In a groundbreaking development, engineers at the University of California San Diego have introduced a finger-wrap device that uses sweat to power continuous health monitoring. This innovation, detailed in a study published on September 3 in Nature Electronics, combines wearable technology with biochemical analysis for seamless health tracking.
SWEAT AS AN ENERGY SOURCE: HARNESSING FINGERTIP PERSPIRATION
The new device, designed to fit snugly around the finger, draws its power from the fingertip’s sweat. Despite its small size, the fingertip is a prolific sweat producer, with over a thousand sweat glands capable of generating significantly more perspiration than other body areas, even at rest. This steady perspiration provides a reliable energy source for the device, enabling it to function even during inactivity or sleep.
HIGH-TECH DESIGN: FLEXIBLE AND DURABLE
Constructed from a thin, flexible polymer material, the finger wrap is engineered for durability and comfort. It features electronic components printed onto the polymer, which conform to the finger’s shape while enduring repeated movement. “It represents a remarkable integration of energy harvesting and storage components, with multiple biosensors in a fluidic microchannel, all positioned at the fingertip,” explains Joseph Wang, a professor in the Aiiso Yufeng Li Family Department of Chemical and Nano Engineering at UC San Diego.
BIOFUEL CELLS AND SENSORS: MONITORING VITAL BIOMARKERS
The core of the device’s functionality lies in its biofuel cells, which efficiently convert chemicals in sweat into electricity. This energy powers a set of four sensors, each designed to monitor specific biomarkers: glucose, vitamin C, lactate, and levodopa, a drug used for Parkinson’s disease. As sweat moves through microfluidic channels to the sensors, it provides real-time data on these biomarkers, with the information processed by a small chip and transmitted wirelessly via Bluetooth low energy to a custom smartphone or laptop application.
AUTOMATED HEALTH TRACKING: CONTINUOUS MONITORING AT YOUR FINGERTIPS
“This is automatic health monitoring at your fingertips,” says Shichao Ding, a co-first author of the study. The device enables users to monitor their health continuously, whether they are awake or asleep. Tests have shown its capability to track glucose during meals, lactate during both work and exercise, vitamin C after drinking orange juice, and levodopa following consumption of fava beans.
CUSTOMIZABLE AND FUTURE-READY: TAILORING TO INDIVIDUAL NEEDS
The device’s versatility extends to its customization, allowing it to detect various biomarkers based on individual health needs. Researchers are also developing a closed-loop system that would not only monitor but also administer treatments based on the collected data. For instance, in managing diabetes, the device could automatically adjust insulin delivery based on real-time glucose levels, then evaluate the treatment’s effectiveness through further monitoring.
THE ULTIMATE GOAL: AUTONOMOUS HEALTH MANAGEMENT
Ding highlights the ultimate ambition of this technology: “Autonomous power, sensing, and treatment all in one device.” As development progresses, this innovative finger-wrap could set a new standard for personal health management, combining continuous monitoring with automated treatment for a truly integrated approach to health care.
