Acoustically powered wireless medical implants.

摘要

Power transfer, size, and form factor are three critical design factors for next- generation implantable biomedical microdevices. Traditional powering methods such as batteries and inductive power transfer cannot satisfy conflicting requirements of large penetration depth, omni-directionality, and small size for many emerging applications. For example batteries are still large and have limited lifetime; whereas, inductive powering does not scale well into the mm and sub-mm scale, has limited range, and suffers from severe alignment sensitivity (slight misalignment between the transmitter and receiver coils results in asignificant drop in the received power). The goal of this research has been to develop and characterize several implantable biomedical microdevices that utilize acoustic/ultrasonic wave as a power source or a control signal. Acoustic/ultrasonic wave offers deeper penetration depths, omni-directionality, better scaling at mm and sub-mm dimensions, and easier fabrication process. We present three devices in this thesis; these are: 1) an acoustically- (i.e., music) powered semi-passive pressure sensor, 2) a battery-powered pressure- sensing system with an ultrasonically controlled power management module, and 3) an ultrasonically-powered micro light source for localized in situ photodynamic therapy.