First Fully Integrated Smart Ring Monitors Glucose, Ketone, and Other Biomarkers in Sweat Simultaneously
Key Insights
UC San Diego engineers developed the first fully integrated smart ring that continuously monitors up to four chemical biomarkers from finger sweat without requiring exercise.
The ring tracks glucose, ketones, vitamin C, uric acid, lactate, and alcohol, with glucose readings closely matching commercial CGMs and ketone (search) readings matching blood meters.
Sweat is collected passively via an osmotic hydrogel technique, and the ring operates for up to 12 hours on a flexible rechargeable battery.
Engineers at the University of California San Diego have created what they describe as the first fully integrated smart ring capable of simultaneously and continuously monitoring multiple chemical biomarkers from finger sweat. The device, reported in Nature Communications, represents a significant advance over commercial wearable rings that currently provide only biophysical information such as heart rate or step count.
"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 study first author Tamoghna Saha, a postdoctoral researcher in the lab of Joseph Wang, professor in the Aiiso Yufeng Li Family Department of Chemical and Nano Engineering at the UC San Diego Jacobs School of Engineering.
The complete array of biomarkers the smart ring can monitor in sweat includes glucose, ketones, vitamin C, uric acid, lactate, and alcohol. The device can track up to four of these biomarkers simultaneously.
Passive Sweat Collection Without Exertion
A key innovation of the device is that it does not require exercise or physical exertion to generate sweat. Instead, sweat is passively drawn up through the surface of the skin via osmosis using a technique pioneered by Saha. The ring employs an osmotic hydrogel—a soft polymer that creates a pressure gradient to pull fluid from the skin painlessly, functioning similarly to how water travels from soil to leaves in plants.
The collected sweat is then analyzed by an electrochemical sensor array embedded within the ring. Through repeated measurements, subject-specific calibration factors are established to convert current responses into concentration values, enabling more personalized insight into biomarker trends.
Clinical Validation Against Commercial Devices
In trials conducted with both healthy volunteers and people with type 1 diabetes (search), the biomarker smart ring's glucose readings closely tracked those from commercial continuous glucose monitors (CGMs). Similarly, the ketone (search) readings closely matched ketone readings obtained from commercial blood meters.
"A ring capturing dynamic molecular information in real time would be extremely useful for making informed decisions regarding health, diet and lifestyle," said Joseph Wang. "For example, the ring's ability to track both glucose and ketone (search) continuously and simultaneously would greatly benefit optimal insulin dosing for the management of diabetes."
Fully Integrated Engineering
The smart ring is a fully integrated prototype housing all necessary biomarker sensing technology, low-power electronics, and a flexible battery within a compact form factor. The electronic board dimensions are smaller than a US quarter coin, and the outer shell is constructed from a 3D-printed polymer.
Power is supplied by a flexible zinc-silver oxide rechargeable battery that supports up to 12 hours of operation between charges. Biomarker information is transmitted wirelessly to a smartphone app for user access and analysis.
"Such integration onto the small footprint of a ring form factor is amazing," Wang said.
Tracking multiple biomarkers simultaneously has the potential to broaden the real-time health picture across numerous scenarios, including diabetes management and nutrition tracking. The study's co-first authors are Tamoghna Saha, Shichao Ding, and Siyu Qin, all at UC San Diego. The work was supported by the UC San Diego Center of Wearable Sensors and the National Science Foundation through the UC San Diego Materials Research Science and Engineering Center.