Smart Ring Continuously Monitors Glucose and Ketones from Passive Sweat

This gap limits continuous insight into biomarkers used to guide health management, including glucose and ketones relevant to diabetes care. Sweat-based sensing often depends on exercise, which is impractical for routine monitoring. To help address this challenge, engineers have developed a smart ring that continuously measures multiple biomarkers from passive finger sweat.

Engineers at the University of California San Diego introduced a fully integrated biomarker smart ring described as the first device of its kind for daily biochemical monitoring. The system, detailed in Nature Communications, can track up to four biomarkers simultaneously from a menu that includes glucose, ketones, vitamin C, uric acid, lactate and alcohol. The ring sends data wirelessly to a smartphone application for real-time visualization.

The ring passively draws minute amounts of sweat from the fingertip using an osmotic hydrogel that creates a pressure gradient at the skin surface. Collected fluid flows through an internal fluidic channel to an electrochemical sensor array that quantifies analytes. Repeated measurements generate subject-specific calibration factors that convert current responses into concentration values, enabling individualized trend analysis.

The prototype integrates low-power electronics and a flexible zinc–silver oxide rechargeable battery that supports up to 12 hours of operation per charge. The printed circuit board fits within a footprint smaller than a U.S. quarter, and the outer shell is produced with 3D‑printed polymer. The device architecture places the sensor array, sweat extraction component and fluidic channel on one half of the ring, with the battery and electronics on the other.

In trials with healthy volunteers and individuals with type 1 diabetes, the ring’s glucose measurements closely tracked values from commercial continuous glucose monitors, while ketone readings mirrored those from commercial blood meters. Monitoring multiple biomarkers at once is presented as a way to broaden real-time health assessment, with potential utility for diabetes management and nutrition tracking. The approach does not require exercise or other exertion to generate sweat, supporting use during everyday activities.

“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, a postdoctoral researcher in Wang’s lab.

“A ring capturing dynamic molecular information in real time would be extremely useful for making informed decisions regarding health, diet and lifestyle. 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,” said Joseph Wang, professor in the Aiiso Yufeng Li Family Department of Chemical and Nano Engineering at the UC San Diego Jacobs School of Engineering.

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