According to foreign media reports, Rice University researchers recently demonstrated a clothing with carbon nanotubes that can continuously monitor the wearer's heart. There's no need to wear an uncomfortable smartwatch or chest strap to monitor your heart if your comfortable clothing does a better job. That's the idea behind "smart clothing" developed by a Rice University lab that uses its conductive nanowires to weave functionality into regular clothing.
Matteo Pasquali, a chemical and biomolecular engineer at the school's Brown School of Engineering, reports in Nano Letters, a journal of the American Chemical Society, that it sewn nanotube fibers into sportswear to monitor heart rate and perform continuous electrocardiographic monitoring of the wearer. .
According to the researchers, the fibers are as conductive as metal wires, but are washable, comfortable, and much less likely to break when the body is in motion. Overall, their enhanced garments were better at collecting data than standard chest-strap monitors that took field measurements in the experiments. When matched with commercial medical electrode monitors, the carbon nanotube garments performed slightly better on ECGs.
"The garment had to fit snugly against the chest," said Rice graduate student Lauren Taylor, lead author of the study. "In future research, we will focus on using denser blocks of carbon nanowires so that there is more surface area to contact the skin."
The researchers point out that the nanotube fibers are soft and elastic, and clothes incorporating them can be machine washed. These fibers can be machine sewn onto the fabric like standard thread. The zigzag stitching pattern allows the fabrics to stretch without breaking them.
The fibers not only provide a stable electrical contact with the wearer's skin, Taylor said, but also act as electrodes to connect electronic devices such as Bluetooth transmitters, relay data to smartphones, or connect to Holter monitors that can fit in the user's pocket. device.
Pasquali's lab introduced carbon nanotube fibers in 2013. Since then, fibers containing tens of billions of nanotubes each have been studied to repair bridges in damaged hearts, as electrical interfaces to the brain, for cochlear implants, as flexible antennas, and for automotive and aerospace applications. Their development is also part of the Rice-based Carbon Center, a multi-university research initiative led by Rice and launched in 2019.
The original nanotube filaments were about 22 microns wide, too thin for a sewing machine to handle. A rope maker was used to create the sewable thread, basically three bundles of seven filaments each, woven to roughly the same size as regular thread, Taylor said.
"We worked with a guy who sold a little machine designed to make ropes for model boats," says Taylor, who initially tried to weave the thread by hand with limited success. "He was able to make us a mid-scale device that could do that."
The zig-zag pattern can be adjusted to account for how much stretch a sportswear or other fabric may be, she said. Taylor said the team is working with Dr. Mehdi Razavi and his colleagues at the Texas Heart Institute to figure out how to maximize skin contact.
The fibers woven into the fabric could also be used to embed antennas or LEDs, the researchers said. Slight modifications to the fiber geometry and associated electronics could eventually allow clothing to monitor vital signs, effort or breathing rate.
Other potential uses could include human-machine interfaces in cars or soft robots, or as antennas, health monitors and bulletproof protection for military uniforms, Taylor noted. "We demonstrated with a collaborator a few years ago that carbon nanotube fibers dissipate energy better per unit weight than Kevlar fibers, and that's without some of our later progress in tensile strength," she said. "
"We're seeing this material play a role in more and more applications after 20 years of development in laboratories around the world," Pasquali said. "Carbon nanotubes are a natural building block for wearable devices due to their combination of electrical conductivity, good skin contact, biocompatibility and softness."
The wearables market, while relatively small, could be an entry point for a new generation of sustainable materials that can be extracted from hydrocarbons through direct splitting, a process that also produces clean hydrogen, he said. Developing this material is a focus of the Carbon Center.
"We are in the same situation as solar cells were decades ago," Pasquali said. "We need application leaders that can power scale-up of production and improve efficiency."
