrier function. This prevents the passage of connective tissue cells for a period of at least seven days without interfering with cell proliferation. In addition, the membrane is resorbable, is not cyto- or genotoxic and thus causes no direct damage to tissue or DNA.

Fiber diameter and mesh size influence the behavior of the cells
A thin fiber diameter of 100 nanometers with thin meshes was chosen for use as an adhesion barrier to prevent postoperative adhesions and scarring. With this configuration, only nutrients could pass through the fiber fleece, but connective tissue cells could not. With a fiber diameter of one micrometer and correspondingly wider meshes, on the other hand, the cells grow into the fiber mesh, proliferate there and have a regenerating effect on the surrounding tissue. “By adjusting the material properties, such as fiber diameter and mesh size, it is possible to influence the behavior of the cells as desired,” says Christ. The equipment required for spinning the fibers is designed at Fraunhofer ISC to meet application and specific customer requirements. The shape and size of the fiber fleeces can also be adjusted to customer specifications.

Wounds only heal quickly and effectively if the wounded tissue is sufficiently supplied with nutrients. At the same time, metabolic products have to be removed. In contrast to many products on the market that allow nutrient transport only after biodegradation has started, the open-meshed Renacer® membrane promotes this transport directly after implantation, while not allowing cell passage.

Membrane with an inorganic character
There is another advantage: The Renacer® membrane dissolves completely into almost pH neutral non-toxic ortho-silicic acid, the only water-soluble form of silica. It is physiologically present in the body and has been shown to stimulate connective skin tissue formation and bone formation. Products currently available do not exhibit such bioactive properties. Many biodegradable materials dissolve into organic acids, such as lactic acid or glycolic acid. This can cause local acidification in the tissue, which then triggers inflammatory reactions of the immune system. “Our tests have shown that the dissolution product, ortho-silicic acid, is also non-toxic and completely biocompatible with cells,” says Ziemann. “The membrane decomposes into a single molecule – ortho-silicic acid.”

Fibers as a depot for active substances
Furthermore, drugs can be encapsulated into the matrix of the silica gel fibers, to be released during material resorption. “For example, antibiotics could be delivered into a wound after applying a drug-loaded Renacer® membrane to prevent the formation of bacterial colonies,” elaborates Christ. At Fraunhofer ISC, the BMBF-funded GlioGel project is testing whether the Renacer® material platform can be used as a depot for active substances in the treatment of brain tumors.

Source:

Fraunhofer-Institut für Silicatforschung ISC

(c) Fraunhofer WKI
19.04.2023

Sustainable natural-fiber reinforcement for textile-reinforced concrete components

Textile-reinforced concrete components with a sustainable natural-fiber reinforcement possess sufficient bond and tensile load-bearing behavior for the utilization in construction. This has been verified by researchers at the Fraunhofer WKI in collaboration with Biberach University of Applied Sciences and the industrial partner FABRINO. In the future, textile-reinforced components with natural-fiber reinforcement could therefore replace conventionally reinforced concrete components and improve the environmental balance in the construction industry.

Textile-reinforced concrete components with a sustainable natural-fiber reinforcement possess sufficient bond and tensile load-bearing behavior for the utilization in construction. This has been verified by researchers at the Fraunhofer WKI in collaboration with Biberach University of Applied Sciences and the industrial partner FABRINO. In the future, textile-reinforced components with natural-fiber reinforcement could therefore replace conventionally reinforced concrete components and improve the environmental balance in the construction industry.

Non-metallic reinforcements for concrete elements are currently often made from various synthetically produced fibers - for example from glass or carbon fibers. An ecological alternative to synthetic fibers is provided by flax or other natural fibers. These are widely available and are more sustainable, due, amongst other things, to their renewable raw-material basis, the advantages regarding recycling, and the lower energy requirements during production. This is where the researchers from the Fraunhofer WKI and Biberach University of Applied Sciences, in collaboration with an industrial partner, became active. Their goal was to demonstrate that reinforcements made from textile fibers are just as suitable for utilization in construction as synthetic fibers.

"At the Fraunhofer WKI, we have produced leno fabrics from flax-fiber yarn using a weaving machine. In order to enhance sustainability, we tested a treatment of the flax yarns for improving the tensile strength, durability and adhesion which is ecologically advantageous compared to petro-based treatments," explained Jana Winkelmann, Project Manager at the Fraunhofer WKI. In the coating process, a commonly used petro-based epoxy resin was successfully replaced by a partially bio-based impregnation. A large proportion (56%) of the molecular structure of the utilized epoxy resin consists of hydrocarbons of plant origin and can therefore improve the CO2 balance.

Textile reinforcements have a number of fundamental advantages. They exhibit, for example, significantly reduced corrodibility at the same or higher tensile strength than steel, with the result that the necessary nominal dimension of the concrete covering can be reduced. This often allows smaller cross-sections to be required for the same load-bearing capacity. Up to now, however, the load-bearing behavior of textile reinforcements made from natural fibers in concrete components has not been systematically investigated.

At Biberach University of Applied Sciences, researchers tested the bond and tensile load-bearing behavior as well as the uniaxial flexural load-bearing behavior of concrete components with textile reinforcement made from flax fibers. The scientists came to the conclusion that the natural-fiber-based textile-reinforced components with a bio-based impregnation are fundamentally suitable. The suitability was demonstrated by both a significant increase in the breaking load compared to non-reinforced and under-reinforced concrete components and in finely distributed crack patterns. The curves of the stress-strain diagrams could be divided into three ranges typical for reinforced expansion elements (State I - non-cracked, State IIa - initial cracking, and State IIb - final crack pattern). The delineation of the ranges becomes more pronounced as the degree of reinforcement increases.

As a whole, regionally or Europe-wide available, renewable natural fibers and a partially bio-based coating contribute towards an improvement of the CO2 footprint of the construction industry. As a result, a further opportunity is being opened up for the energy- and raw-material-intensive construction industry in terms of meeting increasingly stringent environmental and sustainability requirements. "Textile-reinforced concretes enable lighter and more slender structures and therefore offer architectural leeway. We would like to continue our research into the numerous application possibilities of natural-fiber-reinforced concretes," said Christina Haxter, a staff member at the Fraunhofer WKI.

The project, which ran from 9th December 2020 to 31st December 2022, was funded by the German Federal Environmental Foundation (DBU).