The wearable medical device market is growing at a little more than 27% annually and is forecast to reach a value of $174 billion by 2030, according to business intelligence firm Market Research Future. Given the potential of this technology to provide 24/7 health monitoring and diagnostics on an individual basis, its future growth may stretch well beyond even those numbers. The US Department of Energy’s Argonne National Laboratory in collaboration with the University of Chicago’s Pritzker School of Molecular Engineering (PME) are helping to bring that future to fruition by developing a skin-like device that is akin to having a “high-tech medical center at your instant beck and call.”
Future wearable electronics potentially could detect emerging health conditions even before obvious symptoms appear, suggests a news release from Argonne National Laboratory. The devices could also perform personalized analyses of the tracked health data while minimizing the need for its wireless transmission.
To collect and process such a vast amount of data at very low power consumption in a tiny space requires the use of a technology called neuromorphic computing, said the researchers. Based on artificial intelligence (AI), the technology mimics operation of the brain by training on past data sets and learning from experience. Its advantages include compatibility with stretchable material, lower energy consumption, and faster speed than other types of AI, said the news release.
The other major challenge the team faced was integrating the electronics into a skin-like stretchable material. Semiconductors used in current rigid electronic devices such as cell phones normally are a solid silicon chip. No matter how technologically advanced the wearable, it's well known that if the device is uncomfortable to wear, user adoption drops precipitously. In addition to being conductive, the material used for the semiconductor had to be highly flexible.
The research team’s skin-like neuromorphic chip consists of a thin film of a plastic semiconductor combined with stretchable gold nanowire electrodes. Three types of plastic were used in the construction, researcher Sihong Wang told PlasticsToday: "A type of conjugated polymer with semiconducting and ion-conducting properties, which have been engineered with stretchability through our research; an organo-hydro-gel as electrolyte; and a polydimethylsiloxane (PDMS) elastomer substrate.” Even when the device is stretched to twice its normal size, it functioned as planned without formation of any cracks.
To test the concept, the researchers built an AI device and trained it to distinguish healthy electrocardiogram (ECG) signals from four different signals indicating health problems. After training, the device was more than 95% effective at correctly identifying the ECG signals.
Exposure to an intense X-ray beam revealed how the molecules that make up the skin-like device material re-organize upon doubling in length. These results provided molecular-level information to better understand the material properties, said Argonne National Laboratory.