Innovative Ultrasonic Sensor Transforms Cuffless Blood Pressure Monitoring

A groundbreaking technology has emerged, enabling cuffless and non-invasive blood pressure monitoring through ultrasonic methods. This innovative sensor tracks real-time changes in vascular diameter without the need for traditional cuffs, marking a significant advancement in wearable healthcare devices and smart medical monitoring platforms.

The research team, led by Dr. Shin Hur at the Korea Institute of Machinery and Materials (KIMM), collaborated with Dr. Byung-Chul Lee’s team at the Korea Institute of Science and Technology (KIST). They developed the world’s first skin-attachable, non-invasive blood pressure sensor utilizing PMN-PT single-crystal piezoelectric composites. This technology integrates high-performance piezoelectric devices onto a flexible substrate through a low-temperature soldering process, ensuring both effectiveness and comfort.

The sensor features a 5×4 array structure ultrasonic transducer array (UTA). It operates by transmitting ultrasound generated by PMN-PT single-crystal 1–3 composites into blood vessels, detecting signals reflected from vessel walls. This allows the sensor to measure real-time changes in blood vessel diameter, which correspond to systolic and diastolic blood pressure readings.

Advancements in Design and Functionality

Constructed on a flexible polyimide (PI) substrate and encapsulated with Parylene-C, the sensor is designed for long-term wearability. With a thickness of under 0.5 mm and a weight of less than 1 g, it adheres securely to the skin. The dual-side low-temperature solder bonding technique prevents thermal depolarization, which is commonly associated with lead-based piezoelectric devices. This method guarantees a high signal-to-noise ratio (SNR) and reliable electrical bonding without requiring high-temperature processing.

Current optical cuffless blood pressure technologies face challenges related to external environmental factors such as skin color, movement, and lighting. These systems can only measure blood vessels close to the skin surface, thus limiting their effectiveness. In contrast, the ultrasonic technology can accurately measure diameter changes in deeper blood vessels, providing a more reliable assessment of blood pressure.

Traditional ultrasonic sensors, often made from rigid PZT materials, struggle with wearability. The PMN-PT composite used in this new sensor overcomes these limitations, allowing for a conformal attachment to the skin without sacrificing performance. The streamlined structure also enhances manufacturing efficiency while maintaining excellent SNR.

Validation and Future Applications

The sensor achieved remarkable accuracy, with systolic and diastolic pressure measurements showing errors of ±4 mmHg and ±2.3 mmHg, respectively. These results align with the AAMI clinical standard of ±5 mmHg, representing one of the highest accuracy levels reported for non-invasive ultrasonic blood pressure monitoring.

“This technology is the first to demonstrate continuous, cuff-free blood pressure monitoring using a skin-attachable ultrasonic sensor,” stated Dr. Shin Hur. “When combined with AI-based blood pressure analysis, it will evolve into a core platform for personalized cardiovascular disease prediction and smart healthcare.”

The development of this non-invasive blood pressure sensor was supported by the Ministry of Trade, Industry and Resources’s Materials and Components Technology Development Program. The research findings were published in January 2026 under the title “Skin-Conformal PMN-PT Ultrasonic Sensor for Cuffless Blood Pressure Sensing via Eutectic Solder Integration” in the journal Microsystem & Nanoengineering, which ranks first in the Instruments & Instrumentation category.

The advancements made by the KIMM team could pave the way for a new era in blood pressure monitoring, enhancing patient care and leading to more personalized healthcare solutions.