Encouraged by her family, Lavender Tessmer explored various creative pursuits from a young age, particularly textiles, including knitting and crocheting. When she came to MIT, she figured that working with textiles would remain just a hobby; she never expected them to become integral to her career path.However, when she interviewed for a research assistant position in <a href="https://selfassemblylab.mit.edu/" target="_blank">Self Assembly Lab</a>, it just so happened that the lab had recently received funding from the Advanced Functional Fabrics of America, one of the <a href="https://obamawhitehouse.archives.gov/the-press-office/2016/06/20/fact-sheet-president-obama-announces-winner-new-smart-manufacturing" target="_blank">manufacturing institutes launched during the Obama administration</a>, for a textile-based project.Tessmer, now a fifth-year doctoral student in design and computation within the School of Architecture of Planning, took on the project, working with <a href="https://architecture.mit.edu/people/skylar-tibbits" target="_blank">Skylar Tibbits</a>, associate professor of design research, and <a href="https://cee.mit.edu/people_individual/caitlin-mueller/" target="_blank">Caitlin Muller</a>, associate professor in building technology. “At MIT, my interest in textiles really exploded and became the center of everything,” Tessmer says.While textiles may appear commonplace, the Covid-19 pandemic underscored the need for textile products in safeguarding our general health and safety, particularly through the filtration necessary for masks. Recognizing the importance of manufacturing capabilities for textiles, Tessmer’s research has focused on programming textiles with specific functional properties while also considering the feasibility of large-scale manufacturing of such products.<h2>A nonlinear path to MIT</h2>Tessmer studied music as an undergraduate student at Duquesne University, pursuing a passion that bloomed as a high schooler. One assignment opened her eyes to a different career path: She was told to compare a piece of music to some other artistic medium. Through this assignment, she discovered the world of architecture by underscoring the systematic nature of both disciplines, emphasizing the need for repetition and structure to unleash creativity. “I immediately realized that’s what I want to do,” she says.Tessmer switched gears and decided to devote the year after college to architecture, instead of auditioning for music ensembles. She says, “I always liked making things, and then, with architecture, I realized that you can make things as part of your profession.” She relied on the basic drafting skills that her father had taught her, and channeled these into building her architecture portfolio.Ultimately, she decided to pursue a master’s degree in architecture at Washington University in St. Louis. She graduated with her master’s at the end of the 2007 economic recession, a time when jobs in architecture were scarce. She eagerly accepted a part-time role teaching at WashU. Over the next five years, this role evolved into a full-time lecturer role, where she taught students while also independently establishing her own design practice and leading various installation design projects. Fittingly, all of the installations were inspired by textiles. “They were these high-performance carbon-fiber braided structures that we hand-made into large-scale braided nets with specific geometries,” Tessmer explains.<h2>“Squeezing everything” out of graduate school</h2>Teaching at WashU was a great experience, but the practice-oriented nature of the architecture department motivated Tessmer to seek complementary perspectives on design. “I wanted a totally new venue that was supportive of research and pushing the boundaries of design. I wanted to see what other approaches were out there,” she says. As her interests continued to grow in that direction, she learned that MIT has some renowned researchers in the field. She decided to apply for a master’s degree in architecture studies, and ultimately a doctorate in design and computation, within the School of Architecture and Planning.MIT’s program stood out to Tessmer because of the interdisciplinary approach of the architecture department. She says, “If you are an architect or designer, it is not strange to end up in a class full of people who are not architects, and that’s totally normal and even expected.” The integrated nature of her program is a shift from her previous academic experiences, where each discipline had been distinct and separate. She also values the lack of hierarchy between different disciplines within the architecture department here. “There is respect across disciplines for the contribution from each participant,” she says.As an older student, Tessmer has a slightly different approach to graduate school, compared to her peers. She says, “MIT is amazing because there is so much variety and so many things that you can get involved in. But my style is to be hyperfocused on my interests. For me, there have been huge benefits to focusing on this specific thing and squeezing everything I can out of it, even in the face of all of these other opportunities.”Tessmer has devoted herself to several projects throughout grad school, but all share a common thread: an emphasis on fiber development and textile programming. As a master’s student in the Self Assembly Lab, she utilized the inherent properties of materials and optimized their configurations for specific functions by integrating computation into the material itself. “At MIT, I learned a much broader definition of computation,” she says. “For example, in the Self Assembly Lab, we believe that material is a storage format of information and that you can program material to behave in certain ways.” &nbsp;The first project Tessmer worked on was designing a fiber that could respond to temperature fluctuations. Another project focused on embedding many different properties within a single fabric, potentially for astronauts. “The human body is so varied in the number of properties that you need to match,” she says. In conjunction with collaborators across multiple MIT departments, she designed a spacesuit sleeve with embedded padding, stretchable areas, a compression gradient, and various sensors. Her third project has focused on embedding shapechange behavior into fabric structures to enhance human comfort or fit, as an alternative to manual tailoring. Finally, in a return to her architectural roots, she is also working on designing a reinforced concrete beam using textiles, a more sustainable solution to building with concrete, which has a significant carbon footprint.Another crucial aspect of Tessmer’s research is her focus on the feasibility of large-scale manufacturing for a product. She regularly relies on industrial-scale machinery and consults with manufacturing partners. She says, “The way research is being conducted in the lab is a close parallel to how it would be made in real life. The potential for a direct bridge between one and the other is a high priority for me and a constraint that I have tried to layer on to all of my projects.”<h2>Dabbling in entrepreneurship</h2>Tessmer says with a laugh, “My entire hobby [textiles] has now been absorbed into my research. So I am in the market for a new hobby.” For now, that hobby has taken the form of entrepreneurship. She has been exploring the commercialization potential of her technologies, having filed multiple patents and completed the <a href="https://engine.xyz/blueprint" target="_blank">Blueprint</a> program with The Engine Accelerator. She hopes that one day her method for embedding properties in textiles, while also reducing manufacturing process steps, will be used for commercial fabrics.As an example, she points to shoe manufacturing. “Your shoes are normally an assembly of lots of different materials and lots of different layers. Instead, my proposal to The Engine focused on embedding all of these properties in an automated way, eliminating the need for an extensive assembly process.” Tessmer envisions entrepreneurship as one of her potential future paths.For the time being, however, she plans to remain in academia. “From the outside, being a professor seems like an unattainable position. However, I keep being surprised at my ability to get to the next level of the academic hierarchy.” She aims to integrate all her past experiences into a future research career, designing textiles within an architectural context, while also weaving in the constraints of manufacturing scalability.

PhD student Lavender Tessmer has devoted herself to several projects throughout grad school, but all share a common thread: an emphasis on fiber development and textile programming. “At MIT, my interest in textiles really exploded and became the center of everything,” she says. Photo: Gretchen Ertl

PhD student Lavender Tessmer applies computation to create textiles that behave in novel ways.

Programming functional fabrics

Robotic exoskeletons designed to help humans with walking or physically demanding work have been the stuff of sci-fi lore for decades. Remember <a href="https://youtu.be/jtVygtT8VIc" target="_blank">Ellen Ripley in that Power Loader in Alien</a>? Or the crazy mobile platform <a href="https://youtu.be/Z2OLmFw9wR8?si=hIsWKAiRYAWGWbpP&t=85" target="_blank">George McFly wore in 2015 in Back to the Future, Part II</a> because he threw his back out?Researchers are working on real-life robotic assistance that could protect workers from painful injuries and help stroke patients regain their mobility. So far, they have required extensive calibration and context-specific tuning, which keeps them largely limited to research labs.Mechanical engineers at Georgia Tech may be on the verge of changing that, allowing exoskeleton technology to be deployed in homes, workplaces, and more.A team of researchers in <a href="https://me.gatech.edu/faculty/young" target="_blank">Aaron Young’s</a> lab have developed a universal approach to controlling robotic exoskeletons that requires no training, no calibration, and no adjustments to complicated algorithms. Instead, users can don the “exo” and go.Their system uses a kind of artificial intelligence called deep learning to autonomously adjust how the exoskeleton provides assistance, and they’ve shown it works seamlessly to support walking, standing, and climbing stairs or ramps. <a href="https://doi.org/10.1126/scirobotics.adi8852" target="_blank">They described their “unified control framework” March 20 in Science Robotics.</a>“The goal was not just to provide control across different activities, but to create a single unified system. You don't have to press buttons to switch between modes or have some classifier algorithm that tries to predict that you're climbing stairs or walking,” said Young, associate professor in the <a href="https://me.gatech.edu/" target="_blank">George W. Woodruff School of Mechanical Engineering</a>.<h3>Machine Learning as Translator</h3><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1711697656575-_MG_8945.webp" style="width: 100%px;" class="fr-fic fr-dib">A closeup view of experimental exoskeleton used in experiments that resulted in a universal controller for robotic assistance devices.Most previous work in this area has focused on one activity at a time, like walking on level ground or up a set of stairs. The algorithms involved typically try to classify the environment to provide the right assistance to users.The Georgia Tech team threw that out the window. Instead of focusing on the environment, they focused on the human — what’s happening with muscles and joints — which meant the specific activity didn’t matter.“We stopped trying to bucket human movement into what we call discretized modes — like level ground walking or climbing stairs&nbsp;— because real movement is a lot messier,” said Dean Molinaro, lead author on the study and a recently graduated Ph.D. student in Young’s lab. “Instead, we based our controller on the user’s underlying physiology. What the body is doing at any point in time will tell us everything we need to know about the environment. Then we used machine learning essentially as the translator between what the sensors are measuring on the exoskeleton and what torques the muscles are generating.”With the controller delivering assistance through a hip exoskeleton developed by the team, they found they could reduce users’ metabolic and biomechanical effort: they expended less energy, and their joints didn’t have to work as hard compared to not wearing the device at all.In other words, wearing the exoskeleton was a benefit to users, even with the extra weight added by the device itself.<blockquote>What’s so cool about this [controller] is that it adjusts to each person’s internal dynamics without any tuning or heuristic adjustments, which is a huge difference from a lot of work in the field. There’s no subject-specific tuning or changing parameters to make it work.AARON YOUNG Associate Professor, Mechanical Engineering</blockquote><a href="https://doi.org/10.1126/scirobotics.adi8852" target="_blank">The control system in this study</a> is designed for partial-assist devices. These exoskeletons support movement rather than completely replacing the effort.The team, which also included Molinaro and <a href="https://www.meche.engineering.cmu.edu/directory/bios/kang-inseung.html" target="_blank">Inseung Kang</a>, another former Ph.D. student now at Carnegie Mellon University, used an existing algorithm and trained it on mountains of force and motion-capture data they collected in Young’s lab. Subjects of different genders and body types wore the powered hip exoskeleton and walked at varying speeds on force plates, climbed height-adjustable stairs, walked up and down ramps, and transitioned between those movements.And like the motion-capture studios used to make movies, every movement was recorded and cataloged to understand what joints were doing for each activity.The <a href="https://doi.org/10.1126/scirobotics.adi8852" target="_blank">Science Robotics study</a> is “application agnostic,” as Young put it. Yet their controller offers the first bridge to real-world viability for robotic exoskeleton devices.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1711697699313-_MG_8771.webp" style="width: 100%px;" class="fr-fic fr-dib">Researchers Aaron Young, left, and Dean Molinaro.Imagine how robotic assistance could benefit soldiers, airline baggage handlers, or any workers doing physically demanding jobs where musculoskeletal injury risk is high.Assistive robotics also could help stroke patients regain mobility. Related experiments in Young’s lab are working to understand how their hip exoskeleton and unified controller could be extended to help people recovering from stroke navigate their communities.<iframe width="640" height="360" src="https://www.youtube.com/embed/VEvV1jnqacs?&amp;wmode=opaque&amp;rel=0&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" frameborder="0" allowfullscreen="" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe><h3 id="isPasted">Helping Amputees Do More</h3>Other projects in Young’s <a href="https://www.epic.gatech.edu/" target="_blank">Exoskeleton and Prosthetic Intelligent Controls (EPIC) Lab</a> are marrying the power of robotics and AI to help adults with above-the-knee amputations navigate more effectively and children recover from neurological injuries.For adults, the lab is imagining new powered prostheses to help them navigate the world. An active study is exploring how AI can learn a patient’s gait and adapt over time to improve walking.Stacey Rice has been working with the team for a year, testing iterations of a leg prosthesis and the accompanying AI controller. She lost her leg to bone cancer 44 years ago, so she’s already seen technology improve the devices available to amputees.&nbsp;The Atlanta native is a multisport athlete and 1988 volleyball Paralympian. She said she can feel a real difference in the amount of effort she expends using the robotic assistance. <blockquote>I realized while I was on the treadmill that I wasn’t using as much energy as if I was using my own prosthesis. For me to have that energy bank is huge. There’s so much energy the body uses when you’re an amputee and you’re walking. To reserve that energy for your day-to-day activities will allow amputees to be more active during the day and do more.STACEY RICE Amputee and Research Study Participant</blockquote><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1711697760246-_MG_8899.webp" style="width: 100%px;" class="fr-fic fr-dib">Dean Molinaro walks up a height-adjustable ramp, left, and similarly adjustable stairs, right, while wearing an experimental exoskeleton. The team used these and other unique tools Young's lab, such as force plates and motion-capture cameras, to collect data in their effort to develop a unified control framework for robotic assistance devices.<h3 id="isPasted">Gamifying Pediatric Rehab<a title="Permalink to this item" href="https://coe.gatech.edu/news/2024/03/universal-controller-could-push-robotic-prostheses-exoskeletons-real-world-use#gamifying-pediatric-rehab" target="_blank"></a></h3>In other experiments, Young’s lab is working with Children’s Healthcare of Atlanta and Shriners Hospital to incorporate robotics into a new approach to pediatric rehabilitation that helps patients improve their gait.&nbsp;Kids with cerebral palsy, traumatic brain injuries, and other conditions often undergo physical therapy to help correct walking abnormalities. Incorporating robotics into the process is an area Young is excited about because developing brains are especially good at relearning skills and can recover function over time.“The robotic therapy does what a physical therapist might do manually, but in an automated way. It encourages them to adopt better gait biomechanics,” Young said.In each appointment, the researchers combine a robotic exoskeleton with biofeedback systems through a game-like interface.“When the patients come in, it’s like a video game that they're playing, which both engages them and gives them feedback about their performance,” Young said. “We want them to internalize the learning. The exoskeleton will help them physically achieve their goals, but we need them to retain that and engage in the rehab process.”<h3>Regaining Balance<a title="Permalink to this item" href="https://coe.gatech.edu/news/2024/03/universal-controller-could-push-robotic-prostheses-exoskeletons-real-world-use#regaining-balance" target="_blank"></a></h3>Elsewhere in the lab, Young and his team use a unique virtual-reality treadmill system to study gait and balance, particularly for older adults or people with mobility issues from strokes or amputations.The team uses the platform to introduce significant disruptions while participants are walking, challenging them to keep or regain their balance. The resulting data —&nbsp;largely from young, athletic individuals —&nbsp;is inspiring how wearable robots should operate to help people with balance impairments stay upright.In other words, it’s a busy place. And all in service of making a future of wearable robotics a reality.“For a lot of us, mobility is something we’re able to take for granted. One of the hopes is that this work can translate to people with mobility impairments and improve their quality of life,” Molinaro said. “And also, there are times when mobility is a limitation. So we’re interested in how we push the edge of mobility, both in restoring it for those with impairments but also augmenting it for those of able body to make them even more capable.”

Researcher Aaron Young makes adjustments to an experimental exoskeleton worn by then-Ph.D. student Dean Molinaro. The team used the exoskeleton to develop a unified control framework for robotic assistance devices that would allow users to put on an "exo" and go — no extensive training, tuning, or calibration required. (Photo: Candler Hobbs)

Aaron Young’s team has developed a wear-and-go approach that requires no calibration or training.

Universal Controller Could Push Robotic Prostheses, Exoskeletons Into Real-World Use

Small wearable or implantable electronics could help monitor our health, diagnose diseases, and provide opportunities for improved, autonomous treatments. But to do this without aggravating or damaging the cells around them, these electronics will need to not only bend and stretch with our tissues as they move, but also be soft enough that they will not scratch and damage tissues.Researchers at Stanford have been working on skin-like, stretchable electronic devices for over a decade. In a paper published March 13 in Nature, they present a new design and fabrication process for skin-like integrated circuits that are five times smaller and operate at one thousand times higher speeds than earlier versions. The researchers demonstrated that their soft integrated circuits are now able to drive a micro-LED screen and detect a braille array that is more sensitive than human fingertips.“We’ve made a significant leap forward. For the first time, stretchable integrated circuits are now small enough and fast enough for many applications,” said <a href="https://mandrillapp.com/track/click/30855492/profiles.stanford.edu?p=eyJzIjoiOVAtVVZYVEltMTAyQXVpZ2ppSmFNd3RkQjNvIiwidiI6MSwicCI6IntcInVcIjozMDg1NTQ5MixcInZcIjoxLFwidXJsXCI6XCJodHRwczpcXFwvXFxcL3Byb2ZpbGVzLnN0YW5mb3JkLmVkdVxcXC96aGVuYW4tYmFvXCIsXCJpZFwiOlwiMGM2YWMxYWU5MTg4NGZjYWFjMzI1ZDc2M2MyZDhhODdcIixcInVybF9pZHNcIjpbXCJkMGY0ZGMxYjBmMDE3OTkzNjhmOGE4NzJlMmViNzQ3ZTFjZmNmMjBkXCJdfSJ9" data-extlink="" target="_blank">Zhenan Bao</a>, a K. K. Lee Professor in Chemical Engineering at Stanford and senior author on the paper. “We hope that this can make wearable sensors and implantable neural and gut probes more sensitive, operate more sensors, and potentially consume less power.”<h2>Flexible, stretchable, and functional</h2>The core of the circuits are stretchable transistors made from semiconducting carbon nanotubes and soft elastic electronic materials developed in Bao’s lab. Unlike silicon, which is hard and brittle, the carbon nanotubes sandwiched between elastic materials have a fishnet-like structure that allows them to continue to function while they stretch and deform. The transistors and circuits are patterned onto a stretchable substrate, along with stretchable semiconductor, conductor, and dielectric material.“This is many years of material and engineering development,” Bao said. “We not only needed to develop new materials, but we also needed to develop the circuit design and the fabrication process to make the circuits. There are many layers stacked together and if one layer doesn’t work, we have to restart everything from scratch.”In one demonstration of their new stretchable electronics design, the researchers were able to fit more than 2,500 sensors and transistors into a square centimeter, creating an active-matrix tactile array over ten times more sensitive than human fingertips. The researchers showed that the sensor array can detect the locations and orientation of tiny shapes or recognize whole words in Braille.“With Braille, you usually sense one letter at a time,” said <a href="https://mandrillapp.com/track/click/30855492/baogroup.stanford.edu?p=eyJzIjoiQWFWMU9jM2VqYXZMR2g5TFVfMnRPcTE4cGxnIiwidiI6MSwicCI6IntcInVcIjozMDg1NTQ5MixcInZcIjoxLFwidXJsXCI6XCJodHRwczpcXFwvXFxcL2Jhb2dyb3VwLnN0YW5mb3JkLmVkdVxcXC9wZW9wbGVcXFwvZG9uZ2xhaS16aG9uZ1wiLFwiaWRcIjpcIjBjNmFjMWFlOTE4ODRmY2FhYzMyNWQ3NjNjMmQ4YTg3XCIsXCJ1cmxfaWRzXCI6W1wiNTgyODY0ZTdiMWU3NWU4ZGRiOWM5OWIyOTI5YWU1YTFiODU3MDZiYVwiXX0ifQ" data-extlink="" target="_blank">Donglai Zhong</a>, a postdoctoral researcher in Bao’s lab and co-first author on the paper. “With such a high resolution, you could sense a whole word, or potentially a whole sentence, with just one touch.”The researchers also used their stretchable circuits to drive a micro-LED display with a refresh rate of 60 Hz, which is the typical refresh rate of a computer or TV screen. Previous versions of the stretchable circuits weren’t fast enough at small sizes to generate enough current to accomplish this.“We’re really excited about these performance improvements because they enable us to do a lot of new things,” said <a href="https://mandrillapp.com/track/click/30855492/baogroup.stanford.edu?p=eyJzIjoia1V0NTdYUFNUVGxncTZEZFg0RWh1MGRnRDg0IiwidiI6MSwicCI6IntcInVcIjozMDg1NTQ5MixcInZcIjoxLFwidXJsXCI6XCJodHRwczpcXFwvXFxcL2Jhb2dyb3VwLnN0YW5mb3JkLmVkdVxcXC9wZW9wbGVcXFwvY2FuLXd1XCIsXCJpZFwiOlwiMGM2YWMxYWU5MTg4NGZjYWFjMzI1ZDc2M2MyZDhhODdcIixcInVybF9pZHNcIjpbXCI4MTliZDk3YzY5NzMxMjg0ZjcwMDgwNTY4MDdhZjFjOGNlYmE0ZTExXCJdfSJ9" data-extlink="" target="_blank">Can Wu</a>, a postdoctoral researcher in Bao’s lab and co-first author on the paper. “Preliminary results demonstrate that our transistor can be used to drive commercial displays commonly used in computer monitors, for example. And for biomedical applications, a high-density, soft, and conformable sensing array could allow us to sense human body signals, such as from our brains and muscles, at a large scale and fine resolution. This could lead to next-generation brain-machine interfaces that are both high-performance and biocompatible.”<h2>Soft circuits for the future</h2>The researchers intentionally developed materials and processes that could work with existing fabrication tools, so that the circuits could make the jump to commercial manufacturing more easily. Their process relies on fabrication techniques similar to what is currently used for making display screens, although the materials involved are entirely different. Manufacturers wouldn’t be able to make these circuits without some additional fine-tuning, but the tools are already in place, Bao said.Of course, there are more hurdles before these stretchable and soft integrated circuits can be ready for commercialization. Body and tissue movement can still cause some variation in the electrical characteristics of the circuits – Bao and her colleagues are working on new designs that could reduce these effects – and the devices will need some sort of soft moisture protection before they can be put to use.“There are still challenges for the future of this technology, but these recent developments open up some very exciting biomedical applications for wearable and implantable electronics,” Bao said. “And it also has applications in soft robotics, giving robots a sensing functionality that approaches that of humans and makes them safer for people to work with.”Bao is a member of&nbsp;<a href="https://biox.stanford.edu/" data-extlink="" target="_blank">Stanford Bio-X</a>, the&nbsp;<a href="https://med.stanford.edu/cvi.html" data-extlink="" target="_blank">Stanford Cardiovascular Institute</a>, the&nbsp;<a href="https://humanperformance.stanford.edu/" data-extlink="" target="_blank">Wu Tsai Human Performance Alliance</a>, the&nbsp;<a href="https://neuroscience.stanford.edu/" data-extlink="" target="_blank">Wu Tsai Neurosciences Institute</a>, and the&nbsp;<a href="https://med.stanford.edu/mchri.html" data-extlink="" target="_blank">Maternal &amp; Child Health Research Institute</a>; an affiliate of the&nbsp;<a href="https://energy.stanford.edu/" data-extlink="" target="_blank">Precourt Institute for Energy</a>&nbsp;and the&nbsp;<a href="https://woods.stanford.edu/" data-extlink="" target="_blank">Stanford Woods Institute for the Environment</a>; and a faculty fellow of&nbsp;<a href="https://chemh.stanford.edu/" data-extlink="" target="_blank">Sarafan ChEM-H</a>. Bao is an investigator of CZ-Biohub-San Francisco and an innovation investigator of Arc Institute.Other Stanford co-authors of this research include research scientist Jeffrey B.-H. Tok; postdoctoral researchers Yuanwen Jiang (Co-first-author), Min-gu Kim, Chien-Chung Shih, Jian-Cheng La, Chuanzhen Zhao, Shiyuan Wei, Xiaozhou Ji, Yi-Xuan Wang, Chengyi Xu, Naoji Matsuhisa, Yusheng Lei, Deya Liu, Song Zhang, and Yuto Ochiai; and doctoral students Yujia Yuan, Yuya Nishio, Weichen Wang, Theodore Z. Gao, Yu Zheng, Zhiao Yu, Huaxin Gong, and Shuhan Liu.

Intrinsically stretchable transistors and integrated circuits under large deformation after being released from the supporting substrate. | Image courtesy of Donglai Zhong, Jiancheng Lai, and Yuya Nishio of the Bao Group

Stanford researchers have developed soft integrated circuits that are powerful enough to drive a micro-LED screen and small enough to read thousands of sensors in a single square centimeter.

Smaller, more powerful stretchable electronics for wearables and implantables

This article was discussed in our <a href="https://www.wevolver.com/profile/the.next.byte" rel="noopener noreferrer" target="_blank">Next Byte podcast</a>.&nbsp;<iframe height="200px" width="100%" frameborder="no" scrolling="no" seamless="" src="https://player.simplecast.com/7a6ed573-f46a-40bb-b396-d38d1207aa2e?dark=false" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe> The full article will continue below.<hr>Until recently, bespoke tailoring — clothing made to a customer’s individual specifications — was the only way to have garments that provided the perfect fit for your physique. For most people, the cost of custom tailoring is prohibitive. But the invention of active fibers and innovative knitting processes is changing the textile industry.“We all wear clothes and shoes,” says Sasha MicKinlay MArch ’23, a recent graduate of the MIT Department of Architecture. “It’s a human need. But there’s also the human need to express oneself. I like the idea of customizing clothes in a sustainable way. This dress promises to be more sustainable than traditional fashion to both the consumer and the producer.”McKinlay is a textile designer and researcher at the Self-Assembly Lab who designed the <a href="https://selfassemblylab.mit.edu/4d-knit-dress" target="_blank">4D Knit Dress</a> with Ministry of Supply, a fashion company specializing in high-tech apparel. The dress combines several technologies to create personalized fit and style. Heat-activated yarns, computerized knitting, and robotic activation around each garment generates the sculpted fit. A team at Ministry of Supply led the decisions on the stable yarns, color, original size, and overall design.“Everyone’s body is different,” says Skylar Tibbits, associate professor in the Department of Architecture and founder of the Self-Assembly Lab. “Even if you wear the same size as another person, you're not actually the same.”<iframe width="640" height="360" src="https://player.vimeo.com/video/893959788" frameborder="0" allowfullscreen="" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true">&nbsp;&nbsp;&nbsp;&nbsp;</iframe>4D Knit Dress: Transforming Style. Video: Self-Assembly Lab<h2 id="isPasted">Active textiles</h2>Students in the Self-Assembly Lab have been working with dynamic textiles for several years. The yarns they create can change shape, change property, change insulation, or become breathable. Previous applications to tailor garments include <a href="https://selfassemblylab.mit.edu/active-textile-tailoring" target="_blank">making sweaters</a> and <a href="https://news.mit.edu/2022/form-fitting-face-mask-lavender-tessmer-0718" target="_blank">face masks</a>. Tibbits says the 4D Knit Dress is a culmination of everything the students have learned from working with active textiles.McKinlay helped produce the active yarns, created the concept design, developed the knitting technique, and programmed the lab’s industrial knitting machine. Once the garment design is programmed into the machine, it can quickly produce multiple dresses. Where the active yarns are placed in the design allows for the dress to take on a variety of styles such as pintucks, pleats, an empire waist, or a cinched waist.“The styling is important,” McKinlay says. “Most people focus on the size, but I think styling is what sets clothes apart. We’re all evolving as people, and I think our style evolves as well. After fit, people focus on personal expression.”<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzEwMTM1NjY2MDgwLU1pbmlzdHJ5X0ZJTkFMX2RyZXNzZXMuanBnIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 100%px;" class="fr-fic fr-dib">Designers explored this series of possible styles for the robotic heat activation of the 4D Knit Dress. Image courtesy of the Self-Assembly Lab.Danny Griffin MArch ’22, a current graduate student in architectural design, doesn’t have a background in garment making or the fashion industry. Tibbits asked Griffin to join the team due to his experience with robotics projects in construction. Griffin translated the heat activation process into a programmable robotic procedure that would precisely control its application.“When we apply heat, the fibers shorten, causing the textile to bunch up in a specific zone, effectively tightening the shape as if we’re tailoring the garment,” says Griffin. “There was a lot of trial and error to figure out how to orient the robot and the heat gun. The heat needs to be applied in precise locations to activate the fibers on each garment. Another challenge was setting the temperature and the timing for the heat to be applied.”It took a while to determine how the robot could&nbsp;reach all areas of the dress.“We couldn’t use a commercial heat gun — which is like a handheld hair dryer — because they’re too large,” says Griffin. “We needed a more compact design. Once we figured it out, it was a lot of fun to write the script for the robot to follow.”A dress can begin with one design — pintucks across the chest, for example — and be worn for months before having heat re-applied to alter its look. Subsequent applications of heat can tailor the dress further.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzEwMTM1NjgyOTQyLVJvYm90aWNfYXJtX2F0X3dvcmsuanBlZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 100%px;" class="fr-fic fr-dib">Robotic heat activation can be seen during a demonstration at Ministry of Supply in Boston. Photo: Olivia Mintz<h2>Beyond fit and fashion</h2>Efficiently producing garments is a “big challenge” in the fashion industry, according to Gihan Amarasiriwardena ’11, the co-founder and president of Ministry of Supply.“A lot of times you'll be guessing what a season's style is,” he says. “Sometimes the style doesn't do well, or some sizes don’t sell out. They may get discounted very heavily or eventually they end up going to a landfill.”“Fast fashion” is a term that describes clothes that are inexpensive, trendy, and easily disposed of by the consumer. They are designed and produced quickly to keep pace with current trends. The 4D Knit Dress, says Tibbits, is the opposite of fast fashion. Unlike the traditional “cut-and-sew” process in the fashion industry, the 4D Knit Dress is made entirely in one piece, which virtually eliminates waste.“From a global standpoint, you don’t have tons of excess inventory because the dress is customized to your size,” says Tibbits.McKinlay says she hopes use of this new technology will reduce the amount of waste in inventory that retailers usually have at the end of each season.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzEwMTM1NzEwMDIxLU1pbmlzdHJ5X0ZJTkFMX0RyYWZ0MDUgY29weS5qcGVnIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 100%px;" class="fr-fic fr-dib">A complete 4D Knit Dress comes out of a Stoll industrial knitting machine after being produced in one piece, without any cutting or sewing. Photo courtesy of the Self-Assembly Lab.“The dress could be tailored in order to adapt to these changes in styles and tastes,” she says. “It may also be able to absorb some of the size variations that retailers need to stock. Instead of extra-small, small, medium, large, and extra-large sizes, retailers may be able to have one dress for the smaller sizes and one for the larger sizes. Of course, these are the same sustainability points that would benefit the consumer.”The Self-Assembly Lab has collaborated with Ministry of Supply on projects with active textiles for several years. Late last year, the team debuted the <a href="https://selfassemblylab.mit.edu/4d-knit-dress" target="_blank">4D Knit Dress</a> at the company’s flagship store in Boston, complete with a robotic arm working its way around a dress as customers watched. For Amarasiriwardena, it was an opportunity to gauge interest and receive feedback from customers interested in trying the dress on.“If the demand is there, this is something we can create quickly” unlike the usual design and manufacturing process, which can take years, says Amarasiriwardena.Griffin and McKinlay were on hand for the demonstration and pleased with the results. For Griffin, with the “technical barriers” overcome, he sees many different avenues for the project.“This experience leaves me wanting to try more,” he says.McKinlay too would love to work on more styles.“I&nbsp;hope this research project helps people rethink or reevaluate their relationship with clothes,” says McKinlay. “Right now when people purchase a piece of clothing it has only one ‘look.’ But, how exciting would it be to purchase one garment and reinvent it to change and evolve as you change or as the seasons or styles change? I'm hoping that's the takeaway that people will have.”

Caption:In late 2023 the MIT Self Assembly Lab and the high-tech fashion company Ministry of Supply debuted their 4D Knit Dress at the latter's store Boston, complete with a robotic arm working its way around a dress as customers watched. Credits:Image courtesy of MIT Self Assembly Lab

Developed by the Self-Assembly Lab, the 4D Knit Dress uses several technologies to create a custom design and a custom fit, while addressing sustainability concerns.

Is this the future of fashion?

Wearable electronic devices designed to be worn while in use are becoming more popular and powerful as they can monitor various aspects of human health, activity, and environment. However, these devices also face challenges such as limited battery life, data privacy, and network bandwidth. To overcome these challenges, edge computing and AI/ML are emerging as key technologies that can enable wearable devices to process data locally, reduce latency, and enhance user experience.&nbsp;As wearable technologies evolve to meet market needs, new devices are upgrading features such as basic BLE connectivity by adding the ability to run AI algorithms on neural processors on-device rather than in the cloud. This reduces the amount of data that needs to be transmitted over the network, saving energy and bandwidth. With the AI/ML models running in silicon, wearable devices can, therefore, learn from data and perform tasks such as recognition, classification, prediction, and optimization without incurring additional latency, data costs, and power consumption. However, these improvements require greater processing power and capabilities from embedded microcontrollers (MCUs) and application processors. At the same time, consumers expect longer battery life from their wearables. Thus, new chips must balance connectivity and higher processing power with low power consumption while maintaining a small enough package size.&nbsp;This case study explores the challenges for the next generations of wearable MCUs with a specific look at <a href="https://alifsemi.com/" target="_blank" rel="noopener noreferrer">Alif Semiconductor's®</a> Balletto™ family of BLE-enabled MCUs for wearable applications.<h2 dir="ltr">The current landscape</h2>The wearables market, which includes common accessories such as smart bands, smart rings, smartwatches, and medical devices, such as glucose monitoring devices is projected to grow to USD 118.16 billion by 2028 at a 13.8% CAGR. Demand for multimedia devices, smartphones, fitness trackers, and health wearables drives growth. Increasing health awareness fuels interest in fitness tracking devices for activities like cycling and running, contributing to market expansion.[2,3]Wearables have evolved significantly in recent years, presenting enhanced capabilities in various domains, such as AI processing and wirelessly transmitting data. New market demands have driven the expansion of wearable features. For example, the COVID-19 pandemic made blood oxygen sensing a must-have feature for many smartwatches. As a result, Apple and Samsung included blood oxygen monitoring in their smartwatches in 2020.Wearables incorporate edge AI-based solutions to process huge amounts of data in real-time. AI-enabled microcontrollers are a must to carry out these large AI/ML workloads efficiently and quickly. The integration of artificial intelligence enables new features, such as:<ul><li dir="ltr">Tracking and analyzing changes in users’ health data.</li><li dir="ltr">Sending users alerts for noise levels or air quality.</li><li dir="ltr">Personalize your device based on your tracked activity.&nbsp;</li></ul>Equally important as collecting and processing user data is the ability to wirelessly share data between devices. As such, Bluetooth connectivity has risen as a top requirement for wearables including functionalities, such as:&nbsp;<ul><li dir="ltr">Sending an alert to emergency services if a fall is detected.</li><li dir="ltr">Sharing important health updates with an approved health care professional.</li><li dir="ltr">Sharing workout metrics with a friend to stay motivated.</li></ul><h2 dir="ltr">Bluetooth LE changes the status quo in wearables</h2>Among the many low-power wireless technologies on the market, Bluetooth Low Energy (BLE) technology is uniquely suited for wearable devices that require long battery life measured in days or even weeks before needing to be recharged. BLE allows wearables to easily connect and communicate with other devices, such as smartphones, tablets, exercise equipment, or even other wearables.&nbsp;This enhances the device's functionality by enabling it to share exercise data, receive timely notifications, and more. Increasingly, wearable devices are adding audio support for which BLE is uniquely positioned. With the addition of support for the Low Complexity Communication Codec (LC3), BLE is now capable of use cases such as broadcast audio and shared or group listening experiences with LE Audio’s Auracast feature. For example, a wearable device can use the on-device neural processor such as Arm’s Ethos-U55 to run a convolutional neural network (CNN) model for gesture recognition or activity classification based on the motion data captured by inertial measurement units (IMUs). The device can then use BLE to communicate with other devices or a smartphone app to provide feedback or instructions to the user.&nbsp;In the Smart Home, wearables can be integrated into a smart home system, with AI algorithms learning the user's habits and preferences to automate various home appliances. BLE 5.4's enhanced performance and range can facilitate efficient communication with many IoT devices in the home. For example, a wearable could learn that a user likes to listen to calming music when they get home from work and automatically instruct the smart speaker to play the user's favorite playlist when they walk through the door.&nbsp;Additionally, features allow wearables to be located precisely, while location-based services (LBS) such as personalized fitness coaching (created by learning from a user’s previous workout data) can be enabled. It can suggest workout routines tailored to the user's fitness goals and current health status. The wearable device can recognize the user’s activity and posture using an ML model that runs on the Ethos-U55 core and sends the data to a cloud service via Enhanced Attribute Protocol (EAP). This could enable personalized, reliable, and secure fitness tracking for the user.&nbsp;<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzEzMTY0MTY0MDQ1LVdob29wLUJvZHlUcmFpbmluZy1Ub3AuanBnIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 100%px;" class="fr-fic fr-dib">Next-gen wearables will enable highly-personal fitness tracking. Credit: WHOOP.&nbsp;AI/ML algorithms can be trained to detect patterns in biometric data gathered by wearables, such as heart rate, blood pressure, and oxygen saturation levels. BLE's enhanced broadcast communication mechanism (EAD, PAwR) can allow these devices to send real-time health risk alerts to other devices, such as a smartphone, even in congested or high-interference environments. For example, a wearable could alert a user or a healthcare provider if it detects signs of an impending health crisis like a heart attack or stroke.&nbsp;When you combine AI-enabled MCUs with BLE, wearables become more personalized, efficient, secure, and useful in our everyday lives. Alif Semiconductor <a href="https://alifsemi.com/press-release/first-ble-matter-wireless-microcontroller-with-neural-co-processor-for-ai-ml/" target="_blank">has just announced</a> their Balletto family of BLE and Matter microcontrollers&nbsp;with neural processing for AI/ML workloads, which seeks to exceed the standard for low-power BLE operations.<h2 dir="ltr">Hardware accelerated machine learning</h2>To meet the market-need for state-of-the-art wearables, Alif Semiconductor offers AI/ML-enabled microcontrollers with dedicated NPU accelerators that allow heavy AI/ML workloads to run without compromising battery life. <a href="https://alifsemi.com/products/balletto/" target="_blank" id="isPasted">The Alif Balletto family</a> of microcontrollers introduces the world's most power-efficient microcontroller with on-device secure AI/ML processing, top-notch security, and ample peripherals for applications requiring integrated Bluetooth Low Energy and 802.15.4-based connectivity.&nbsp;The Balletto family boasts the powerful Arm® Cortex®-M55 core, equipped with double-precision FPU and Helium Vector Extensions, operating at a remarkable speed of up to 160MHz. Arm Ethos-U55 is a dedicated NPU accelerator that offloads AI/ML operations from the Cortex-M55 processor, allowing the M55 cores to operate in very low-power modes. This is especially important for wearables like hearing aids, which need to have a long battery life. Equally as important for wearables is having a small form-factor design, which Balletto can provide in a sub 16mm ² package. &nbsp;&nbsp;Balletto’s Ethos™-U55 Neural Processing Unit (NPU) can improve the performance and efficiency of speech recognition machine learning models by up to two orders of magnitude, excluding the 5-10x improvement already provided by the Cortex-M55 core over previous generation Cortex-M CPUs. This is ideal for wearables that rely on voice commands, improving processing speed and lowering latency.&nbsp;<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzEyODQyNDU1ODU5LWFsaWYgbWFpbiAyLnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 100%px;" class="fr-fic fr-dib">Balletto and Ensemble families. Image credit: Alif Semiconductor.<h3 dir="ltr" id="isPasted">Battery-friendly microcontrollers powered by Alif’s aiPM™ technology&nbsp;</h3>The Balletto family also tackles a common problem seen by previously existing AI/ML-powered microcontrollers: short battery life. Connected wearables or mission-critical devices like hearing aids depend on long battery life for users. Their ability to function is hindered when there is a need for heavy local processing and AI/ML. Balletto MCUs are the most power-efficient in their class, thanks to Alif's innovative aiPM technology. This technology manages all aspects of the device, including individual processing cores for real-time control, neural processing, DSP and audio, deep security, and radio protocols capable of BLE 5.4 with LE Audio, Thread, and Matter. Balletto devices also include a wide range of interfaces and large memories, all monolithically integrated inside extremely small packages. This makes them ideal for demanding battery-powered applications such as wearables and hearables.Alif Semiconductor’s aiPM technology manages the power usage of the device through 8 power domains. It activates only the necessary chip sections and deactivates them when not in use, resulting in a highly efficient always-on region when there is a high requirement for local processing and AI/ML. The integrated dual-PA and on-chip antenna gives customers control of the reliability-range equation by providing tuning options of 4 dBm or up to 10 dBm Bluetooth transmit power. &nbsp;Balletto’s Bluetooth radio has a receive current of 1.5mA and a transmit current of 2.0mA, making it power conscious.Additionally, off-die peripherals produce higher energy consumption for wearables, while Balletto’s on-die solution fosters maximum efficiency. Utilization of the internal bus fabric effectively lowers access time, dynamic power, and standby power, ultimately providing more granular and precise power control at a lower cost.&nbsp;<h3 dir="ltr">Balletto family multi-layered security</h3>In addition to handling processing requirements, microcontrollers for wearables must ensure data security. Alif Balletto microcontrollers provide exceptional security features with multiple layers of protection, including:<ul><li dir="ltr">Root of Trust</li><li dir="ltr">Unique device ID for each individual chip</li><li dir="ltr">Dedicated security processor</li><li dir="ltr">Dedicated protected memory</li><li dir="ltr">Configurable firewalls that regulate access of each CPU to sections of memories and individual peripherals and extend the capabilities of the standard Arm Trust Zone security partitioning</li></ul>Alif Semiconductor is the only company in this market segment that injects at manufacturing, a unique public key infrastructure (PKI) key pair to support immutable&nbsp;hardware root of trust (RoT) from secure boot to strong authentication and remote software attestation capabilities.As a result, the personal data acquired by sensors and processed by the Alif Balletto microcontrollers are secured against third-party attacks.Users can securely manage all aspects of the device lifecycle, including key management, certificate management, remote updates, and more. Legacy MCUs may stop at TrustZone, but Alif takes you beyond TrustZone to ensure that multi-core devices are protected by not allowing two CPUs to access the same Secure domain and share secrets.&nbsp;<h3 dir="ltr">Graphics and imaging</h3>The Balletto family includes a number of hardware features to help offload traditionally CPU-intensive workloads from the MCU/MPU cores to improve performance and keep current consumption in check. One such feature is an integrated 2D graphics accelerator that can help speed up drawing operations by 4-10x compared to an unaccelerated system. This, combined with a set of imaging and display interfaces, which include parallel as well as MIPI-CSI2 and MIPI-DSI interfaces for 24-bit RGB displays and 8 to 16-bit cameras, provide everything needed for responsive and buttery-smooth graphics on pixel-dense screens.<h2 dir="ltr">Conclusion</h2>As the wearable technology market continues to expand, the convergence of edge AI and BLE technology has enabled wearables to become smarter, more efficient, and more secure. Alif Semiconductor's Balletto family of MCUs represents a significant leap forward in meeting the ever-growing demands of the wearables market. These innovative solutions empower wearables to not only collect and process data but also to provide real-time, personalized, and secure experiences, all while maintaining long-lasting battery life and optimizing form factor. The future of wearables is here, and it's exciting.<h3 dir="ltr">References</h3><ol><li dir="ltr">GlobeNewswire. <a href="https://www.globenewswire.com/en/news-release/2023/03/15/2627702/0/en/2023-2028-Smart-Wearables-Market-Size-Share-and-Trends-Analysis-Report-By-Y-O-Y.html" target="_blank">2023- 2028 Smart Wearables Market Size, Share and Trends Analysis Report By Y-O-Y</a>.</li><li dir="ltr">businesswire. <a href="https://www.businesswire.com/news/home/20220104005806/en/Global-Wearable-Technology-Market-Trends-Analysis-Report-2021-2028-Adoption-of-Fitness-Trackers-and-Health-based-Wearables-is-Anticipated-to-Propel-Growth---ResearchAndMarkets.com" target="_blank">Global Wearable Technology Market Trends &amp; Analysis Report 2021-2028: Adoption of Fitness Trackers and Health-based Wearables is Anticipated to Propel Growth - ResearchAndMarkets.com.</a></li></ol><h3>Further Research</h3>Ramesh Nair, 2023. “<a href="https://www.safetymint.com/blog/smart-wearables/" target="_blank">Smart Wearables: Advancing Safety in the Workplace</a>”StartUs Insights, 2023. “<a href="https://www.startus-insights.com/innovators-guide/wearables-trends/" target="_blank">Top 10 Wearables Trends in 2023</a>”GlobalData, 2022. “<a href="https://www.medicaldevice-network.com/comment/wearable-technology-iot/" target="_blank">Wearable technology market continues to rise</a>”Lisa Eadicicco, 2022. “<a href="https://www.cnet.com/tech/mobile/smartwatches-have-measured-blood-oxygen-for-years-but-is-it-useful/" target="_blank">Smartwatches Have Measured Blood Oxygen for Years. But Is This Useful?</a>”Fi Forest, 2022. “<a href="https://www.pharmaceutical-technology.com/sponsored/wearables-managing-complexities-data-privacy-consent/" target="_blank">Wearables: managing complexities in data privacy and consent in healthcare tech</a>”Industry News, 2022. “<a href="https://www.helpnetsecurity.com/2022/11/16/alif-semiconductor-telit/" target="_blank">Alif Semiconductor partners with Telit to develop and deploy IoT edge devices</a>”Alif Semiconductor, 2023. “<a href="https://alifsemi.com/ensemble/" target="_blank">Supplying next generation scalable microcontrollers</a>”Arrow, 2022. “<a href="https://www.arrow.com/en/research-and-events/articles/alif-semiconductor" target="_blank">Alif Semiconductor</a>”Eduardo Montanez, 2022. “<a href="https://www.nxp.com/company/blog/nxp-i-mx-rt-mcu-technology-powers-our-smartwatch-future:BL-NXP-IMX-RT-MCU-TECHNOLOGY" target="_blank">NXP i.MX RT MCU Technology Powers Our Smartwatch Future</a>”

Learn how bluetooth connected AI/ML microcontrollers are setting the bar for next generation wearables.

Leading Wearables into a New Era with Cutting-Edge Connected Bluetooth LE based MCUs

After a stroke, survivors often experience uncontrollable spasms that can twist their arms and hands into perpetual fists. The only treatments are expensive, frequently painful injections of botulinum toxin or oral medications so strong they may put patients to sleep. Both offer only temporary relief.Engineers at Stanford University and the Georgia Institute of Technology now say they have developed a glove-like wearable medical device that achieves as-good-or-better results as the injections or drugs by applying simple, high-frequency mechanical vibrations to the hands and fingers.“Vibration therapies are not unknown, so we knew we would see some effect, but clinically it was just amazing to see that these beneficial effects persist,” explained <a href="https://profiles.stanford.edu/allison-okamura" data-extlink="" target="_blank">Allison Okamura</a>, Richard W. Weiland Professor are the Stanford School of Engineering and senior author of a series of studies introducing the glove.“There are significant improvements in symptoms using the simulation method. And we think it can potentially address several effects of stroke — numbness, spasticity, and, for some, limited range of motion,” said <a href="https://neuroscience.stanford.edu/people/caitlyn-seim" data-extlink="" target="_blank">Caitlyn Seim</a>, a post-doctoral researcher in Okamura’s lab and initiator of the project. “We're most excited about treating spasticity because it affects so many people's quality of life and has such limited treatment options.”<h2>Form factor</h2>To the researchers’ knowledge this is the first effort to explore vibrotactile stimulation (VTS) technique at a wearable scale. State-of-the-art methods employ whole-body vibration using machines that are large, expensive, and require visits to the clinic for treatment.Patients in trials wore the VTS device three hours a day for eight weeks. Results were compared to the effectiveness of injections and oral medications. When measured, more than half of participants who receive regular botulinum injections had equal or better results with daily use of the VTS glove.“I think we can safely say that VTS is at least as good as injections and oral medicines,” Okamura said. “And it was exciting to see there is some maintenance of the improvements over time, though more study of that is needed.”The prototype device was first developed by Seim and colleagues at Georgia Tech as a tool to help people learn motor tasks such as typing or playing musical instruments via haptic guidance. The device was later studied as an interactive music exercise tool for people with partial spinal cord injuries, which led the team to the realization that haptic stimulation may be therapeutic on its own. Their unique wearable form factor makes a new paradigm in intensive stimulation therapy possible, since users can wear the gloves throughout the day.“We started to wonder if stimulation might also be a therapeutic tool for brain and spinal injury. It was very exciting,” Seim said.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1707898661498-vibrating-glove-helps-1.jpg" style="width: 766px;" class="fr-fic fr-dib">The VTS Glove on a patient’s hand. The team engineered and fabricated over 20 devices for this study in-house in Stanford labs. | Image courtesy of Andrew Brodhead<h2 id="isPasted">Notable results</h2>The latest version of the VTS device wraps around the wrist, palm, and fingers and includes motors that provide continual high-frequency stimulation to individual fingers as well as muscles in the hand and wrist. The vibrations are subtle and unobtrusive — similar to the intensity of a cell phone vibrating. Patients are free to go about their normal activities while wearing the device.Neurologically, the mechanisms underlying the symptom improvements are still being studied, but the team theorizes that the device is taking advantage of the brain’s remarkable plasticity — its ability to find new pathways in response to damage or dysfunction. They believe that the VTS vibrations can modulate out-of-control muscles and send neural signals from the muscles back to the brain where the signals re-train undamaged areas of the brain. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .“The brain is essentially relearning the ability to perceive touch and proprioception,” Seim said of the brain’s ability to feel and understand where and how the arm, hands, and fingers are positioned in three-dimensional space.In candid video testimonials, patients speak in glowing terms of their preference for VTS over injections and medication. Those same patients also say that the VTS glove is “pleasant” or at least “comfortable” to wear. VTS is non-invasive, inexpensive, and avoids the side effects of injections and muscle relaxants. Most promising of all, Seim notes that many patients in the trials reported they voluntarily reduced their use of oral medications and some even planned to forego quarterly botulinum injections in favor of the VTS glove &nbsp; &nbsp; .“This is the magic glove, it’s better than [botulinum],” said one patient after just two weeks using VTS. “My fingers and wrist are more relaxed. Before it was very difficult to straighten my fingers and now it’s a lot easier.”“I stopped my morning dose of [muscle relaxer] and now I want to stop taking my night dose because the glove is working and I don’t need it,” noted another patient after a similar two-week period.The hope may be shared as both researchers say they believe VTS might also prove effective in other brain injury-related motor conditions and diseases — areas the team is already pursuing as they explore stroke effectiveness.“There are currently 100 million people worldwide living with stroke,” Seim said. “As many as one third experience these paralyzing arm spasms. We targeted the largest-possible population first, but certainly other conditions are on our radar.”As of now, the VTS device is available only to patients in the clinical trial, and Okamura and Seim are gearing up for the next phases that will include additional clinical studies to understand the device’s long-term effectiveness and optimal design.To that end, the team recently received a considerable grant from the National Science Foundation’s Convergence Accelerator program to further develop the vibrotactile glove as a commercial product.“We think we have enough clinical study under our belt to know that VTS is a very safe, effective treatment,” Okamura said. “We'd love to start getting it out there as a publicly available therapy.”Okamura is also a member of&nbsp;<a href="http://biox.stanford.edu/" data-extlink="" target="_blank">Stanford Bio-X</a>, the&nbsp;<a href="https://humanperformance.stanford.edu/" data-extlink="" target="_blank">Wu Tsai Human Performance Alliance</a>, and the&nbsp;<a href="https://neuroinstitute.stanford.edu/" data-extlink="" target="_blank">Wu Tsai Neurosciences Institute</a>, and a faculty affiliate of the&nbsp;<a href="https://hai.stanford.edu/" data-extlink="" target="_blank">Institute for Human-Centered Artificial Intelligence (HAI)</a>.

Postdoctoral researcher Caitlyn Seim takes measurements with a participant in the clinical trial. | Image courtesy of Andrew Brodhead

For those with stroke, involuntary contractions of the hands and arms often follow. A simple, wearable vibrating glove may offer a more effective treatment.

Vibrating glove helps stroke patients recover from muscle spasms

This article was discussed in our <a href="https://www.wevolver.com/profile/the.next.byte" rel="noopener noreferrer" target="_blank">Next Byte podcast</a>.&nbsp;<iframe height="200px" width="100%" frameborder="no" scrolling="no" seamless="" src="https://player.simplecast.com/1e9bb08c-384a-4d12-983e-8af2e63c741b?dark=false" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe> The full article will continue below.<hr>MIT engineers have developed a small ultrasound sticker that can monitor the stiffness of organs deep inside the body. The sticker, about the size of a postage stamp, can be worn on the skin and is designed to pick up on signs of disease, such as liver and kidney failure and the progression of solid tumors.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzA3NzI0MzU5MjkzLU1JVC1TZWVpbmdTdGlmZm5lc3MtMDEtcHJlc3NfMC5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 766px;" class="fr-fic fr-dib">A small ultrasound sticker, worn on the skin, can monitor the stiffness of organs deep inside the body. The MIT-developed sensor could detect signs of disease such as liver and kidney failure, and the progression of solid tumors. Image: Courtesy of the researchersIn an <a href="https://science.org/doi/10.1126/sciadv.adk8426" target="_blank">open-access study appearing today</a> in Science Advances, the team reports that the sensor can send sound waves through the skin and into the body, where the waves reflect off internal organs and back out to the sticker. The pattern of the reflected waves can be read as a signature of organ rigidity, which the sticker can measure and track.“When some organs undergo disease, they can stiffen over time,” says the senior author of the paper, Xuanhe Zhao, professor of mechanical engineering at MIT. “With this wearable sticker, we can continuously monitor changes in rigidity over long periods of time, which is crucially important for early diagnosis of internal organ failure.”The team has demonstrated that the sticker can continuously monitor the stiffness of organs over 48 hours and detect subtle changes that could signal the progression of disease. In preliminary experiments, the researchers found that the sticky sensor can detect early signs of acute liver failure in rats.The engineers are working to adapt the design for use in humans. They envision that the sticker could be used in intensive care units (ICUs), where the low-profile sensors could continuously monitor patients who are recovering from organ transplants.“We imagine that, just after a liver or kidney transplant, we could adhere this sticker to a patient and observe how the rigidity of the organ changes over days,” lead author Hsiao-Chuan Liu says. “If there is any early diagnosis of acute liver failure, doctors can immediately take action instead of waiting until the condition becomes severe.” Liu was a visiting scientist at MIT at the time of the study and is currently an assistant professor at the University of Southern California.The study’s MIT co-authors include Xiaoyu Chen and Chonghe Wang, along with collaborators at USC.Sensing wobblesLike our muscles, the tissues and organs in our body stiffen as we age. With certain diseases, stiffening organs can become more pronounced, signaling a potentially precipitous health decline. Clinicians currently have ways to measure the stiffness of organs such as the kidneys and liver using ultrasound elastography — a technique similar to ultrasound imaging, in which a technician manipulates a handheld probe or wand over the skin. The probe sends sound waves through the body, which cause internal organs to vibrate slightly and send waves out in return. The probe senses an organ’s induced vibrations, and the pattern of the vibrations can be translated into how wobbly or stiff the organ must be.Ultrasound elastography is typically used in the ICU to monitor patients who have recently undergone an organ transplant. Technicians periodically check in on a patient shortly after surgery to quickly probe the new organ and look for signs of stiffening and potential acute failure or rejection.“After organ transplantation, the first 72 hours is most crucial in the ICU,” says another senior author, Qifa Zhou, a professor at USC. “With traditional ultrasound, you need to hold a probe to the body. But you can’t do this continuously over the long term. Doctors might miss a crucial moment and realize too late that the organ is failing.”The team realized that they might be able to provide a more continuous, wearable alternative. Their solution expands on an <a href="https://news.mit.edu/2022/ultrasound-stickers-0728" target="_blank">ultrasound sticker</a> they previously developed to image deep tissues and organs.“Our imaging sticker picked up on longitudinal waves, whereas this time we wanted to pick up shear waves, which will tell you the rigidity of the organ,” Zhao explains.Existing ultrasound elastrography probes measure shear waves, or an organ’s vibration in response to sonic impulses. The faster a shear wave travels in the organ, the stiffer the organ is interpreted to be. (Think of the bounce-back of a water balloon compared to a soccer ball.)The team looked to miniaturize ultrasound elastography to fit on a stamp-sized sticker. They also aimed to retain the same sensitivity of commercial hand-held probes, which typically incorporate about 128 piezoelectric transducers, each of which transforms an incoming electric field into outgoing sound waves.“We used advanced fabrication techniques to cut small transducers from high-quality piezoelectric materials that allowed us to design miniaturized ultrasound stickers,” Zhou says.The researchers precisely fabricated 128 miniature transducers that they incorporated onto a 25-millimeter-square chip. They lined the chip’s underside with an adhesive made from hydrogel — a sticky and stretchy material that is a mixture of water and polymer, which allows sound waves to travel into and out of the device almost without loss.In preliminary experiments, the team tested the stiffness-sensing sticker in rats. They found that the stickers were able to take continuous measurements of liver stiffness over 48 hours. From the sticker’s collected data, the researchers observed clear and early signs of acute liver failure, which they later confirmed with tissue samples.“Once liver goes into failure, the organ will increase in rigidity by multiple times,” Liu notes.“You can go from a healthy liver as wobbly as a soft-boiled egg, to a diseased liver that is more like a hard-boiled egg,” Zhao adds. “And this sticker can pick up on those differences deep inside the body and provide an alert when organ failure occurs.”The team is working with clinicians to adapt the sticker for use in patients recovering from organ transplants in the ICU. In that scenario, they don’t anticipate much change to the sticker’s current design, as it can be stuck to a patient’s skin, and any sound waves that it sends and receives can be delivered and collected by electronics that connect to the sticker, similar to electrodes and EKG machines in a doctor’s office.“The real beauty of this system is that since it is now wearable, it would allow low-weight, conformable, and sustained monitoring over time,” says Shrike Zhang,&nbsp;an associate professor of medicine at Harvard Medical School and associate bioengineer at Brigham and Women’s Hospital, who was not involved with the study. “This would likely not only allow patients to suffer less while achieving prolonged, almost real-time monitoring of their disease progression, but also free trained hospital personnel to other important tasks.”The researchers are also hoping to work the sticker into a more portable, self-enclosed version, where all its accompanying electronics and processing is miniaturized to fit into a slightly larger patch. Then, they envision that the sticker could be worn by patients at home, to continuously monitor conditions over longer periods, such as the progression of solid tumors, which are known to harden with severity.“We believe this is a life-saving technology platform,” Zhao says. “In the future, we think that people can adhere a few stickers to their body to measure many vital signals, and image and track the health of major organs in the body.”

“We used advanced fabrication techniques to cut small transducers from high-quality piezoelectric materials that allowed us to design miniaturized ultrasound stickers,” Xuanhe Zhao, professor of mechanical engineering at MIT, says. Image: Courtesy of the researchers

The sticky, wearable sensor could help identify early signs of acute liver failure.

This ultrasound sticker senses changing stiffness of deep internal organs

This article was discussed in our <a href="https://www.wevolver.com/profile/the.next.byte" rel="noopener noreferrer" target="_blank">Next Byte podcast</a>.&nbsp;<iframe height="200px" width="100%" frameborder="no" scrolling="no" seamless="" src="https://player.simplecast.com/c7a0deb3-ad50-40fa-8df2-1273193fb185?dark=false" class="fr-draggable" data-gtm-yt-inspected-9="true" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe> The full article will continue below.<hr> <iframe width="640" height="360" src="https://www.youtube.com/embed/pAWrypkeDXM?&amp;wmode=opaque&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" frameborder="0" allowfullscreen="" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true" data-gtm-yt-inspected-9="true" id="72780686" title="Soft robotic device improves walking for individual with Parkinson’s disease">&nbsp;&nbsp;</iframe>Freezing is one of the most common and debilitating symptoms of Parkinson’s disease, a neurodegenerative disorder that affects more than 9 million people worldwide. When individuals with Parkinson’s disease freeze, they suddenly lose the ability to move their feet, often mid-stride, resulting in a series of staccato stutter steps that get shorter until the person stops altogether. These episodes are one of the biggest contributors to falls among people living with Parkinson’s disease.&nbsp;Today, freezing is treated with a range of pharmacological, surgical or behavioral therapies, none of which are particularly effective.&nbsp;What if there was a way to stop freezing altogether?Researchers from the <a href="https://seas.harvard.edu/" target="_blank">Harvard John A. Paulson School of Engineering and Applied Sciences&nbsp;</a>(SEAS) and the <a href="https://www.bu.edu/sargent/" target="_blank">Boston University Sargent College of Health &amp; Rehabilitation Sciences</a> have used a soft, wearable robot to help a person living with Parkinson’s walk without freezing. The robotic garment, worn around the hips and thighs, gives a gentle push to the hips as the leg swings, helping the patient achieve a longer stride.&nbsp;The device completely eliminated the participant’s freezing while walking indoors, allowing them to walk faster and further than they could without the garment’s help.&nbsp;“We found that just a small amount of mechanical assistance from our soft robotic apparel delivered instantaneous effects and consistently improved walking across a range of conditions for the individual in our study,” said <a href="https://seas.harvard.edu/person/conor-walsh" target="_blank">Conor Walsh</a>, the Paul A. Maeder Professor of Engineering and Applied Sciences at SEAS and co-corresponding author of the study.&nbsp;The research demonstrates the potential of soft robotics to treat this frustrating and potentially dangerous symptom of Parkinson’s disease and could allow people living with the disease to regain not only their mobility but their independence.&nbsp;The research is published in <a href="https://www.nature.com/articles/s41591-023-02731-8" target="_blank">Nature Medicine.&nbsp;</a>For over a decade, Walsh’s<a href="https://biodesign.seas.harvard.edu/" target="_blank">&nbsp;Biodesign Lab&nbsp;</a>at SEAS has been developing assistive and rehabilitative robotic technologies to improve mobility for individuals’ post-stroke and those living with ALS or other diseases that impact mobility. Some of that technology, specifically an exosuit for post-stroke gait retraining, received support from the <a href="https://wyss.harvard.edu/" target="_blank">Wyss Institute for Biologically Inspired Engineering</a>, and was licensed and commercialized by <a href="https://rewalk.com/restore-exo-suit/" target="_blank">ReWalk Robotics</a>.In 2022, SEAS and Sargent College received a grant from the <a href="https://innovation.masstech.org/news/baker-polito-administration-awards-harvard-and-boston-university-3-million-assistive-robotics" target="_blank">Massachusetts Technology Collaborative</a><a href="https://masstech.org/" target="_blank">&nbsp;</a>to support the development and translation of next-generation robotics and wearable technologies. The research is centered at the <a href="https://www.movelab.seas.harvard.edu/" target="_blank">Move Lab</a>, whose mission is to support advances in human performance enhancement with the collaborative space, funding, R&amp;D infrastructure, and experience necessary to turn promising research into mature technologies that can be translated through collaboration with industry partners.This research emerged from that partnership.“Leveraging soft wearable robots to prevent freezing of gait in patients with Parkinson’s required a collaboration between engineers, rehabilitation scientists, physical therapists, biomechanists and apparel designers,” said Walsh, whose team collaborated closely with that of Terry Ellis, &nbsp;Professor and Physical Therapy Department Chair and Director of the <a href="https://www.bu.edu/neurorehab/" target="_blank">Center for Neurorehabilitation at Boston University.&nbsp;</a><blockquote>Leveraging soft wearable robots to prevent freezing of gait in patients with Parkinson’s required a collaboration between engineers, rehabilitation scientists, physical therapists, biomechanists and apparel designers.CONOR WALSHPAUL A. MAEDER PROFESSOR OF ENGINEERING AND APPLIED SCIENCES</blockquote>The team spent six months working with a 73-year-old man with Parkinson’s disease, who — despite using both surgical and pharmacologic treatments — endured substantial and incapacitating freezing episodes more than 10 times a day, causing him to fall frequently. These episodes prevented him from walking around his community and forced him to rely on a scooter to get around outside.&nbsp;In previous research, Walsh and his team leveraged human-in-the-loop optimization to demonstrate that a soft, wearable device could be used to augment hip flexion and assist in swinging the leg forward to provide an efficient approach to reduce energy expenditure during walking in healthy individuals. &nbsp;Here, the researchers used the same approach but to address freezing. The wearable device uses cable-driven actuators and sensors worn around the waist and thighs. Using motion data collected by the sensors, algorithms estimate the phase of the gait and generate assistive forces in tandem with muscle movement.The effect was instantaneous. Without any special training, the patient was able to walk without any freezing indoors and with only occasional episodes outdoors. He was also able to walk and talk without freezing, a rarity without the device.&nbsp;“Our team was really excited to see the impact of the technology on the participant’s walking,” said Jinsoo Kim, former PhD student at SEAS and co-lead author on the study.&nbsp;During the study visits, the participant told researchers: “The suit helps me take longer steps and when it is not active, I notice I drag my feet much more. It has really helped me, and I feel it is a positive step forward. It could help me to walk longer and maintain the quality of my life.”&nbsp;“Our study participants who volunteer their time are real partners,” said Walsh. “Because mobility is difficult, it was a real challenge for this individual to even come into the lab, but we benefited so much from his perspective and feedback.”&nbsp;The device could also be used to better understand the mechanisms of gait freezing, which is poorly understood.&nbsp;“Because we don’t really understand freezing, we don’t really know why this approach works so well,” said Ellis. “But this work suggests the potential benefits of a ’bottom-up’ rather than ’top-down’ solution to treating gait freezing. We see that restoring almost-normal biomechanics alters the peripheral dynamics of gait and may influence the central processing of gait control.”The research was co-authored by Jinsoo Kim, Franchino Porciuncula, Hee Doo Yang, Nicholas Wendel, Teresa Baker and Andrew Chin. Asa Eckert-Erdheim and Dorothy Orzel also contributed to the design of the technology, as well as Ada Huang, and Sarah Sullivan managed the clinical research. It was supported by the National Science Foundation under grant CMMI-1925085; the National Institutes of Health under grant NIH U01 TR002775; and the Massachusetts Technology Collaborative, Collaborative Research and Development Matching Grant.

Robotic exosuit eliminated gait freezing, a common and highly debilitating symptom

Soft robotic, wearable device improves walking for individual with Parkinson's disease

Multi-scale approach improves the fatigue threshold of particle-reinforced rubber

Rubber that doesn't grow cracks when stretched many times

Bike helmets that absorb the energy of an impact, running shoes that give you an extra boost with every step, or implants that behave just like natural bone. Metamaterials make such applications possible. Their inner structure is the result of a careful design process, following which 3D printers produce structures with optimised properties. Researchers led by Dennis Kochmann, Professor of Mechanics and Materials in the Department of Mechanical and Process Engineering at ETH Zurich, have developed novel AI tools that bypass the time-consuming and intuition-based design process of metamaterials. Instead, they predict metamaterials with extraordinary properties in a rapid and automated fashion. A novelty, their framework applies to large (so-called non-linear) loads, e.g. when a helmet absorbs major forces during an impact.Kochmann’s team has been among the pioneers in designing small-scale cellular structures (similar to beam networks in timber-frame houses) to create metamaterials with specific or extreme properties. “For example, we design metamaterials that behave like fluids: hard to compress but easy to deform. Or metamaterials that shrink in all directions when compressed in a particular one,” explains Kochmann.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzAyNTEzMjEwOTY4LWltYWdlLmltYWdlZm9ybWF0LjEyODYuMTAzOTA5ODg1NC5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 766px;" class="fr-fic fr-dib">While the forward challenge of predicting properties is relatively well understood, finding microstructures for target properties is much harder (inverse design). (Illustration: ETH Zurich / Dennis Kochmann)<h2 id="isPasted">Efficient, optimal material design&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</h2>The design possibilities seem endless. However, the full potential of metamaterials is far from realised, since the design process is based on experience, involving trial and error. Furthermore, small changes in the structure can give rise to huge changes in properties.In their recent breakthrough, the researchers succeeded in using AI to systematically explore the abundant design and mechanical properties of two types of metamaterials. Their computational tools can predict optimal structures for desired deformation responses at the push of a button. Key is the use of large datasets of the deformation behaviour of real structures to train an AI model that not only reproduces data but also generates and optimises new structures. By leveraging a method known as “variational autoencoders”, the AI learns the essential features of a structure from the large set of design parameters and how they result in specific properties. It then uses this knowledge to generate a metamaterial blueprint whenever the researchers specify its desired properties and requirements.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzAyNTEzMjcwOTQ4LWltYWdlLmltYWdlZm9ybWF0LmxpZ2h0Ym94Ljg1MDM1NDE5OS5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 766px;" class="fr-fic fr-dib">The structure of a metamaterial is encoded in an abstract space. Optimisation efficiently improves the design towards the desired properties. A decoder turns the optimised design into a real-world truss structure. (Illustration: ETH Zurich / Li Zheng)<h2 id="isPasted">Assembling building blocks&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;</h2>Li Zheng, a doctoral student in Kochmann’s group, trained an AI model using a dataset of one million structures and their simulated response. “Imagine a huge box of Lego bricks – you can arrange them in countless ways and over time learn design principles. The AI does this extremely efficiently and learns essential design features and how to assemble the building blocks of metamaterials to give them a particular softness or hardness”, says Zheng. Unlike prior approaches using a small catalogue of building blocks as the basis for design, the new method gives the AI freedom to add, remove, or move building blocks around almost arbitrarily. Together with Sid Kumar, an assistant professor at TU Delft and a former member of Kochmann’s team, they showed in a recently published paper that the AI model can even go beyond what it has been trained to do and predict structures that are far better than anything ever generated before.<h2>Learning from the movies</h2>Jan-Hendrik Bastek, also doctoral student in Kochmann’s group, used a different approach to achieve something similar. He used a method originally introduced for AI-based video generation, which has become commonplace: if you type in ‘an elephant flying over Zurich’, the AI generates a realistic video of an elephant circling the Fraumünster Church. Bastek trained his AI system using 50,000 video sequences of deforming 3D-printable structures. “I can insert the trajectory of how I want the structures to deform, and the AI produces a video of the optimal structure and the complete deformation response,” explains Bastek. Most previous approaches have focused on only predicting a single image of the optimal structure. However, giving the AI videos of the entire deformation process is crucial to retain accuracy in such complex scenarios. Based on the video sequences, the AI can create blueprints for new materials, taking into account highly complex scenarios.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1702513523867-ezgif-2-8c2d523d04.gif" style="width: 300px;" class="fr-fic fr-dib">Video diffusion iteratively converts pure noise into meaningful data, such as pixels representing a metamaterial being deformed in a specific way, here illustrating the stress distribution inside the material. (Video: ETH Zurich / Jan-Hendrik Bastek)<h2 id="isPasted">Big benefits for bike helmets and shoe soles</h2>The researchers have made available their AI tools to the metamaterials community. This will hopefully lead to the design of many new and unusual materials. The tools are opening new avenues for the development of protective equipment such as bicycle helmets and for further applications of metamaterials from medical engineering to soft robotics. Even shoe soles can be designed to absorb shocks better when running or to provide a forward boost when stepping down. Will AI completely replace the manual engineering design of materials? “No,” laughs Kochmann. “Used well, AI can be a highly efficient and diligent assistant, but it must be given the right instructions and the right training – and that requires scientific principles and engineering knowhow.”<hr><h2 id="isPasted">Reference</h2>Bastek JH, Kochmann DM: Inverse design of nonlinear mechanical metamaterials via video denoising diffusion models. Nature Machine Intelligence 2023, doi: <a href="https://doi.org/10.1038/s42256-023-00762-x" target="_blank">external page10.1038/s42256-023-00762-x</a>Zheng L, Karapiperis K, Kumar S, Kochmann DM: Unifying the design space and optimizing linear and nonlinear truss metamaterials by generative modeling. Nature Communications 2023, 14: 7563, doi: <a href="https://doi.org/10.1038/s41467-023-42068-x" target="_blank">external page10.1038/s41467-023-42068-x</a>

Conceptualisation of a running shoe made out of a metamaterial. AI generated with DALL-​E   (Visualisation: ETH Zurich)

Researchers have trained an artificial intelligence to design the structure of so-​called metamaterials with desired mechanical properties for a wide range of applications.

Artificial intelligence for safer bike helmets and better shoe soles

<section id="isPasted">The first glucose self-monitoring system created in 1970 weighed three pounds, was initially designed only for physicians’ offices and needed a large drop of blood for a reading. Over 50 years later, researchers at Texas A&amp;M University are working to create a fully injectable continuous glucose monitor (CGM) so small it rivals a grain of rice and can be used with an external optical reader to measure sugar levels at any given time.While CGMs have advanced over the last 25 years, current models can still be a nuisance to the user and the required upkeep may discourage use. To address this issue, two faculty members from the Department of Biomedical Engineering have received a National Science Foundation (NSF) grant to fund a multidisciplinary project to develop an injectable, grain-of-rice-sized glucose biosensor and wearable device enabling user-friendly, minimally-invasive continuous monitoring.“CGMs are commercially available, but most of them are indwelling, meaning there is a needle in the skin connected to a patch on the arm,” co-principal investigator and Regents Professor Dr. Gerard Coté said. “There is one CGM that is totally implantable, but it is much bigger than ours and requires a doctor to surgically implant it with an incision.”The NSF grant is backed by the biosensing program, a part of the engineering biology and health cluster of the NSF Chemical, Bioengineering, Environmental and Transport Systems (CBET) Division. The division aims to support trailblazing research and education in these areas.<h2>Using autofluorescence to read blood sugar&nbsp;</h2>Coté and his lab are designing the injected sensor’s chemistry and developing the watch-type reader device. The sensor is put under the skin and analyzed using light from the watch-like device to determine the glucose concentration. The reader sends the signal to a cell phone and the patient can share the results with their health provider.“The chemical assay in the injectable sensor is used to determine the concentration of the glucose within the tissue, and the watch device sends in light and measures the fluorescence from the sensor to give the sugar concentration,” Coté said.Aside from its unique size and injectability, the sensor and wearable reader employ an optical sensing technology that addresses the challenges associated with biosensing for populations of darker skin tones.&nbsp;“We use chemistry that has a fluorescent color that emits in the red and infrared range rather than green light, which works better for the darker skin tones,” Coté said.</section><section><h2>Protecting the sensor</h2>Co-principal investigator Dr. Melissa Grunlan, Charles H. and Bettye Barclay Professor in Engineering, is working with her lab to wrap the sensing chemistry in a membrane that makes it more compatible within the body.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1701821831800-BMEN-news-biosensor-sleeve-16Nov2023.jpg" style="width: 300px;" class="fr-fic fr-dib">The size and injectability of the biosensor makes for a less invasive method of monitoring blood glucose. | Image:&nbsp;<cite id="isPasted">Courtesy of Dr. Melissa Grunlan</cite>“When you implant something, the body thinks, ‘This does not belong here,’ and it tries to seal it off,” Grunlan said. “When that happens, that sensor can't work because there's no glucose getting into it. Our membrane is a hydrogel, similar to the material used for contact lenses, but this is a special hydrogel that is thermoresponsive.”The thermoresponsive nature allows the sensor to sit subtly in the body. The surface actively swells and shrinks just enough to keep cells and proteins from sticking to the sensor and forming obstructive scar tissue around it.Grunlan and Coté recently had a patent issued on the membrane technology and are considering different devices it could be used with, particularly to sustain the lifetime of medical devices.“The membrane could be applied to assorted devices that are prone to adhesion processes in the body,” Grunlan said. “It could be used on maybe a catheter to prevent thrombosis and infection by preventing the accumulation of proteins, cells, and organisms.”<h2>Multidisciplinary research in biomedical engineering</h2>The project culminates nearly two decades of research and collaboration between Coté’s biosensing expertise and Grunlan’s biomaterial expertise.“Working together as a team with complementary expertise is the key to developing complicated technologies such as this one,” Coté said. “Being able to collaborate with an expert like Dr. Grunlan in designing and developing biocompatible materials and bringing our experience in optical biosensor design is needed and gives us hope for success.”Although the grant is new funding, Grunlan and Coté have been preparing for this stage of their project for some time now and feel confident in the device’s outcome.“Dr. Coté and I have done extensive research in the past together that has led up to this study and this particular grant,” Grunlan said. “We've done some preclinical studies to assess the membrane's biocompatibility. He's done extensive work developing the sensing chemistry. What’s great about this grant is now we can prove our idea, and we’re in a really good position to do that.”</section>

Researchers receive funding to develop injectable grain-of-rice-sized continuous glucose monitor technology.

Miniature Device Offers Peace of Mind for Diabetics

E-textiles are worn close to and/or against the surface of the skin, with applications in healthcare, gaming, athletic training and environmental monitoring. Thanks to embedded electronic components, e-textiles can store and harvest energy, sense, display, actuate and compute.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1698479495630-resizedcamdrawing1.png" style="width: 768px;" class="fr-fic fr-dib">Illustration showing the 4R design concept: repair; recycle; replace; reduce. Credit: Dr Harvey ShiYet there are two major challenges to the future growth of e-textiles: firstly, high costs, therefore resulting in slower consumer adoption. Secondly, high environmental costs associated with mass production, in particular, <a href="https://portals.iucn.org/library/sites/library/files/documents/2017-002-En.pdf" target="_blank" data-lf-fd-inspected-kn9eq4roawkarlvp="true">microplastic water pollution</a>. Fundamentally, we need new ways to prevent the scale-up of e-textiles from becoming the next electronic waste (e-waste) environmental fiasco.This is according to a team of engineers and scientists from the UK, Canada, the USA and China, led by the University of Cambridge, who warn that the e-textile supply chain and its potential for scalable commercialisation could be “further complicated” by the associated global environmental burden, and the growing use of nanomaterials in e-textiles. They say that some of these nanomaterials can pose environmental challenges and could also have adverse effects on human health (e.g. skin irritation and/or absorption of loose nanoparticles into the skin).<a href="https://doi.org/10.1038/s41563-023-01615-z" target="_blank">Writing in the journal</a> Nature Materials, the research team proposes the 4R e-textile design concept (repair; recycle; replace; reduce) alongside innovations in materials selection and biofabrication-inspired processing – a revolutionary approach that uses additive manufacturing processes to produce biomaterials, devices, cells and tissues. The aim is to reach sustainable growth and balance economic returns/scalable commercialisation with “environmental consciousness”, at a time when <a href="https://www.mckinsey.com/industries/retail/our-insights/survey-consumer-sentiment-on-sustainability-in-fashion" target="_blank">consumers are actively aligning their purchasing behaviours with sustainability goals</a>.The 4Rs for more affordable, versatile e-textiles products and enhanced supply chains have been defined as follows:<h3>Repair</h3>‘Fibre level’ repairs e.g. resewing, reweaving, reknitting and self-healing of electronic fibres, and bulk ‘fabric-level’ repairs e.g. recoating, reprinting and respraying of active materials.Eventually, the e-textile materials would adopt self-healing mechanisms, which would give them the capability of self-repair over time. Also, with a modular approach to future e-textile designs, it is also possible to switch out faulty components easily and rejuvenate the electronic functionalities of the system.<h3>Recycle</h3>In the near term, recycling can be encouraged by categorising and separating e-textiles components into the base textile and the electronic modules.The base textile can be recycled as regular clothing and the electronic components recycled as regular e-waste streams.However, e-textile recycling becomes more complex when the fabrics contain, for example, functionalised electronic fibres with electrical conductivity and sensing capabilities. Extraction in most cases would be time-consuming and costly, say the researchers, so reusing and repurposing used functional components might be a viable option.<h3>Replacement</h3>The research team also notes&nbsp;that while biomass fibres such as those extracted from wool, silk, cellulose, flax and hemp, could provide a renewable source for e-textile production, this is not often possible. This is due to the fact that nano- and microstructured active coatings and functionalised strategies need to be applied to enable electronic functions, that would otherwise be missing. Therefore, novel materials design that utilises earth-abundant elements can accelerate e-textile commercialisation and make them more cost-effective for the average consumer.Additionally, the research team also calls for alternative bioderived material options for electronic fibre encapsulation to create non-irritating and skin-compatible e-textile surfaces. Currently, material options are mostly synthetic and non-biodegradable.<h3>Reduction</h3>This, according to the researchers, can be interpreted in two ways:<ol><li>Reducing the total emissions and energy consumption during e-textile production and deployment.</li><li>Reducing the total amount of material used in e-textiles to achieve and maintain a specified function.</li></ol>“Currently, the scalable commercialisation of e-textiles products is limited by high pricing and lack of diversity, durability and washability,” said co-lead author <a href="http://www.eng.cam.ac.uk/profiles/yysh2" target="_blank">Professor Shery Huang</a> from Cambridge’s Department of Engineering. “This is why materials considerations in the 4R realm (identified as repair; recycle; replace; reduce) need to be addressed in order to secure a sustainable future for e-textiles development.”“Machine washing of e-textiles has, to date, contributed to an increase in microplastic pollution in the water stream. The challenge here is to reinforce the functional longevity of e-textiles, while minimising the number of microparticles released. Strategies for this include the decoupling of transient/single-use components or designing ‘dry’ or ‘vapour-based’ cleaning protocols that consume less water,” said co-lead author Dr Harvey Shi from Western University, Canada.The research team has proposed various sustainable e-textile strategies. For example, an e-textile can be divided as “canvas” and “modules” components. The “canvas” is machine-washable and provides the bulk of the user’s sensory experience, while the “modules” are the interconnected components that carry electronic functionalities.The researchers&nbsp;say that the “canvas” should be designed to maintain reliability as an electrically insulating and chemically inert medium under persistent use and occasional reconfiguration. The “modules” meanwhile, can be designed with various formats to be easily removable and replaceable, so that their electronic functions can be maintained for long-term use.The “canvas” and “modules” can be sorted by three preliminary lifespan ratings: quasi-permanent, with a lifespan of approximately one year; multiple use, with a lifespan ranging from weeks to months; and single-use.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1698479511172-CENTRE_CamDrawing2.png" style="width: 766px;" class="fr-fic fr-dib">Illustration showing the marriage of 4R concepts with functional fibre production/digital additive manufacturing and biofabrication techniques. Credit: Dr Harvey Shi.According to the researchers, the timeline for 4R-integrated e-textiles development can be broken down into the following:In the near term – standardising e-textiles platforms to integrate a variety of electronic modules, leading to innovative processing technologies and industrial standardisation that will bring affordable e-textiles to a broader consumer base.Further developments include: automated assembly processes; a database of functional ink formations for e-textiles developers to use; and establishing standardisation in component decoupling based on longevity ratings – a move that also effectively minimises the release of electronic micro- or nanoparticles into the water stream.<a href="https://www.graphene.cam.ac.uk/people/yifei-pan" target="_blank">Yifei Pan</a>, PhD student in the&nbsp;<a href="https://biointerface.eng.cam.ac.uk/" target="_blank">Biointerface Research Group</a> at Cambridge, said: “Adopting this standardisation approach in the near term can enable developers to create a customised array of cross-compatible functional components; reinforce user safety and public interests in the personalised healthcare and customised non-invasive therapeutics market (i.e. product certification); and can lead to designated cleaning protocols.”In the mid-term – employing user-centric design strategies and innovative processing technologies to offer a broader range of e-textiles to the public, ones that are comfortable to wear and which can be personalised to the user.“This is the point at which self-healing/self-repairing fibres can be achieved through molecular design and without the need for human intervention,” said Dr Shi. “This would effectively create a repairable e-textile ecosystem, in which the product can be readily disassembled and refurbished without adding to the environmental burden.”In the long term – sustainable and ‘living’ e-textiles can be realised, such as engineered robotic skin. Biohybrids, fibre-on-demand and biofabrication technologies will enable these e-textiles to self-clean (thus minimising the requirements for machine washing or solvent-based cleaning), self-repair and be capable of self-regeneration in the future.“In summary, the road towards ‘green’, biohybrid and circular fabrication calls for the marriage of our 4R concepts with functional fibre production/digital additive manufacturing and biofabrication to produce highly customisable e-textile designs,” said <a href="http://www.eng.cam.ac.uk/profiles/th270" target="_blank">Professor Tawfique Hasan</a> from the&nbsp;<a href="http://www.graphene.cam.ac.uk/" target="_blank">Cambridge Graphene Centre</a>.Professor Huang added: “As we drive towards future sustainable e-textile manufacturing, there could be a paradigm shift from a centralised mass production strategy with one principal facility to a more widespread additive manufacturing/3D printing platform – ultimately creating and repairing e-textiles on-site.”Reference: HaoTian Harvey Shi; Yifei Pan; Lin Xu; Xueming Feng; Wenyu Wang; Prasad Potluri; Liangbing Hu; Tawfique Hasan; Yan Yan Shery Huang. ‘<a href="https://doi.org/10.1038/s41563-023-01615-z" target="_blank">Sustainable electronic textiles towards&nbsp;scalable commercialization</a>’. Nature Materials (2023). DOI: 10.1038/s41563-023-01615-z

If electronic textiles (e-textiles) are to have a sustainable future and at scale, then a transition is needed to unlock innovative wearable e-textiles that fit a sustainable circular economy – adopting what has been termed as the 4R design concept: repair; recycle; replace; reduce.

Innovative wearable e-textiles fit for a sustainable circular economy

This article originally appeared in <a href="https://www.caltech.edu/about/news/wearable-patch-wirelessly-monitors-estrogen-in-sweat" target="_blank" rel="noopener noreferrer">Caltech</a> and has been republished with permission.<hr>The sex hormone commonly known as estrogen plays an important role in multiple aspects of women's health and fertility. High levels of estrogen in the body are associated with breast and ovarian cancers, while low levels of estradiol can result in osteoporosis, heart disease, and even depression. (Estrogen is a class of hormones that includes estradiol as the most potent form). Estradiol is also necessary for the development of secondary sexual characteristics in women and regulates the reproductive cycle.Because of its many functions, the hormone estradiol is often specifically monitored by physicians as part of women's health care, but this usually requires the patient to visit a clinic to have blood drawn for analysis in a lab. Even at-home testing kits require samples of blood or urine to be mailed to a lab.But now Caltech researchers have developed a wearable sensor that monitors estradiol by detecting its presence in sweat. The researchers say the sensor may one day make it easier for women to monitor their estradiol levels at home and in real time.The research was conducted in the lab of <a href="https://www.eas.caltech.edu/people/weigao" target="_blank">Wei Gao</a>, assistant professor of medical engineering, investigator with the Heritage Medical Research Institute, and Ronald and JoAnne Willens Scholar. In recent years, Gao has developed sweat sensors that detect <a href="https://www.caltech.edu/about/news" target="_blank">cortisol</a>, a hormone associated with stress; the presence of the <a href="https://www.caltech.edu/about/news" target="_blank">COVID-19 virus</a>; a biomarker <a href="https://www.caltech.edu/about/news" target="_blank">indicating inflammation</a> in the body; and a whole slew of other nutrients and biological compounds.Gao says the development of the estradiol sensor was spurred in part by requests from people who were unsatisfied with the options they had for monitoring their estrogen levels and had seen his previous work."People often ask me if I could make the same kind of sweat sensor for female hormones, because we know how much those hormones impact women's health," Gao says.One population of women who would benefit from estradiol monitoring are those who are attempting to conceive a child, either naturally or through in vitro fertilization. The success of either method is dependent on getting timing right with regards to ovulation, but not all women have a reproductive cycle that follows a regular schedule. Some women have been able to track their ovulation by monitoring their body temperature, but Gao says that method has limited usefulness because it's not very accurate and body temperature doesn't increase until ovulation has begun."But estrogen increases before ovulation," he says. "With this sweat sensor, we would be able to give people notice ahead of time."Other individuals who could benefit from a wearable estrogen sensor are those undergoing hormone replacement therapy (HRT) because their bodies do not produce sufficient estradiol. In these patients, estradiol levels need to be carefully monitored to ensure they are taking the correct dosage.The sensor Gao's team developed is similar in many ways to the various sensors developed by the group in the past. It is built on a flexible plastic membrane; has tiny etched passages (microfluidics) for channeling small amounts of sweat into the sensor; and inkjet-printed gold nanoparticles and titanium carbide films (known as MXenes) that give the sensor a large surface area and electrical conductivity to increase its sensitivity.The primary challenge, and what dictated changes in the sensor's design this time around, is that estradiol, which already is present at fairly low levels in the blood, is roughly 50 times less concentrated in sweat."Since it's such a low concentration, it's very challenging to detect estradiol automatically in sweat," Gao says.For the new sensor, the research team made use of short single-stranded DNA known as aptamers. Aptamers work as artificial antibodies and are designed to bind specifically to a target molecule. The aptamers are attached to a surface modified with gold nanoparticles and bind to single-stranded DNA molecules tagged with a molecule that can directly donate or accept electrons under certain conditions. When an aptamer binds to an estradiol molecule, it releases the redox molecule. That molecule is recaptured by a nearby electrode made of MXene-coated gold nanoparticles, generating an electrical signal that correlates with the estradiol level. That hardware then wirelessly transmits the data it collects to an app that runs on a smart phone, providing a simple interface for the user.<iframe width="640" height="360" src="https://www.youtube.com/embed/XOvhMvg6Wfg?&amp;wmode=opaque&amp;rel=0&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" frameborder="0" allowfullscreen="" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true">&nbsp;</iframe>Another innovation in this device was the design of the microfluidics that collect sweat and channel it into the sensor. Tiny automatic valves incorporated in the microfluidics allow only a small, fixed amount of sweat into the sensor and then prevent additional sweat from entering. The design enables stable estradiol analysis without additional sweat disturbing the process. Moreover, to account for difference in sweat composition, the device also collects information about sweat pH, sweat salt levels, and skin temperature, and uses them for real-time calibration.Testing in the laboratory has shown that the sensor can reliably and accurately track the changing levels of estradiol in sweat over the course of the reproductive cycle, from the lowest level during menstruation to its highest level (10 times greater) during ovulation.Gao says he plans to continue working on this technology to allow it to monitor other female hormones, like luteinizing hormone or progesterone, which are both involved in ovulation. He also hopes to miniaturize all these sensors so they could all fit inside of a small wearable device such as an inconspicuous ring that can be worn on the finger.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1697198852920-Wei-Gao-Sweat-Sensor-to-Monitor-Estrogen-Lev.max-500x500.jpg" style="width: 766px;" class="fr-fic fr-dib">The sensor, if further miniaturized, could be worn discretely inside a ring, researchers say. Credit: CaltechThe paper describing the research, "<a href="https://www.nature.com/articles/s41565-023-01513-0" target="_blank" id="isPasted">A wearable aptamer nanobiosensor for non-invasive female hormone monitoring</a>," appears in the Sept. 28 issue of Nature Nanotechnology. Co-authors are postdoctoral scholar research associates in medical engineering Cui Ye, Minqiang Wang, and Juliane R. Sempionatto; medical engineering graduate students Jihong Min (MS '19), Heather Lukas (MS '21), Jiahong Li (MS '23), and Changhao Xu (MS '20); and Roland Yingjie Tay, formerly of Caltech and now with Nanyang Technological University of Singapore.

Caltech researchers have developed a wearable sensor that monitors estradiol by detecting its presence in sweat. The researchers say the sensor may one day make it easier for women to monitor their estradiol levels at home and in real time.

Wearable Patch Wirelessly Monitors Estrogen in Sweat

Andrew Stemmerman &amp; John Yundt SunRay Scientific Inc. Eatontown, NJ USA <a rel="noopener noreferrer" href="mailto:andrew@sunrayscientific.com" target="_blank">andrew@sunrayscientific.com</a> <a rel="noopener noreferrer" href="mailto:johny@sunrayscientific.com" target="_blank">johny@sunrayscientific.com</a>SunRay Scientific of Eatontown, NJ, USA has developed a new and innovative approach to electronic component assembly.&nbsp;This article will outline the developments of this technology and show examples of this magnetically aligned Anisotropic Conductive Epoxy packaging method used on various substrates. Progress will be shared for dense and fine pitch Land Grid Arrays (LGA) on a semi-rigid interposer.<h3>Introduction</h3>Flip-chip die and die-to-die bonding, from dense to fine pitch, typically require solder balls and underfills. Underfill and/or edge encapsulant is often utilized to provide additional mechanical strength and stress reduction. The result is a complex assembly process flow. Localized placement of Anisotropic Conductive Adhesive (ACA) or Anisotropic Conductive Film (ACF) for specific components typically involves the fine-pitchuse of thermocompression bonding, an additional process step that could also be damaging to thin silicon. Another drawback for traditional interconnect materials is relatively slow processes, limiting the utility of such technologies. Development towards a wafer scale compatible packaging method will be shared, using a pressure-less and low-temperature magnetically aligned Anisotropic Conductive Epoxy (ACE).<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk3MTAzNDM5ODc4LUZpZyAxLnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 525px;" class="fr-fic fr-dib"><figcaption data-pm-slice='1 1 ["figureImage",null]' id="isPasted">Figure 1. Flip Chip assembly comparisons: traditional solder balls &amp; underfill attachment (Left); Die attach with z-axis magnetically aligned conductive epoxy (Right)</figcaption>A summary of the novel approach is shown above in Figure 1. First, ferro-magnetic particles dispersed within an epoxy are coated onto a substrate. The ferro-magnetic particles form z-axis magnetically aligned columns, fixed in place during the die-to-substrate cure process without any pressure applied. The formation of the columns during the curing process is illustrated in Figure 2. This technology simplifies the assembly process to a single adhesive application, which provides both electrical interconnection and mechanical reinforcement. No additional underfill material is needed. Fine patterning is not required as the entire area of the component target location is deposited with epoxy. The device alignment process is more.forgiving relative to solder ball-to-solder pad alignment. Z-axis columns align after component placement, magnetic pallet exposure and cure is achieved.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk3MTAzNDc0MDUyLUZpZyAyLnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 378px;" class="fr-fic fr-dib"><figcaption data-pm-slice='1 1 ["figureImage",null]' id="isPasted">Figure 2. X-Ray photos of Z-axis magnetically aligned particles ferromagnetic in an Anisotropic Conductive Epoxy (ACE)</figcaption><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1699453964933-B-and-B-2024%28e-mail%29.jpg" style="width: 739px;" class="fr-fic fr-dib">Join us in Berlin and/or Boston and lets us RESHAPE the Future of Electronics, making it Additive, Sustainable, Hybrid, Wearable, and 3D - techblick.comThermal or UV curing methods complete the component attachment without any thermocompression (cure method is epoxy formulation dependent). Thermal curing occurs within the 80°C to 160°C temperature range.This article outlines the developments of this technology and shows examples of this magnetically aligned Anisotropic Conductive Epoxy packaging method used on various substrates. Progress will be shared for dense and fine-pitch Land Grid Arrays (LGA) on a semi-rigid interposer. Additionally, advancements made for die-to-die bonding will be presented as well as updates towards achieving ≤ 60-micron pitch. Other proposed direct die-attach packaging concepts will be illustrated.Example #2 covers development work performed on attaching a 126-pin Land Grid Array (LGA) bare die to a polymer semi-rigid multi-layer substrate. The use of the substrate resulted in multiple challenges for bare die attach. The non-planarity of the conductive circuit pads was one issue. The electrical resistance variation between pads had to be minimized for optimum performance. The non-uniformity of the substrate’s conductor pads is evident in the photo on the left. The schematic on the right illustrates how the ACE material allows for “leveling” in connecting the bare die to the non-planar substrate.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk3MTAzNTE3Njg5LUZpZyAzLnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 584px;" class="fr-fic fr-dib"><figcaption data-pm-slice='1 1 ["figureImage",null]' id="isPasted">Figure 3. 126-pad semi-rigid substrate (Left) and illustration of bond between die and substrate</figcaption>Additional learning during this work was in identifying trapped moisture within the polymer-based substrate as a cause for voids in the ACE during cure. These bubbles not only prevented connection in some cases but interfered with proper z-axis column formation. Prebake for the substrate was added as a step for this particular type of assembly.Two formulations were the focus of the work in Example #3. These were the Fine particles ACE and the Ultra Fine particles version. Stencil thicknesses of 0.001” to 0.005” were studied, as this tool has the most impact on establishing bond line thickness. The target for choosing the best formulation, tool and bond line thickness was lowest average resistance values with lowest deviation among the 126 pads. Iterative testing was done. “Heat maps” based on the 126 pad locations were created to visually observe resistance values within set target and acceptance ranges. The next two Figures show results from early work on process development with each epoxy formulation and stencil tools, to the progress made with the final choices on material and stencil thickness. Ultimately the Ultra Fine particles ACE with a 0.001” thick stencil was chosen for this LGA-to-substrate assembly application. Summary Table 1 shows the results of the chosen ACE and stencil, and Figure 6 is a cross-section from the development study.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk3MTAzNTQwNDg0LUZpZyA0LnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 598px;" class="fr-fic fr-dib"><figcaption data-pm-slice='1 1 ["figureImage",null]' id="isPasted">Figure 4. Pad-by-pad resistance measurement studies, early iteration (Left: Ultrafine, Right: Fine)</figcaption><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk3MTAzNTcyMzk5LUZpZyA1LnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 601px;" class="fr-fic fr-dib"><figcaption data-pm-slice='1 1 ["figureImage",null]' id="isPasted">Figure 5.&nbsp;Pad-by-pad resistance measurement studies, final iteration (Left: Ultrafine, Right: Fine)</figcaption>Table 1.&nbsp;Summary of performance metrics (continuity, resistance &amp; deviation, pad-to-pad)<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk3MTAzNjAwNzk0LVRhYmxlIDEucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 564px;" class="fr-fic fr-dib"><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk3MTAzNjIyODMyLUZpZyA2LnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 559px;" class="fr-fic fr-dib"><figcaption data-pm-slice='1 1 ["figureImage",null]' id="isPasted">Figure 6. Cross-section of component attached and electrically connected with the Z-axis ACE (Photo courtesy of Rochester Institute of Technology)</figcaption>Example #2 takes the LGA and Substrate subassembly to the next level, a large area 8” x 10” circuit board populated with four of the subassemblies plus components of various sizes and function. This larger assembly involves attaching all the multiple components and subassemblies in one ACE attachment process. Passives range in size from as small as 0201 up to 2220. Other devices are a 26-pin SMT connector and SoICs. This project is underway, and results will be shown by SunRay at TechBlick live in October.Fine-pitch die-to-die bonding with the ACE is the third example. The development methodology is like the other projects. An initial focus was on measuring continuity and resistance at pad sites as part of identifying the optimum process parameters and stencil tool for this application. The degree of difficulty is greater with finer pitch. Dense arrays of 60 microns pitch die, with 30 microns pads and 30 microns spacing, were used.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1699454054997-B-and-B-2024%28blog%29.jpg" style="width: 761px;" class="fr-fic fr-dib">Join us in Berlin and/or Boston and lets us RESHAPE the Future of Electronics, making it Additive, Sustainable, Hybrid, Wearable, and 3D - techblick.comA Design of Experiments (DoE) was established for the stencil studies. Laser profilometry was used for 3D and 2D scans of the two surfaces to be bonded, as was employed for observing the non-planarity of the semi-rigid board in Example #1. All initial steps were done manually: hand stencil printing, die placement with die bonder, batch oven cure and electrical probing.Prior to using fully functional devices, Quartz substrates patterned with the top layer of each die in the bond pair, were procured and used in early studies. The purpose was to provide enhanced analysis of the bonded die pair before, during, and after bonding/curing has occurred. Bond parameters were observed at each step of the process: pre-bond, bond, and post alignment &amp; cure.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk3MTAzNjk2MDIyLUZpZyA3LnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 624px;" class="fr-fic fr-dib"><figcaption data-pm-slice='1 1 ["figureImage",null]' id="isPasted">Figure 7. Left: Target overlay of quartz substrates; Middle: ACE deposit before bond; Right: Post-bond, before z-axis alignment and cure</figcaption>Due to the finer pitch requirements, the test vehicles have a nickel layer applied during wafer fabrication, at the bond pad locations. Past experimentation, as pictured in Figure 8, has shown nickel application may lower the resistance of the bonded circuit by directing column formation to the metallized bond pad boundary, the nickel pads, acting as localized magnets, attract column formation during exposure to the magnetic pallet. This only applies to the bond pads themselves, to concentrate the ferromagneticmetalized particles within the ACE more towards the connection points. This creates a higher density of columns within each pad.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk3MTAzNzcyMzM0LUZpZyA4LnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 488px;" class="fr-fic fr-dib"><figcaption data-pm-slice='1 1 ["figureImage",null]' id="isPasted">Figure 8. Left: No nickel interlayer and ACE; Right: ACE after cure with Nickel interlayer layer in pads</figcaption><h3 data-pm-slice="1 1 []" id="isPasted">Conclusion</h3>Besides the addition of the nickel layer to the functional die, key parameter targets were updated for the project’s next phase. In the short-term alignment, fiducials on the quartz plates were updated to improve bonding in X, Y, and theta; and the size of test probe pads were increased to improve accuracy and reduce testing time.The development efforts for all three examples are still underway. The conclusions thus far are:<ul><li>Successful demonstrations of Heterogenous Packaging using z-axis magnetically aligned epoxy for structural &amp; electrical bonding.</li><li>Similar established process techniques and test methodologies are usable across applications, although each has unique requirements.</li><li>The Ultra Fine particles ACE formulation has the best performance for finer pitches and more challenging alignments.</li><li>Uniform bond lines between device pads are critical for optimum electrical performance.</li><li>Excellent performance results were obtained, even with manual assembly techniques. Performance will improve with automation.</li></ul>In concept this z-axis magnetically aligned conductive epoxy approach could integrate multiple silicon wafers on top of each other, creating the possibility for an exceptionally dense integrated System-In-a-Package (SIP). Processing temperatures can be as low as 80°C, opening room for alternate substrates and biocompatible assemblies. This anisotropic epoxy is not limited to specific device attachment; it can be used to bond multiple component sizes and styles across an entire substrate.<hr>Join us in Berlin and/or Boston and lets us RESHAPE the Future of Electronics, making it Additive, Sustainable, Hybrid, Wearable, and 3D - techblick.com<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1699454093608-B-and-B-2024%28small-LinkedIn+for-email%29.jpg" style="width: 709px;" class="fr-fic fr-dib">

Fine-Pitch Direct Die Attach Without Thermal Compression, Alignment or Underfill

Fine-pitch dense die assembly process with only a single adhesive application without pressure, without underfill, without fine patterning, without complex alignment vs solder ball-to-solder pad, etc? Learn here how magnetically aligned Anisotropic Conductive Epoxy (ACE) enable this

<a href="https://www.linkedin.com/in/carolyn-ellinger/" target="_blank" rel="noopener noreferrer">Carolyn Ellinger,</a> <a href="https://www.linkedin.com/in/chris-oconnor-01bb494/" target="_blank" rel="noopener noreferrer">Chris O’Connor</a>, <a href="https://www.linkedin.com/in/christopher-liston-49614326/" target="_blank" rel="noopener noreferrer">Chris Liston</a>, Emily Rej,&nbsp;<a href="https://www.linkedin.com/in/thomas-leblanc-0009a246/" target="_blank" rel="noopener noreferrer">Tom LeBlanc</a> - Eastman Kodak Company&nbsp;Built on expertise in coating, printing, and image quality, Kodak's printed electronics products and contract manufacturing services offer customers modern functionality rooted in decades of manufacturing excellence.Flexible heaters were first developed in the late 1800s, around the same time as Kodak was starting to manufacture film products &nbsp; While these first flexible heaters were textile-based, they operate on the same resistive heating principles as today’s flexible film heaters. &nbsp;With new technologies come new challenges and limitations, and “hidden” heaters are being deployed to improve the functionality of a broad range of electronic systems. &nbsp; Temperature-limited electronic devices, such as LCDs, require heating to be able to operate in cold environments.&nbsp;Outdoor sensors require that ice and snow be removed from their front surface to ensure their operation. Each of these applications (many many more) requires transparency and heating.&nbsp;However, while each application nominally requires “heat” and “transparency” – the requirements and form-factors of these transparent heaters vary across applications, and from device to device.Kodak’s manufacturing process for fabricating highly transparent patterned heating films delivers designs optimized for individual customers, various integration paths, and a myriad of end-devices.&nbsp;The copper micro-wire designs are manufactured with 2-μm imaging resolution, enabling ultimate freedom in macroscale and microscale optimization. &nbsp;The fully additive, roll-to-roll printed electronics manufacturing process produces copper micro-wires by printing a catalytic ink in the desired pattern, and then electrolessly plating copper to the specified height allowing for independent control of transparency and sheet resistance.As described in this white paper, Kodak works with customers to determine the optimum heater design. &nbsp;Figure 1a illustrates a simple approach in designing for a desired power density at a given system voltage. &nbsp;Figure 1b illustrates just a few of the many possible designs for uniform transparent heating.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk1NDk5MzQ2MTU2LVNjcmVlbnNob3QgMjAyMy0wOS0yMyAwNzU2NDgucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 628px;" class="fr-fic fr-dib">Figure 1a. &nbsp;Example of heater designs for system optimization. &nbsp;Each heater has the same heated area, same transparency, but have been tuned to a different resistance (R) to achieve the required power density (PD) and the supply voltage of a given application.&nbsp;<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk1NDk5Mzc1MzM5LVNjcmVlbnNob3QgMjAyMy0wOS0yMyAwNzU3MTYucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 663px;" class="fr-fic fr-dib">Figure 1b. &nbsp;Example heater patterns.&nbsp;<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1699454536681-B-and-B-2024%28e-mail%29.jpg" style="width: 738px;" class="fr-fic fr-dib">Join us in Berlin and/or Boston and lets us RESHAPE the Future of Electronics, making it Additive, Sustainable, Hybrid, Wearable, and 3D - techblick.comHow do resistive heaters work?Resistive heaters function by Joule heating, also known as Ohmic heating, where the flow of electric current through a conductor produces heat. &nbsp;All conductive materials exhibit this resistive heating phenomenon, with the heating response varying based on the specific properties of each material. Resistance is defined as the resistance to the flow of current at a given voltage bias, or R = V/I.&nbsp;Heater power is a function of the amount of current that is driven through an element of a given resistance: &nbsp;P = I2R = V2/R.Therefore, a heater with a higher resistance will require less current to generate the same power. Conversely, a conductive trace with low resistance will have lesser heating when current is applied than a higher resistance trace. In typical operation, heaters are driven by a constant voltage power supply, and a heater with a lower resistance will consume more power and heat to a higher temperature. &nbsp;The resistance of any heater is a combination of the pattern of the resistive element and the electrical properties of the material used. &nbsp;The resistance of conductors of a given thickness can be expressed as sheet resistance (Rs) in Ohm/square, so the end-to-end (terminal) resistance of any conductive pattern is Rs*L/W where L/W is the number of squares. &nbsp;Consequently, at a given operating voltage, the power per unit area or power density (PD) is proportional to 1/R, and 1/Rs for square heater element as shown in Figure 2.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk1NDk5NTQwNzA2LVNjcmVlbnNob3QgMjAyMy0wOS0yMyAwNzQ4MTUucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 652px;" class="fr-fic fr-dib">Figure 2. &nbsp;Power density of a square heater at various voltage levels as a function of sheet resistance.What Sets the Kodak Technology Apart?Kodak’s cleanroom manufacturing leverages Kodak’s long history of innovation in material science, image science, printing, deposition, and roll-to-roll manufacturing to produce patterned micro-wire films with the unprecedented combination of high transparency, neutral color, low reflectance, and low sheet resistance. &nbsp;Cleanroom manufacturing minimizes electrical yield losses and ensures that parts will be free of transparency-reducing particulate going into final integration. &nbsp;The fully additive, roll-to-roll process features ~2 µm imaging resolution to produce fine copper micro-wires as narrow as 5 µm in width, by first printing a patented catalytic ink and then electrolessly plating copper to the desired height. The process enables the ability to independently tune sheet resistance and transparency, the ability to manufacture films with highly conductive traces leading to more resistive heating elements, and the ability to form multiple devices or electrical elements on a single substrate in a single roll to roll manufacturing flow – on one or both sides of the substrate.&nbsp;The design tools of the Kodak process enable functional heater designs without sacrificing transparency through a combination of mesh design (line dimensions, gaps, curves and angles), copper thickness, and the resistive path of the heater. &nbsp;Not only can the Kodak process support freeform design--only limited by imagination--other supporting elements such as traces, bond pads and even non-conductive or graphic can be additively included. &nbsp;Transparent mesh designs are readily obtainable with visible light transmission (VLT)&gt;85% with Rs from 1 to 5 Ohm/square, as illustrated in Figure 3.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk1NDk5NjY1NDk2LVNjcmVlbnNob3QgMjAyMy0wOS0yMyAwNzQwNTYucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 634px;" class="fr-fic fr-dib">Figure 3. Kodak copper micro-wire mesh performance for a variety of mesh patterns represented the ratio of pitch to linewidth (LW) and copper thicknesses.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1699454600236-B-and-B-2024%28blog%29.jpg" style="width: 766px;" class="fr-fic fr-dib">Join us in Berlin and/or Boston and lets us RESHAPE the Future of Electronics, making it Additive, Sustainable, Hybrid, Wearable, and 3D - techblick.comThe design freedom that comes from patterning via printing enables not only the pattern selection optimized for transparency, but also optimization of the overall design of the heater for a given system. &nbsp;For example, if the application has a square area that requires uniform heating a possible heater design would be a single square patch of resistive heater, but in this case the power density achievable would be limited by both the sheet resistance of the heater and the operating voltage available in the system. &nbsp;Typically, an application will have specified power, temperature and voltage requirements and a heater must be designed to operate at those conditions. &nbsp;Figure 4 illustrates how heaters may be designed using the mesh designs of Figure 3, with a reference shown at 100 W/m2 and the design choices depending on the supply voltage. For example, if a 3V power supply is chosen then a three-leg heater design is preferred, but if a 12V power supply is chosen, then a 3-leg heater would not be suitable and a 7-leg heater is preferred.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNjk1NTAwNjkyMTM2LVNjcmVlbnNob3QgMjAyMy0wOS0yMyAwNzQ5MTEucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 742px;" class="fr-fic fr-dib">Figure 4. Illustration of heater designs to obtain a desired power density versus supply voltage.Ready-to-Integrate Transparent HeatersKodak is seeking strategic integration partners for transparent conductive heaters. &nbsp;Products and devices from this manufacturing line include all benefits discussed above, and ready-to-integrate films can be supplied for evaluation.Contact InformationFor more information on Kodak’s micro-wire technology and enabling manufacturing process, please contact: <a target="_blank" rel="noopener noreferrer" data-fr-linked="true" href="mailto:sales.printedelectronics@kodak.com">sales.printedelectronics@kodak.com</a>. Join us in Berlin and/or Boston and lets us RESHAPE the Future of Electronics, making it Additive, Sustainable, Hybrid, Wearable, and 3D - techblick.com<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1699454617822-B-and-B-2024%28small-LinkedIn+for-email%29.jpg" style="width: 766px;" class="fr-fic fr-dib">

Kodak has a long history of manufacturing quality film products – starting with silver halide imaging films for consumers. Learn how Kodak is continuing that history, manufacturing a variety of industrial film products in many industries – from automotive to batteries to healthcare.

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