A team of researchers has developed a new technology for non-invasive blood pressure monitoring that does not require the use of a traditional cuff. The device uses ultrasound to track real-time changes in vascular diameter, allowing for continuous blood pressure measurement. This innovation is expected to be used in future wearable healthcare devices and smart medical monitoring platforms.
The research was led by Dr. Shin Hur at the Korea Institute of Machinery and Materials (KIMM), with participation from Syed Turab Haider Zaidi, a student researcher from the UST–KIMM School at KIMM, and Dr. Byung-Chul Lee's team at the Korea Institute of Science and Technology (KIST). They have created what they describe as "the world's first skin-attachable, noninvasive blood pressure sensor using PMN-PT single-crystal piezoelectric composites integrated through a low-temperature soldering process."
To construct the sensor, the team used a dual-side SnBi (tin–bismuth) low-temperature solder bonding technique to integrate high-performance piezoelectric devices onto a flexible substrate without depolarization. The resulting ultrasonic transducer array sends an ultrasonic beam through the skin, detects signals reflected from vessel walls, and measures changes in vessel diameter associated with systolic and diastolic blood pressure.
The sensor is built on a flexible polyimide substrate with Parylene-C encapsulation. It is less than 0.5 mm thick and weighs under 1 gram, making it suitable for long-term wear on human skin.
According to the researchers, "Existing optical cuffless blood pressure measurement technology is susceptible to external environmental factors such as skin color, movement, and lighting. It also has limitations in that it can only measure blood vessels close to the skin surface, making it unable to measure blood pressure in deep blood vessels." In contrast, their ultrasound-based approach allows direct measurement of actual diameter changes in deeper vessels beneath the skin.
Traditional ultrasonic sensors made with rigid materials often do not adhere well to curved or moving surfaces like human skin. The new device overcomes this by using PMN-PT composite material combined with low-temperature soldering for better flexibility and attachment without performance loss.
Testing was conducted using an artificial-skin vascular phantom model. The results showed systolic and diastolic blood pressures could be measured within errors of ±4 mmHg and ±2.3 mmHg respectively—meeting clinical standards set by AAMI.
The project received support from South Korea’s Ministry of Trade, Industry and Resources' Materials and Components Technology Development Program focused on developing multi-sensory sensors for service robots. Details of this research were published in January 2026 under the title "Skin-Conformal PMN-PT Ultrasonic Sensor for Cuffless Blood Pressure Sensing via Eutectic Solder Integration" in Microsystem & Nanoengineering journal.
