Every heartbeat pushes pressure through your arteries, and that pressure shifts from moment to moment. Yet most people still measure it with a cuff that squeezes the arm, then stops. A research team in South Korea now reports a thin, skin-attachable ultrasound patch that tracks blood pressure continuously, without a cuff, by watching blood vessels expand and contract in real time.
The device comes from researchers led by Dr. Shin Hur at the Korea Institute of Machinery and Materials, working with Syed Turab Haider Zaidi of the UST–KIMM School and collaborators led by Dr. Byung-Chul Lee at the Korea Institute of Science and Technology. Their study describes what they call the world’s first skin-attachable, noninvasive blood pressure sensor built with PMN-PT single-crystal piezoelectric composites and a low-temperature soldering process.
The promise is simple to feel in daily life. Blood pressure changes while you sleep, walk, stress, and recover. A cuff gives snapshots. A wearable patch could show the whole story.
You already know the tradeoff. A cuff can be accurate, but it feels bulky and inconvenient. It also tends to measure at set times, not continuously. That leaves gaps that matter for people who need close monitoring.
Many cuffless approaches rely on light, often as optical sensors. The research team notes that optical methods can struggle with outside factors like skin color, movement, and lighting. Those systems also face limits in how deep they can “see” beneath the skin. That depth matters, because you may want pressure readings from deeper vessels, not only those close to the surface.
The team argues ultrasound can solve key pieces of that puzzle. Ultrasound can reach deeper into tissue. It can also measure physical changes in vessel diameter directly, rather than guessing from surface signals. That direct measurement sits at the center of the new patch.
The sensor sends an ultrasonic beam into the body. That beam reflects off vessel walls. The device reads those echoes and tracks changes in vascular diameter. From those diameter shifts, it calculates systolic and diastolic blood pressure.
The design uses a 5×4 ultrasonic transducer array, called a UTA, built on a flexible polyimide substrate. A Parylene-C encapsulation layer covers the system. The full patch stays under 0.5 millimeters thick and weighs less than 1 gram, which aims to make long wear realistic.
At the heart of the device sits PMN-PT, short for Lead Magnesium Niobate–Lead Titanate. The team describes PMN-PT as a single-crystal piezoelectric material with exceptionally high electromechanical properties. In practical terms, the material helps the patch create and detect ultrasound signals with strong sensitivity.
That sensitivity matters because the device must detect small, fast changes in vessel walls. The researchers also emphasize signal quality. They report a high signal-to-noise ratio, or SNR, which supports clearer readings from reflected echoes.
Wearable ultrasound faces a stubborn challenge. Traditional rigid materials do not fit comfortably on curved, moving skin. The team also warns about a materials problem in lead-based piezoelectrics. High heat can depolarize the material and weaken performance.
To get around that, the researchers used a dual-side SnBi low-temperature solder bonding technique. SnBi refers to tin and bismuth. The approach keeps processing below 150 degrees Celsius, which the team says helps avoid thermal depolarization. It also allows them to integrate high-performance piezoelectric devices onto a flexible substrate.
They also ran multi-physics simulations using COMSOL to optimize acoustic propagation and reflection. Those simulations helped the team tune how sound travels through the layers and how echoes return from vessel walls.
The researchers highlight another practical benefit. They say the simplified structure maintains excellent SNR without acoustic matching or backing layers. That choice could improve manufacturing efficiency.
To validate the sensor, the team tested it using an artificial-skin vascular phantom. That setup mimics a vessel under skin-like material and lets researchers compare readings in a controlled way.
The results hit a key benchmark the team chose to emphasize. The measured systolic and diastolic pressures showed errors of ±4 mmHg and ±2.3 mmHg, respectively. The researchers say those numbers meet the AAMI clinical standard of ±5 mmHg. They also describe the performance as one of the highest accuracy levels reported for noninvasive ultrasonic blood pressure monitoring.
In everyday terms, those error ranges suggest the patch can stay close to reference values while it runs continuously. That is the difference between a device that feels like a demo and one that could someday support real decisions.
“This technology is the first to demonstrate continuous, cuff-free blood pressure monitoring using a skin-attachable ultrasonic sensor,” said Dr. Shin Hur of KIMM. “Combined with AI-based blood pressure analysis, it will evolve into a core platform for personalized cardiovascular disease prediction and smart healthcare.”
The project received support from the Ministry of Trade, Industry and Resources’ Materials and Components Technology Development Program, under a project focused on multi-sensory sensors for service robots. The team’s paper carries the title “Skin-Conformal PMN-PT Ultrasonic Sensor for Cuffless Blood Pressure Sensing via Eutectic Solder Integration.”
If this approach holds up beyond lab validation, you could see blood pressure move from occasional checks to continuous awareness. A thin patch could support long-term tracking at home, at work, and during sleep. That kind of stream can reveal patterns that single readings miss, including short spikes and quiet dips. It may also help clinicians judge treatment response with more detail, since they would not rely only on clinic visits.
The work also gives researchers a concrete platform to improve. The team links the patch to future AI-based analysis, which could turn raw vessel motion into smarter insights. That could support personalized risk prediction for cardiovascular disease, especially if the system learns how your pressure behaves under different conditions. Over time, that kind of feedback could guide earlier interventions and better monitoring plans.
On the engineering side, the low-temperature solder integration method could influence how other flexible medical sensors are built. You may see this technique used to attach sensitive high-performance materials to wearable platforms without damaging them. That could speed development of new monitoring tools beyond blood pressure, especially tools that need strong signals and comfortable wear.
Research findings are available online in the journal Microsystems & Nanoengineering.
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