Every day, millions of kidney patients around the world undergo blood tests or provide urine samples. Startup DXcrete aims to end that tedious routine with a smart patch that continuously analyzes sweat and extracts a wealth of health information from it. Founder and TU/e researcher Emma Moonen: "With our technology, patients no longer have to visit the hospital for every test and we can monitor them continuously. This way we can identify any deterioration much sooner and hopefully drastic interventions will be less often necessary."
In her office, Emma Moonen (28) slides something across the table that looks like a semi-transparent patch with a USB connector attached. "This is the BEA," she says, holding the tiny device up to the light. "A new way to collect and analyze sweat, even when you hardly perspire."
Moonen earned her PhD with honors in March 2024 at TU/e's Department of Mechanical Engineering and co-founded DXcrete together with former Philips engineer Timon Grob. Their mission: to extract vital health information from patients' sweat in a painless, comfortable, and continuous way.
"Sweat is 99 percent water, but that remaining one percent contains a treasure trove of information about one's health," Moonen says enthusiastically. "Until now, we've relied on urine or blood samples for that data. It's time-consuming, uncomfortable, and only gives a snapshot. Our method is pain-free, continuous, and has a high degree of reliability."
Moving very tiny droplets with electric fields
"Our device can collect and move nanoliter-sized droplets of sweat, about a billionth of a liter, toward integrated sensors," she says. "For comparison: a single drop of water contains about 50,000 nanoliters, depending on its size." The underlying technology is called electrowetting, a method that uses electric fields to move droplets of liquid. In this case they get moved toward a tiny reservoir where measurements are taken.
It sounds futuristic, but electrowetting itself isn't new. "The technology is already being used in certain digital billboards, where water droplets move in oil, like tiny pools of ink that rearrange themselves under the influence of an electrical voltage."
E-readers use a related technique: electrically charged black and white pigment particles move in microcapsules, which together form a page. "We've applied the same principle to the human body, specifically to collect and transfer sweat."
From research to startup
The idea of using electrodes to collect sweat originated during Moonen's PhD research within the Microsystems group of professor Jaap den Toonder , in collaboration with Philips, Catharina Hospital Eindhoven, and several SME partners. "We wanted to develop a way to monitor patients-at-rest through sweat, but the problem is that people hardly perspire when they're resting", she says. "That's why we needed a method to 'transport' droplets to a tiny reservoir for collection."
IT'S ABOUT IMPROVING THE QUALITY OF PATIENTS' LIFE, REDUCE PRESSURE ON THE HEALTHCARE SYSTEM AND ULTIMATELY SAVING LIVES.
Emma Moonen, TU/e researcher and co-founder of DXcrete
A breakthrough came when one of her PhD committee members linked the concept of electrowetting to the challenge of sweat transport. With a 185,000 euro grant from NWO's Faculty of Impact program, Moonen and her co-founder launched DXcrete, with TU/e taking a stake through TU/e Participations .
Focus on kidney patients
DXcrete's first concrete application focuses on measuring creatinine, a waste product filtered from the blood by the kidneys. "The amount of creatinine in your blood tells us a lot about kidney function. Too much of it can indicate kidney failure," Moonen explains.
According to the Dutch Kidney Foundation , one in ten people in the Netherlands suffers from chronic kidney disease. Dialysis (the artificial cleansing of blood when the kidneys are unable to do so sufficiently) costs between 80,000 and 120,000 euros per patient per year. "With our technology, patients can be monitored continuously without having to travel to the hospital for every test. That allows us to detect problems much earlier, hopefully reducing the need for major interventions."
Even the journey to the hospital can affect test results. "If you cycle to your appointment, your creatinine levels might already rise slightly due to physical activity," says Moonen. "With our method, such snapshots are avoided, while changes in biomarkers are picked up more quickly."
Because the BEA sits on the skin like a sensor patch, patients barely notice it. And while electricity and moisture may seem a risky combination, Moonen reassures: "The voltage is extremely low. Even if a short circuit occurres, which we've safeguarded against, there's no way to receive an electric shock. The current is simply too weak." The goal is for the BEA to be worn for several days or even weeks before replacement.
Although the device will not completely replace blood draws, it can significantly reduce their frequency. "We can't fully replace blood testing yet," Moonen admits, "but we do hope to move the clinic toward a much more 'sweat-minded' approach. "Our solution extracts information from sweat much more frequently than blood samples and enables continuous patient monitoring. Blood or urine samples are still needed to detect the disease, but afterward, we can use the BEA to track its progression without having to take repeated samples.
New sensor, new application
The current prototype works via Bluetooth and functions as a 'sweat-on-a-chip.' But Moonen and her team have broader ambitions. "We want to integrate other sensors that can detect additional biomarkers in sweat. For example, a Belgian partner has developed a lactate sensor. We want to integrate it, connecting a different sensor to the chip. This method would allow for the analysis of different substances with each sensor swap."
The coming months DXcrete will focus on optimizing sweat collection at rest and securing additional funding. "That will allow us to expand our team and start preclinical studies," Moonen says. The goal is to begin clinical testing next year and pursue a CE certification (european health and safety marking), allowing the BEA to be marketed as a medical device.
As she carefully places the BEA back in its case, Moonen reflects: "What we're doing goes beyond technological innovation. It's about improving patients' quality of life, reducing pressure on the healthcare system, and ultimately saving lives through earlier detection of kidney function decline."
Postscript: In related PhD research, Xiaoyu Yin has developed mathematical models that translate blood values into equivalent sweat data, helping determine how substances found in sweat correspond to their concentrations in the blood.
