Wearable sensors designed for premature babies could make us all healthier

Wireless, biometric sensors give preemies more freedom and needed mom time

Babies born long before their due dates often spend several weeks in the neonatal intensive care unit, tethered to wires and medical gadgets. These devices monitor their vital signs, breathing, and even blood pressure—keys to keeping the babies alive—but are unwieldy and cumbersome, and often prevent their mothers and fathers from having that equally vital bonding time.

Because the equipment is crucial, doctors and parents have to make do, often forgoing some of that essential time. But a team of researchers at Northwestern University recently created small, sticker-like wireless biosensors that monitor necessary vital signs—all without large equipment and wiring. So far, they’ve tested the devices on a group of premature babies at the Robert H. Lurie Children’s Hospital of Chicago, who wore the new stickers alongside traditional wiring. Their results, published this week in the journal Science, show that these stickers might not just be useful in premature babies, but adults as well. And with easier access to vital signs via these stick-ons, doctors may be able to glean more key information than ever before.

Skin-to-skin contact between premature babies and their mothers is crucial, says Steve Xu, a dermatologist and the director of the Center for Bio-integrated Electronics at Northwestern University, and a co-author of the study. “It helps to stabilize their heart rates, improves their laboratory results and their breathing, and reduces stress,” Xu says, “but the number one barrier to skin-to-skin contact is hospital equipment.”

For some time, a team of materials scientists at Northwestern University, led by John Rogers, had been working on sensors that stick to the skin and monitor vital signs. They decided to try their technology out in a clinical setting in preemies first, because, as Rogers saw it, “we picked the NICU because it is hard. We purposively don’t go after low hanging fruit.” If they could get the device to function optimally on these premature infants—where there is also a great unmet need for the tech—then getting it to work in adults would be far easier. Further, babies this small usually have skin that is too sensitive and fragile for normal sticky sensors. Often, upon removing the stickers, their skin can get damaged or destroyed, leading to a painful healing process.

new wireless biometric sensor
The sticker placed on the infant’s chest measures heart rhythms in the form of an ECG as well as other vital signs like temperature and heart rate, and the one on the foot measures blood oxygenation, or the amount of oxygen present at any given time in a baby’s blood. John Rogers/Northwestern University

“We felt like if we could successfully address this set of requirements, then transitioning to consumer applications would then be far more straightforward,” says Rogers. “We decided to start with the hardest thing with the most demanding set of measurement requirements with perhaps the most difficult patients in terms of skin sensitivity and work from there.”

The biosensor system works as a pair of two devices, both operating wirelessly. They are time-synchronized with one another and stream data to an external monitor or tablet. The sticker placed on the infant’s chest measures heart rhythms in the form of an ECG as well as other vital signs like temperature and heart rate, while the one on the foot measures blood oxygenation, which is the amount of oxygen present at any given time in a baby’s blood. Though not studied in this paper, the researchers have also used the pair together to study blood pressure, by tracking the amount of time it takes for blood to flow from one sensor to another (for the chest to the foot.) And perhaps further down the line, Rogers says, they may be able to combine all the sensors into one patch that would be worn on the chest.

The sensors charge wirelessly, similar to the way a smartphone does. The transmitters rest in the bed or on a blanket that mothers can wrap around the babies when they hold them.

new wireless biometric sensor
The new sensors, displayed on a hand. John Rogers/Northwestern University

In the future, there are plans to expand these biosensor patches to adult humans, too, as well as to expand the use in premature babies. In both cases, they want to see what information can be gleaned from constant monitoring and perhaps incorporating artificial intelligence. If they can establish baseline vital signs, then they can better know when something is wrong or if the baby (or adult) is in distress. In infants in particular, the team wants to use this idea to attempt to better understand a baby’s sleeping patterns as well as whether it is crying out of hunger, tiredness, or pain.

Altogether, the technology and information that comes with it is part of a growing trend towards continuous health monitoring. And this tech, as well as others like it, might take health monitoring to another level. While devices like Apple Watches and Fitbits can track your heart rate, your ECG, and even your sleeping patterns, they are still a slightly bulky device to 24/7 use. These stick-ons, though, are far less obtrusive, and could someday provide key data to help everyone lead healthier lives. “We are reaching that critical mass where technology such as these are producing enough data where the insights are coming. Just like our genetics, informing in many ways how healthy we are, our vital signs and the data that our bodies are producing, is in some ways a digital genome,” says Xu. “I think, in the very near future, technologies such as these are going to be able to provide deeper and deeper insights.”

Claire Maldarelli

Claire Maldarelliis the Science Editor at Popular Science. She has a particular interest in brain science, the microbiome, and human physiology. In addition to Popular Science, her work has appeared in The New York Times, Scientific American, and Scholastic’s Science World and Super Science magazines, among others. She has a bachelor’s degree in neurobiology from the University of California, Davis and a master’s in science journalism from New York University's Science, Health, and Environmental Reporting Program. Contact the author here.