© 2022 Cincinnati Public Radio
Connecting You to a World of Ideas
Play Live Radio
Next Up:
Available On Air Stations

This wearable health sensor could be a game-changer because it's chip-less

man holds a square gold sensor
Andrew Higley
Yeongin Kim, UC assistant professor of electrical engineering, created a novel wearable and wireless sensor.

The world of health sensors is big business. A new report says it will grow to $142 billion by 2030 spurred by an increasing geriatric population, more interest in fitness and a prevalence of chronic disease.

Not all medical sensors are equal. A University of Cincinnati assistant professor in the College of Engineering and Applied Science has developed one that is flexible, stretchy, wireless and doesn’t have any computer chips.

Yeongin Kim describes his sensor as a second skin, with more applications than the Fitbit and the Apple Watch, he says

“You are hardly able to feel it,” he says.

This tiny device sticks to your skin similar to a Band-Aid. He’s already tested its wearability and breathability. An article in the journal Science details Kim’s most recent research where it monitored pulse and UV light.

The novel design involves a thin gold-film antenna which is connected to a 200-nanometer (think just 10 times thicker than a human hair) thick piezoelectric film. The reaction generates an electrical charge from mechanical stress.

“We made a very strange material,” says Kim. “I will call it strange material because it has not been commonly used before.”

Piezoelectric is the electric polarization in a substance resulting from the application of mechanical stress. Sounds complicated, but it's really just using crystals to convert mechanical energy into electricity, or vice versa.

The website Explain That Stuff says, “if you've got a quartz watch, piezoelectricity is what helps it keep regular time. If you've been writing a letter or an essay on your computer with the help of voice recognition software, the microphone you spoke into probably used piezoelectricity to turn the sound energy in your voice into electrical signals your computer can interpret.”

What can this sensor sense?

Kim says all kinds of biomarkers could be monitored, including mechanical strain, pathogen detection, and glucose and hormone sensing. Hormone monitoring could tell a lot about mental health.

“People, when they get stressed out, they release the stress hormone called cortisol and there’s a lot of interest in long-term monitoring of this kind of stress hormone because people these days are suffering from depression and panic disorders,” says Kim.

Real-time information doesn't come cheap. Until there's more demand and more vendors, the materials Kim’s sensor uses will remain more expensive than ones using computer chips.

Kim continues to make his biosensor better. Eventually his device and others could be implanted inside the body.

diagram of sensor.jpg
Jun Min Suh
Massachusetts Institute of Technology
The surface acoustic wave sensor and gold dumbell-pattern antenna are affixed to a piezoelectric film and a microns-thick adhesive material that allows the wireless sensor to be worn comfortably for long periods.

With more than 30 years of journalism experience in the Greater Cincinnati market, Ann Thompson brings a wealth of knowledge and expertise to her reporting. She has reported for WKRC, WCKY, WHIO-TV, Metro Networks and CBS/ABC Radio. Her work has been recognized by the Associated Press and the Society of Professional Journalists. In 2019 and 2011 A-P named her “Best Reporter” for large market radio in Ohio. She has won awards from the Association of Women in Communications and the Alliance for Women in Media. Ann reports regularly on science and technology in Focus on Technology.