From fingertip to insight: tracking health with sweat-powered sensors

In our latest Lexicon episode , we sit down with Shichao Ding , a postdoctoral researcher at UC San Diego, to discuss his team’s work on an innovative sweat-powered electronic finger wrap that can track a variety of health biomarkers like glucose, vitamin C, lactate, and drugs.

If, and indeed when, the device ever leaves the lab, it promises to make h ealth monitoring simpler , more continuous, and less invasive than ever before. Read on to find out how.

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Real-time health tracking at your fingertips

“We think we can do some kind of non-invasive, continuous, and easy method for directly monitoring biomarkers,” explained Shichao Ding to IE.

Traditionally, tracking health markers like glucose levels involves drawing blood. This is not painful but can be very inconvenient for patients, particularly those with chronic conditions like diabetes. However, this new seat-powered fingertip sensor seeks to change that by relying on fingertip sweat instead of blood.

As Ding explained, “We noticed lots of sweat glands on the fingertips that can generate a lot of sweat for you to analyze… You don’t need to have the blood draws.”

This means that the device allows for bona fide continuous health monitoring even when traditional blood tests are impractical, such as when a person sleeps or rests.

Food for thought

What is really cool about this new device is its ability to generate its power using sweat using special biofuel cells in its circuitry. These biofuel cells can extract energy from compounds like lactate and oxidants found in sweat to generate electricity.

“Our device collects energy passively from sweat,” Ding explains. “You can be at rest, asleep, or working, and the device will continuously generate power,” Ding explained.  “Even in sleep, as we call it, it’s a dream of power—harvesting energy from sweat without any physical movement,” he added.

The energy generated by the biofuel cells can be used directly to power the device or, if any excess is generated, stored in small, stretchable silver chloride-zinc batteries. These batteries provide an additional backup to allow the sensors to operate continuously throughout the day.

This setup also means the device can run under most conditions, even when exercising. Except, of course, for swimming.

Continuous, real-time monitoring is now possible

The electronic finger wrap is designed to track several key biomarkers in real-time. Currently, this includes biomarkers like glucose, vitamin C, lactate, and levodopa, a drug used to treat Parkinson’s disease.

These biomarkers were specifically chosen because of their relevance to health conditions like diabetes and their importance in overall metabolic processes. “These biomarkers are significant in the metabolic process and always change based on physical activities, meals, or sleep,” says Ding.

This tends to provide better qualitative results at the time but needs to be done at regular intervals to get an overall picture of the situation. Having a slightly lower-resolution continuous data flow gives patients and healthcare providers a more comprehensive view of the body’s metabolic activities.

“Our sensors match blood test results, showing that fingertip monitoring is promising for future continuous healthcare solutions,” Ding says.

The potential for continuous monitoring is especially valuable for conditions like diabetes. Instead of relying on painful blood samples, the device can track glucose levels non-invasively, making life easier for diabetics who need to closely monitor their blood sugar levels.

This opens up the possibility of more comfortable and convenient healthcare for millions worldwide. What’s more, it also opens up the possibility of autonomous medication supply should certain conditions be met (like the need for insulin in diabetics).

That would likely save many lives.

Flexible and customizable device

While the current version of the finger wrap tracks a handful of key biomarkers, Ding is quick to point out that the technology is highly adaptable. “The biomarkers we select are flexible. Based on our sensor technology, we can develop different configurations to match specific healthcare needs,” he explains.

This flexibility allows the device to be customized for different health conditions, meaning it could be adapted to track other biomarkers as needed.

For example, the device could eventually be tailored to monitor other disease-specific biomarkers besides glucose and vitamin C. He explained that they have already tested the device for levodopa, a drug used in Parkinson’s disease treatment, and foresee expanding to other areas of medicine.

“We want to make this a personalized health monitoring system, adaptable to various conditions and user needs,” Ding added.

The future of autonomous health monitoring?

One of the most exciting aspects of Ding’s research is the potential for autonomous health monitoring. In the future, devices like the electronic finger wrap could track biomarkers and administer treatments based on collected data.

“We envision integrating sensors with treatment systems,” Ding says, pointing to a future where wearables could detect rising glucose levels in diabetics and automatically deliver insulin.

This closed-loop system, which monitors health markers and responds with real-time interventions, could revolutionize managing chronic conditions. “The goal is to have a device that not only monitors but also acts—such as dosing insulin for diabetics—creating a seamless healthcare experience,” says Ding.

He notes that this vision extends beyond diabetes to other conditions, where continuous monitoring and immediate treatment could significantly improve patient outcomes.

More work needed

While this technology’s potential is vast, there are still challenges to overcome before it becomes widely available. One major hurdle is ensuring the long-term stability of biofuel cells and sensors.

“For mass production, we need to standardize sensor sensitivities and ensure stability across different users and conditions,” Ding explains. Another challenge is improving the efficiency of the biofuel cells to extend their lifespan.

Currently, they can work for one to two weeks before efficiency declines. Despite these challenges, Ding is optimistic about the future of this technology.

His team is improving sensor accuracy, extending the device’s lifespan, and exploring additional applications beyond health monitoring, including sports and fitness.

This new electronic finger wrap represents a significant advance in wearable health technology. His team has created a non-invasive, customizable, and continuous health monitoring solution by harnessing sweat’s power to monitor and power the device.

With the potential for future developments like autonomous treatment administration, this device could revolutionize healthcare, making it more accessible and personalized.

“We’re just beginning to see what’s possible with this wearable microgrid technology,” Ding told us.