This work presents an ultrasound-driven, self-powered sensing platform for battery-free monitoring in tissue-like environments, enabling a pathway toward future implantable operation. The system includes ultrasound energy-harvesting devices, a high-efficiency power-management circuit, and an ultralow-power integrated sensing-and-transmission module. A dual-triboelectric-nanogenerator (dual-TENG) architecture decouples energy delivery from command reception: a large TENG harvests acoustic energy for power, while a small TENG detects an encoded ultrasound command. Harvested energy is rectified, stored, and regulated into stable DC rails. This decoupling enables robust operation under interference and minimizes unnecessary wake-ups. In parallel, the small-TENG signal is conditioned using an ultralow-power op-amp and a nano-power hysteresis comparator to improve noise immunity and generate robust digital triggers, enabling command-gated operation in which the microcontroller remains in low-power mode and wakes only upon valid commands to sense and transmit. An end-to-end workflow was implemented and experimentally validated, including command detection/decoding, real-time temperature and humidity sensing, and wireless data transmission. The large TENG delivered 2.2 mW of stable output power, while duty-cycled control achieved 407 µW average consumption. Ex vivo porcine tissue tests confirmed reliable operation under tissue-relevant attenuation; sensed temperature and humidity were decoded and visualized in real time via a MATLAB app. These results demonstrate the feasibility of ultrasound-powered, ultralow-power, command-driven sensing in attenuating media and lay the groundwork for implantable long-term monitoring and closed-loop biomedical applications.
Pengchong Xu (2026) studied this question.