Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have developed a revolutionary wearable ultrasonic sensor that adapts to the shape of the body and supports both diagnostic and therapeutic applications.
Whereas conventional wearable ultrasonic systems often suffer from low power and limited structural stability, this new sensor offers a flexible and dimensionally stable design that enables accurate imaging and targeted treatment without surgical intervention.
From flexible to rigid
The research team, led by Professor Hyunjoo Jenny Lee of the Faculty of Electrical Engineering, developed a so-called ‘flex-to-rigid’ (FTR) CMUT (capacitive micromachined ultrasonic transducer) sensor. The innovation uses a low-melting-point alloy (LMPA) that liquefies when heated, making the device flexible. Once the power is turned off, the metal solidifies again, fixing the sensor in the desired curved shape.
This technique allows the sensor to accurately adapt to the contours of the body, which is essential for reliable measurements and effective therapy. This makes it possible to apply targeted ultrasound without complex beamforming electronics. The research was recently published in npj Flexible Electronics
Higher performance and stability
Compared to traditional polymer sensors, which often blur when vibrating and offer limited focus, the FTR structure combines a rigid silicon base with an elastomeric bridge. As a result, the sensor delivers higher acoustic output, sharper focus and remains stable even after repeated bending.
The system can automatically set the correct focus depending on the body shape, while remaining electrically and acoustically stable. This combination of mechanical flexibility and high signal strength is an important step towards accurate, patient-friendly medical imaging.
Potential for treatment and home application
The sensor achieves acoustic power comparable to Low-Intensity Focused Ultrasound (LIFU), a non-invasive treatment method that can stimulate tissue without causing damage. In animal studies, targeted stimulation of the spleen led to reduced inflammation and improved mobility in arthritis.
In the future, the KAIST team wants to expand the technology to a two-dimensional sensor matrix, enabling high-resolution imaging and targeted treatment at the same time. This could pave the way for a new generation of smart, wearable care systems for use in hospitals and at home.
Because the technology is compatible with existing semiconductor manufacturing processes, large-scale production and integration into wearable or home care systems is well within reach. The researchers expect this innovation to be an important step towards personalised, continuous and non-invasive medical monitoring and therapy.
Flexible ultrasound patch
Last year, TNO developed an innovative technology that allows organs to be continuously monitored via a flexible ultrasound patch (in Dutch)on the skin. This so-called PillarWave uses sound waves to create long-term images of organs, such as the heart or the circulatory system. This allows patients to be monitored at home, reducing hospital visits and lowering the workload for healthcare professionals.
The patch consists of ultra-thin plastic film with printed structures that reflect sound waves. This creates a sharp and detailed image of the body. Because the patch can take measurements over a long period of time, it provides a more reliable basis for diagnoses and can prevent unnecessary surgery.
The technology is patented and TNO is working on commercialisation through the new spin-off PillarWave, which aims to produce the patches affordably and on a large scale for applications in clinics and home care.
