A Flexible Piezo-Composite Ultrasound Blood Pressure Sensor with Silver Nanowire-based Stretchable Electrodes

Monitoring blood pressure based on ultrasound demonstrates unique advantages over many other existing techniques such as noninvasiveness, preciseness, and convenience. However, conventional ultrasonic transducers/arrays are mostly developed with a rigid front, resulting in difficulty in maintaining a conformal contact with soft human skin in a setting of wearable devices. Here, we present a flexible ultrasound blood pressure sensor which was fabricated by a piezoelectric 1-3 composite and silver nanowire-based stretchable electrodes. Due to its flexibility, this sensor can be mounted onto skin without any constriction of body movement and discomfort. The prototyped flexible sensor was evaluated for blood pressure measurements. Specifically, blood vessel diameter variations were detected and translated into blood pressure waveforms. The findings suggest a great potential of this flexible ultrasound pressure sensor for wearable sensor applications.