Researchers at the University of California San Diego have introduced an innovative electronic finger wrap that monitors vital biomarkers like glucose, vitamins, and drugs using sweat from the fingertips.
“This is automatic health monitoring at your fingertips,” said Shichao Ding, one of the study’s co-first authors. Remarkably, the device works even when the user is resting or sleeping, harvesting energy from the sweat to track critical chemical levels without requiring physical activity.
The sweat-powered device could make personalized health monitoring as simple as wearing a Band-Aid. This development builds upon recent research in fingertip sweat analysis. Earlier this year, the University of Surrey used fingertip sweat to detect antibiotics in the bloodstream with nearly the same accuracy as blood tests.
Fingertips are surprisingly efficient sweat producers, containing over a thousand sweat glands each. This makes them an ideal source of energy for the sensor, which fits comfortably around the finger and continuously draws power from this abundant resource. The device is constructed using printed electronic components embedded in a flexible, stretchable polymer, allowing it to conform to the finger while withstanding movement and wear.
“It is based on a remarkable integration of energy harvesting and storage components, with multiple biosensors in a fluidic microchannel, along with the corresponding electronic controller, all at the fingertip,” said Joseph Wang, whose research team at UC San Diego spearheaded the project.
At the heart of the device are biofuel cells that convert chemicals found in sweat into electricity. This energy is stored in two stretchable silver chloride-zinc batteries that power four sensors. Each sensor is dedicated to detecting a specific biomarker: glucose, vitamin C, lactate, and levodopa, a drug used in Parkinson’s disease treatment.
Sweat flows through tiny paper-based microfluidic channels, allowing the device to analyze biomarker levels while simultaneously powering itself. A small chip processes this data and wirelessly transmits it to a custom app on a smartphone or laptop using Bluetooth technology.
In initial tests, the device was used throughout the day to monitor glucose levels during meals, lactate levels during desk work and exercise, vitamin C after consuming orange juice, and levodopa after eating fava beans, which are a natural source of the compound.
The device offers the potential for customizable health tracking, allowing users to monitor biomarkers based on individual health requirements. The researchers are working toward developing a closed-loop system that not only monitors biomarkers but also administers treatments based on the collected data.
“Autonomous power, sensing, and treatment all in one device—that’s the ultimate goal,” Ding emphasized. For example, this device could continuously monitor glucose levels in diabetics, automatically deliver insulin, and then track the treatment’s effectiveness through real-time biomarker analysis.