Photoacoustic and piezo-ultrasound hybrid-induced energy transfer for 3D twining wireless multifunctional implants

Abstract

Ultrasound-induced energy transfer (UET) represents an emerging technology that can be integrated into implantable medical systems for wireless power and information communication applications. However, the spatial–temporal resolution, directivity, and versatility of traditional piezo-ultrasound systems are generally limited. Here, we describe the novel design and implementation of a hybrid-induced energy transfer strategy using photoacoustic (PA) and piezo-ultrasound (PU) technology in a 3D twining wireless implant, which shows multi-mode transmission advantages, with high power, better resolution, and flexible directivity. This new ultrasonic system exploits a focused ring piezo-transducer and a miniaturized fiber-photoacoustic converter as the hybrid acoustic source and a (K,Na)NbO₃-based lead-free linear piezo-array as the harvester. Complying with FDA regulations, hybrid-induced multifunctionality, such as stable powering (∼21.3 mW cm⁻²) and the high-resolution signal communication (signal-to-noise ratio: ∼22.5 dB) of a two-dimensional image, was demonstrated ex vivo using 12 mm-thick porcine tissue. The 3D twining design also ensures that the device can achieve stable energy harvesting without operational difficulties, a unique advantage that can facilitate its future clinical application.