A new skin-like computing patch developed at the University of Chicago Pritzker School of Molecular Engineering can analyze health data using artificial intelligence in an unprecedented way.

Unlike today’s wearable devices, it carries out its AI computations directly on the body, in mere milliseconds, without relying on a wireless connection, reports Sarah C.P. Williams in UChicago News.

While your current smartwatch may be able to track your heart rate or movements, it doesn’t analyze what it finds. The analysis happens elsewhere, after it shuttles data to an external server. In some situations—detecting ventricular fibrillation in the heart, for instance—that few-seconds lag to communicate with the server is too long.

The new device, designed and tested in collaboration with researchers at Argonne National Laboratory, was made possible by new manufacturing processes that allow organic electrochemical transistors to be printed onto flexible surfaces.

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“The future that we’re trying to realize is to make wearable and implantable devices smarter,” said Sihong Wang, an associate professor of molecular engineering at UChicago and co-senior author of the new study, published in Nature Electronics. “It’s helping people have a personal, instantaneous doctor integrated into their devices.”

Manufacturing stretchy transistors

For years, Wang’s lab has been working to create electronic components that can stretch and bend like human skin, with the goal of creating smart devices that adhere to human tissues. The group previously developed methods for fabricating stretchable transistor array and a stretchable OLED display.

In the new work, Wang and his colleagues set out to build a stretchable neuromorphic computing circuit—a large array of transistors that can run analyses of health data. Earlier work had demonstrated that the concept was theoretically possible with a small number of transistors but hadn’t scaled it up to a practical size.

The new device, designed and tested in collaboration with researchers at Argonne National Laboratory, was made possible by the development of manufacturing processes that allow organic electrochemical transistors to be printed onto flexible surfaces. Photo by John Zich

Saving lives with speedy computing

To test the new devices, Wang’s team used one of their new stretchable arrays to run a pre-trained algorithm designed to help treat ventricular fibrillation.

This dangerous electrical storm in the heart can be fatal and is most often treated with a one-size-fits-all defibrillator shock that delivers a massive jolt of electricity to the entire heart. Researchers have proposed a more precise treatment: mapping abnormal waves of electricity as they move through the heart and delivering small, precise pulses just ahead of them before they can continue.

However, the obstacle has been time. Wavefronts move through the heart so fast that the entire analysis must be completed within milliseconds—far too quickly for data to be transmitted to an external computer and back.

“This is a situation where it’s not feasible to have remote computing. It just takes too long,” said Wang. “But if you have a computing device that can do the analysis within the body, it could be possible.”
Using real cardiac mapping data from a donor human heart, the team showed the stretchable array could locate wavefront positions with 99.6% accuracy, even while the device was stretched to more than one and a half times its normal length.

In a separate demonstration, a neural network encoded in the array analyzed a combination of vital signs and personal health data—including cholesterol levels, blood sugar, maximum heart rate and ECG readings—to assess a patient’s risk of heart attack, achieving 83.5% accuracy.

Wang sees this computing array as one component of a fully integrated, body-compatible health platform. His lab is now working to pair the computing array with stretchable wireless communication components and improved sensors, moving toward a system that can sense, analyze and respond to health data as a fully integrated whole.

“Instead of sending data away to a remote server, we can begin making sense of it right where life is happening,” said Fangfang Xia, a computer scientist at Argonne National Laboratory and co-senior author of the study.