Wearable electronics for mechanical and acoustic assessment of deep tissues

Abstract

Continuous monitoring of deep-tissue structure and mechanics remains a fundamental challenge in wearable healthcare. Wearable acoustic sensing provides a unique opportunity. This dissertation develops wearable acoustic electronics that span from mechano-acoustic wave (MAW) sensing to four-dimensional ultrasound imaging. The wireless MAW platform uses a pair of inertial measurement units (IMUs) to detect broadband elastic waves generated by a skin-mounted vibration actuator in real time, quantifying deep-tissue stiffness without the need for calibration across subjects through surface-wave dispersion analysis. A soft two-dimensional ultrasound array integrated with a liquid-metal–based shape sensor is introduced to achieve conformal, deformation-tolerant imaging of deep tissues. Validation in phantoms, ex vivo tissues, and on-body studies demonstrates stable performance of these technologies with clinical significance. Collectively, these advances transform acoustic technologies from episodic diagnostic tools into wearable, deformation-adaptive platforms for continuous deep-tissue monitoring in point-of-care and home-based settings, holding potential to enable ambulatory assessment for rehabilitation, fatigue monitoring, injury prevention, and wearable robotics.