In the past few years we’ve watched most of our electronics shrink and go wireless — that is, except our electrophysiological sensors. Doctors still track heart rate by gluing electrodes attached to wires to our skin, a technology that has changed little since its introduction in the 1970s. But research published today in Science presents a new kind of tiny sensor — and the beauty is that it’s only skin-deep.
A team led by John Rogers, who studies material sciences at the University of Illinois at Urbana-Champaign, redesigned an electrophysiological monitoring sensor, which can be used to measure heart rate, brain activity and muscle activity. They flattened all electronic parts to less than 7-nanometers thick, and attached the resulting 2-centimeter wide sensor to a stretchy, skin-like polyester sheet. The resulting device sticks to the skin without adhesive, and is nearly invisible, except for the gold electrical parts.
During a webcast for the press yesterday, Rogers peeled one of these sensors from his arm with tweezers, as shown in the video below. It looked like he was peeling off his own skin. “In some ways, it’s a little disgusting,” he told the online audience. “It looks like it’s been ripped from some part of the body.”
These sensors work just as well as the normal wire-bound electrodes. The researchers compared the electrical readings from the muscle and brain between their new sensor and standard electrodes, and found that the readings were nearly identical. Although they didn’t perform a direct comparison for heart rate, “the waveform was so obviously stereotypical that even the reviewers didn’t raise issue with that,” author Rui Ma, a postdoc in Rogers’ lab, wrote in an email. This high accuracy means that patients who need to monitor their vital signs at home could use these devices to do so without the discomfort of wires or the notice of others.
Rogers hopes the transition into a real commercial product won’t be a difficult one since most of the parts rely on off-the-shelf electronics, but he notes that there are still some kinks to work out, including a more robust wireless power supply. To bring their technology to market, the researchers have already partnered with a number of companies, including Reebok sportswear — a good sign for those who dream of tracking their heart rates through their workout clothes.
Image courtesy of John Rogers