Until now, monitoring your heart often required uncomfortable chest straps or other awkward tests. Researchers at Rice University are changing the process with their development of smart clothing with conductive carbon nanotube threads woven into regular athletic apparel. The fibers are comfortable and flexible, and the zigzag stitching pattern allows the fabric to stretch without breaking the fibers.  The carbon nanotube threads are as conductive as metal wires, and the clothing is machine washable. 

The original nanotube filaments were too thin for a sewing machine (about 22 microns wide) so the researchers worked with a rope maker to create bundle the threads, essentially three bundles of seven filaments each, into a thickness roughly the size of a traditional thread. The research team is working with the Texas Heart Institute to determine how to maximize contact with the skin. 

The fibers provide steady electrical contact with the wearer’s skin and served as electrodes allowing transmission to Bluetooth transmitters to a Holter monitor. The shirt outperformed traditional EKGs conducted using commercial medical electrode monitors and was better at taking live measurements than the standard chest-strap monitors.  

Future applications of this technology could include embedding antennas or LEDs into fabrics. Minor modifications could eventually allow clothing to monitor vital signs, exertion, or respiratory rate. The technology could even be used in military uniforms. “We demonstrated with a collaborator a few years ago that carbon nanotube fibers are better at dissipating energy on a per-weight basis than Kevlar, and that was without some of the gains that we’ve had since in tensile strength,” Rice graduate student Lauren Taylor, lead author of the study, explained.  

“We see that, after two decades of development in labs worldwide, this material works in more and more applications,” said Matteo Pasquali, Rice University’s Brown School of Engineering lab chemical and biomolecular engineer, said. “Because of the combination of conductivity, good contact with the skin, biocompatibility and softness, carbon nanotube threads are a natural component for wearables.”