A new wearable device can send health data up to 15 miles, 2,400 times the distance of WiFi, without significant network infrastructure.
Wearable devices that use sensors to monitor biological signals can play an essential role in health care.
These devices provide valuable information that allows providers to predict, diagnose, and treat various conditions while improving access to care and reducing costs.
However, wearables currently require significant infrastructure—such as satellites or arrays of antennas that use cell signals—to transmit data, making many of those devices inaccessible to rural and under-resourced communities.
Researchers hope the new device will help make digital health access more equitable.
The COVID-19 pandemic and the strain it placed on the global healthcare system brought attention to the need for accurate, fast, and robust remote patient monitoring, says Philipp Gutruf, an assistant professor of biomedical engineering in the College of Engineering at the University of Arizona and lead author of the study in the Proceedings of the National Academy of Sciences.
Non-invasive wearable devices currently use the internet to connect clinicians to patient data for aggregation and investigation.
“These internet-based communication protocols are effective and well-developed, but they require cell coverage or internet connectivity and main-line power sources,” says Gutruf, a member of the BIO5 Institute. “These requirements often leave individuals in remote or resource-constrained environments underserved.”
In contrast, the Gutruf Lab developed system uses a low power wide area network, or LPWAN, that offers 2,400 times the distance of WiFi and 533 times that of Bluetooth. The new system uses LoRa, a patented type of LPWAN technology.
“The choice of LoRa helped address previous limitations associated with power and electromagnetic constraints,” says a biomedical engineering doctoral alumnus, Tucker Stuart.
Alongside implementing this protocol, the lab developed circuitry and an antenna, which, in usual LoRa-enabled devices, is a large box that seamlessly integrates into the soft wearable. These electromagnetic, electronic, and mechanical features enable it to send data to the receiver over a long distance.
To make the device almost imperceptible to the wearer, the lab also enables the recharge of its batteries over a distance of 2 meters (about 6.5 feet).
The soft electronics and the device’s ability to harvest power are the keys to the performance of this first-of-its-kind monitoring system, Gutruf says.
The Gutruf Lab calls the soft mesh wearable biosymbiotic, meaning it is custom 3D-printed to fit the user and is so unobtrusive it almost begins to feel like part of their body. The device, worn on the low forearm, stays in place even during exercise, ensuring high-quality data collection, Gutruf says.
The user always wears the device, and it charges without removal or effort.
“Our device allows for continuous operation over weeks due to its wireless power transfer feature for interaction-free recharging—all realized within a small package that even includes onboard computation of health metrics,” says coauthor Max Farley, an undergraduate student studying biomedical engineering.
The researchers plan to improve and extend communication distances by implementing LoRa wireless area network gateways that could serve hundreds of square miles and hundreds of device users using only a small number of connection points.
The wearable device and its communication system have the potential to aid remote monitoring in underserved rural communities, ensure high-fidelity recording in war zones, and monitor health in bustling cities, says Gutruf, whose long-term goal is to make the technology available to the communities with the most need.
“This effort is not just a scientific endeavor,” he says. “It’s a step toward making digital medicine more accessible, irrespective of geographical and resource constraints.”
