Wearing the device is painless – the microparticles barely penetrate the surface of the skin to sense biomolecules in the interstitial fluid, which is the fluid that surrounds cells beneath the skin. The device can be worn on the upper arm and sends data wirelessly to a custom smartphone app.
Researchers at the UC San Diego Center for Wearable Sensors describe their device in a paper published May 9 in the journal Nature Biomedical Engineering.
“This is like a complete skin laboratory“, said center director Joseph Wang, professor of nanoengineering at UC San Diego and co-author of the paper.
“It is capable of continuously measuring multiple biomarkers at the same time, allowing users to monitor their health and wellness as they go about their daily activities.. “
Most commercial health monitors, such as continuous blood glucose monitors for diabetics, measure only one signal. The problem with that, the researchers say, is that it leaves behind information that could help people with diabetes, for example, manage their disease more effectively.
Monitoring alcohol levels is helpful because drinking alcohol can lower blood sugar levels. Knowing both of these levels can help people with diabetes prevent their blood sugar from dropping too low after drinking alcohol.
Incorporating lactate information, which can be monitored during exercise as a biomarker for muscle fatigue, is also useful because physical activity affects the body’s ability to regulate glucose .
“With our wearable, people can see how their blood sugar spikes or drops interact with diet, exercise and alcohol consumption. It can also increase their quality of life“, said Farshad Tehrani, a PhD student in nanoengineering at Wang’s lab and one of the first co-authors of the study.
Microneedles fused with electronics
Wearable devices include a microneedle patch that is connected to an electronic device case. Various enzymes on the tips of the microneedles react with glucose, alcohol, and lactate in the interstitial fluid.
These reactions generate tiny electrical currents, which are analyzed by electronic sensors and communicated wirelessly to an application the researchers have developed. Results are displayed in real time on the smartphone.
One advantage of using microneedles is that they sample interstitial fluid directly, and research has shown that biochemical levels measured in that fluid correlate well with levels in the blood.
“We’re starting in a really good place with this technology in terms of clinical validity and relevancePatrick Mercier, professor of electrical and computer engineering at UC San Diego and co-author of the paper.
The microneedle patch, disposable, can be removed from the electronic housing for easy replacement. Electronic housing, reusable, containing batteries, electronic sensors, wireless transmitters, and other electronic components. The device can be recharged on any wireless charging pad used for phones and smartwatches.
Integrating all of these components together into a small, wirelessly wearable device was one of the team’s biggest challenges. It also requires some clever design and engineering to combine reusable, always-dry electronics, with microneedle patches, that come into contact with biological fluids.
“The beauty of this is that it’s a fully integrated system that someone can wear without being tied to a desktop device.“, said Mercier, who is also co-director of the Wearable Sensor Center at UC San Diego.
The wearable was tested on 5 volunteers, who wore the device on their biceps while exercising, eating a meal, and drinking a glass of wine. The device was used to continuously monitor the blood glucose levels of the volunteers along with their alcohol or lactate levels.
Glucose, alcohol and lactate measurements taken by this device closely resemble those taken respectively by a commercial blood glucose meter, Ventilator, and blood lactate measurements taken in the laboratory. experience.
Farshad Tehrani and co-first author Hazhir Teymourian, who was a postdoctoral researcher in Wang’s lab, co-founded a startup called AquilX to further develop the technology commercially.
Next steps include testing and improving how long the microneedle patch can last before being replaced. The company is also excited about the possibility of adding more sensors to the device to monitor patient drug levels and other health signals.