Silicon nanocolumn-based disposable and flexible ultrasound patches

Traditional wearable ultrasound devices pose challenges concerning the rigidity and environmental impact of lead-based piezoelectric materials. This study proposes a silicon nanocolumn capacitive micromachined ultrasonic transducer (snCMUT) array for real-time wearable ultrasound imaging in disposable patches. Using a lead-free design, snCMUT incorporates silicon nanocolumns to address existing issues and achieves high transmission efficiency (220 kPa/V), flexibility, and low power consumption. The specialized structure of snCMUT enhances displacement efficiency, enabling high-resolution imaging while maintaining a thin, flexible form factor (~900 μm). Phantom imaging demonstrates its superior performance, with high axial and lateral resolutions (0.52 and 0.55 mm) and depth penetration (~70 mm) at low voltage (8.9 V_PP). Upon successful application to monitor both sides of the human carotid arteries, snCMUT offers clear ultrasound images and continuous blood pressure waveform monitoring. This proposed innovation presents significant potential for continuous medical imaging and cardiovascular health assessment, addressing environmental concerns and reducing manufacturing costs (<$20).