Engineers at the University of California San Diego announced on July 24 the creation of a smart ring that can simultaneously and continuously monitor up to four different chemical biomarkers from finger sweat. The full array of biomarkers that the device is capable of tracking includes glucose, ketones, vitamin C, uric acid, lactate, and alcohol.
In a paper published in Nature Communications, researchers in Joseph Wang's lab at the UC San Diego Jacobs School of Engineering reported results from what they described as the first fully integrated smart ring for daily biochemical monitoring. "Commercial rings only provide biophysical information, but they lack molecular information about biochemical markers that offers deeper insights about an individual's health status," said Tamoghna Saha, study first author and postdoctoral researcher in Wang's lab.
The technology uses a technique pioneered by Saha to passively draw sweat through osmosis without requiring exercise or exertion. This enables continuous biomarker detection without active participation by users. According to Wang, "A ring capturing dynamic molecular information in real time would be extremely useful for making informed decisions regarding health, diet and lifestyle." He added, "For example, the ring's ability to track both glucose and ketone continuously and simultaneously would greatly benefit optimal insulin dosing for the management of diabetes."
Trials with healthy volunteers and people with type‑1 diabetes showed that glucose readings from the biomarker smart ring closely matched those from commercial continuous glucose monitors (CGMs), while ketone readings were similar to those obtained using commercial blood meters.
The prototype incorporates all necessary biomarker sensing technology along with low-power electronics and a flexible battery. Biomarker data is transmitted wirelessly to a smartphone app. The device uses an osmotic hydrogel—a soft polymer—to painlessly pull fluid from skin into an electrochemical sensor array inside the ring. Subject-specific calibration factors are established through repeated measurements to convert current responses into concentration values for more personalized insights.
Powered by a flexible zinc-silver oxide rechargeable battery providing up to 12 hours between charges, the electronic board is smaller than a US quarter coin. The outer shell is made using 3D-printed polymer materials. "Such integration onto the small footprint of a ring form factor is amazing," Wang said.
