What if the garments you don could contribute positively to your well-being?

Researchers from MIT have created an autonomous programmable processor in the form of a stretchy fiber, which is capable of tracking health conditions and physical movements, notifying the user about possible health threats in real-time. Apparel embedded with the fiber processor was reported to be comfortable and machine washable, with the fibers being almost undetectable to the wearer, according to the researchers.

In contrast to wearable monitoring devices that are typically situated at one point, such as the chest, wrist, or finger, textiles and clothing have the benefit of contacting extensive areas of the body near essential organs. Consequently, they offer a distinctive opportunity to assess and comprehend human biology and well-being.

The fiber processor encompasses a collection of micro-devices, such as sensors, a microcontroller, digital memory, Bluetooth modules, optical communication tools, and a power source, integrating all essential components of a computer into a single elastic fiber.

The researchers incorporated four fiber processors into a top and a pair of leggings, extending the fibers along each limb. During their tests, each programmatically independent fiber processor operated a machine-learning model trained to autonomously identify exercises performed by the user, achieving an average accuracy of approximately 70 percent.

Interestingly, once the researchers enabled the individual fiber processors to interact with one another, their combined accuracy surged to almost 95 percent.

“Our bodies emit vast amounts of data through the skin every moment in the form of heat, sound, biochemicals, electrical signals, and light, all of which convey details about our activities, feelings, and health. Sadly, most — if not all — of this data gets absorbed and subsequently lost within the fabrics we wear. Wouldn’t it be incredible if we could educate clothing to capture, analyze, store, and convey this critical information as valuable insights on health and activity?” remarks Yoel Fink, a professor of materials science and engineering at MIT, who is a primary investigator in the Research Laboratory of Electronics (RLE) and the Institute for Soldier Nanotechnologies (ISN), and a senior author of a study on this research, which was published today in Nature.

The application of the fiber processor to comprehend health conditions and assist in preventing injuries is set to undergo a notable practical examination soon. U.S. Army and Navy personnel will be partaking in a month-long winter exploration in the Arctic, covering 1,000 kilometers at average temperatures of -40 degrees Fahrenheit. Numerous base layer merino mesh shirts equipped with fiber processors will provide real-time insights into the health and activities of the individuals involved in this mission, termed Musk Ox II.

“In the foreseeable future, fiber processors will enable us to run applications and obtain critical health care and safety features from ordinary daily clothing. We are thrilled to witness glimpses of this future in the forthcoming Arctic mission through our collaborators in the U.S. Army, Navy, and DARPA. Assisting in ensuring the safety of our troops in the most extreme environments is an honor and privilege,” says Fink.

Joining him on the publication are co-lead authors Nikhil Gupta, a graduate student in materials science and engineering at MIT; Henry Cheung MEng ’23; and Syamantak Payra ’22, who is currently a graduate student at Stanford University; John Joannopoulos, the Francis Wright Professor of Physics at MIT and head of the Institute for Soldier Nanotechnologies; along with others at MIT, the Rhode Island School of Design, and Brown University.

Fiber emphasis

The fiber processor builds upon more than a decade of research conducted in the Fibers@MIT laboratory at the RLE and received significant support from ISN. In earlier studies, the researchers demonstrated techniques for integrating semiconductor devices, optical diodes, memory components, elastic electrical connectors, and sensors into fibers that could be fashioned into textiles and clothing.

“However, we encountered limitations regarding the complexity of devices we could integrate into the fiber due to our manufacturing methods. We needed to rethink the entire approach. Simultaneously, we aimed to make it elastic and flexible to align with the characteristics of conventional fabrics,” Gupta explains.

A challenge the researchers overcame was the geometric disparity between a cylindrical fiber and a flat device. Attaching wires to small conductive areas, known as pads, on the surface of each flat microdevice proved arduous and susceptible to failure because intricate microdevices possess numerous pads, complicating the reliable attachment of each wire.

In this innovative design, the researchers translate the 2D pad configuration of each microdevice to a 3D structure using a flexible circuit board dubbed an interposer, which is bent into a cylinder. They refer to this as the “maki” design. Next, they affix four distinct wires to the sides of the “maki” roll and connect all the components together.

“This enhancement was vital for us in terms of being able to embed higher functionality computing elements, like the microcontroller and Bluetooth sensor, into the fiber,” Gupta states.

This adaptable folding approach may be applied to various microelectronic devices, allowing for the incorporation of additional functionalities.

Moreover, the researchers manufactured the new fiber processor using a type of thermoplastic elastomer that is significantly more flexible than the thermoplastics previously utilized. This material enabled them to create a machine-washable, elastic fiber that can extend more than 60 percent without compromising integrity.

They produce the fiber processor utilizing a thermal draw technique that the Fibers@MIT group pioneered in the early 2000s. The method involves crafting a macroscopic version of the fiber processor, called a preform, containing each connected microdevice.

This preform is suspended in a furnace, melted, and drawn down to form a fiber, which also encloses embedded lithium-ion batteries, granting it self-powering capabilities.

“A former group member, Juliette Marion, discovered how to produce elastic conductors, so even when the fiber is stretched, the conductors remain intact. We can preserve functionality while stretching, which is essential for processes like knitting, as well as for clothing generally,” Gupta remarks.

Encouraging participation

Once the fiber processor is produced, the researchers apply a braiding method to cover the fiber with standard yarns such as polyester, merino wool, nylon, and even silk.

In addition to collecting data regarding the human body via sensors, each fiber processor incorporates LEDs and light sensors that enable multiple fibers within a single garment to communicate, forming a textile network capable of computation.

Each fiber processor also features a Bluetooth communication system to wirelessly transmit data to a device, like a smartphone, which can be accessed by the user.

The researchers utilized these communication networks to establish a textile system by sewing four fiber processors into a garment, one on each sleeve. Each fiber operated an independent neural network trained to recognize exercises like squats, planks, arm circles, and lunges.

“What we discovered is that the precision of a fiber processor in identifying human activity was only about 70 percent when situated on a single limb, either the arms or legs. However, when we enabled the fibers on all four limbs to ‘vote,’ they collectively attained almost 95 percent accuracy, underscoring the significance of positioning on various areas of the body and

“establishing a network among independent fiber computers that does not require cables and connections,” Fink states.

Looking ahead, the scientists aim to utilize the interposer method to integrate additional microdevices.

Insights from the Arctic

In February, a diverse team equipped with computational fabrics will embark on a journey lasting 30 days and spanning 1,000 kilometers in the Arctic. The fabrics will aid in ensuring the safety of the team and pave the way for upcoming physiological “digital twin” simulations.

“As a leader with over ten years of experience in Arctic operations, one of my primary concerns is ensuring my team’s protection against severe cold weather injuries — a significant hazard for operators in extreme cold,” states U.S. Army Major Hefner, the leader of Musk Ox II. “Traditional systems fail to give me a holistic view. We will be wearing the base layer computing fabrics continuously to help us gain a deeper understanding of how the body reacts to extreme cold, ultimately aiming to foresee and avert injuries.”

Karl Friedl, senior research scientist for performance physiology with the U.S. Army, remarked that the programmable fabric technology from MIT has the potential to be a “transformative influence in daily life.”

“Envision advanced fiber computers in fabrics and clothing that can detect and react to the environment as well as the physiological state of a person, enhancing comfort and performance while offering real-time health surveillance and shielding against external risks. Soldiers will be the initial adopters and recipients of this innovative technology, which will be integrated with AI systems employing predictive physiological models and mission-critical tools to boost survivability in challenging settings,” Friedl explains.

“The merging of traditional fibers and fabrics with computation and machine learning is just the beginning. We are delving into this thrilling future not only via research and field trials but also through an MIT Department of Materials Science and Engineering course titled ‘Computing Fabrics,’ instructed by Professor Anais Missakian from the Rhode Island School of Design,” Fink adds.

This research received partial funding from the U.S. Army Research Office Institute for Soldier Nanotechnology (ISN), the U.S. Defense Threat Reduction Agency, the U.S. National Science Foundation, the Fannie and John Hertz Foundation Fellowship, the Paul and Daisy Soros Foundation Fellowship for New Americans, the Stanford-Knight Hennessy Scholars Program, and the Astronaut Scholarship Foundation.