Multichannel Piezo‐Ultrasound Implant with Hybrid Waterborne Acoustic Metastructure for Selective Wireless Energy Transfer at Megahertz Frequencies

Abstract

Ultrasound energy transfer (UET) is developed and integrated into various bioelectronics with diagnostic, therapeutic, and monitoring capabilities. However, existing UET platforms generally enable one function at a time due to the single ultrasound channel architecture, limiting the full potential of bioelectronics that requires multicontrol modes. Here, a multichannel piezoultrasound implant (MC-PUI) is presented that integrates a hybrid waterborne acoustic metastructure (HWAM), multiple piezo-harvesters, and a miniaturized circuit with electronic components for selective wireless control via ultrasound frequency switching. The HWAM that utilizes both a 3D-printed air-diffraction matrix and a half-lambda Fabry-Perot resonator is optimized to provide the advantage of ultrasound selectivity at megahertz frequencies. Complying with U.S. Food and Drug Administration regulations, frequencycontrolled multifunctional operations, such as wireless charging (≈11.08 µW) at 3.3 MHz and high-sensitivity wireless switch/control (threshold ≈0.55 MPa) of micro-light-emitting diode/motor at 1 MHz, are demonstrated ex vivo using porcine tissue and in vivo in a rat. The developed MC-PUI enhances UET versatility and opens up a new pathway for wireless implant design.

Multiscale Structure Engineering for High-Performance Pb-Free Piezoceramics

“…Moreover, fabricating incipient electronic devices using Pb-free piezoceramics is more important than ever, which has not been largely studied yet. Studying the real behavior during applications (e.g., performance, cost, and lifetime) is crucial for evaluating the electronic devices and guiding the material study, which should be given more effort. Except for the traditional applications, piezoceramics are recently explored to show the potential in other applications, such as energy storage, electrocaloric, piezoelectric nanogenerators, ferroelectric photovoltaic, piezocatalytic, biomedicine, and nonvolatile memories. ,− These new possible applications make piezoceramics more intriguing than ever, which should be further studied in the future. …”

“…Except for the traditional applications, piezoceramics are recently explored to show the potential in other applications, such as energy storage, electrocaloric, piezoelectric nanogenerators, ferroelectric photovoltaic, piezocatalytic, biomedicine, and nonvolatile memories. ,− These new possible applications make piezoceramics more intriguing than ever, which should be further studied in the future.…”

Flexible lead-free piezoelectric arrays for high-efficiency wireless ultrasonic energy transfer and communication

“…As an emerging wireless transfer technology, ultrasonic energy transfer and communication (UETC), which uses traveling ultrasonic waves to transmit energy, has been exploited and incorporated into various IMEs for wireless power supply, medical monitoring, and information communication. [17][18][19] The use of ultrasound in medical diagnosis has been widely accepted. Compared to electromagnetic waves, ultrasonic waves offer a higher FDA limit for power flux (0.72 W cm À2 vs. 0.01 W cm À2 ), 20 lower attenuation (E0.5-1 dB cm À1 MHz À1 ) through tissue, 21 much shorter wavelengths (five orders of magnitude smaller at similar frequencies) for more efficient coupling to miniaturized implants, 17 and higher security in cyber communications.…”

“…Compared to electromagnetic waves, ultrasonic waves offer a higher FDA limit for power flux (0.72 W cm −2 vs. 0.01 W cm −2 ), 20 lower attenuation (≈0.5–1 dB cm −1 MHz −1 ) through tissue, 21 much shorter wavelengths (five orders of magnitude smaller at similar frequencies) for more efficient coupling to miniaturized implants, 17 and higher security in cyber communications. 19 Additionally, outside ultrasound sources can provide adjustable and long-term continuous power delivery, regardless of the implant site and organ shape. UETC for powering and communicating IMEs via triboelectricity and piezoelectricity has been demonstrated.…”

Potassium Sodium Niobate-Based Lead-Free High-Frequency Ultrasonic Transducers for Multifunctional Acoustic Tweezers

“…Because of their fast response, wide bandwidth, and high sensitivity, increasing numbers of novel devices based on piezoelectric ultrasonic transducers have attracted people’s attention, including ultrasound imaging, therapeutic and surgical ultrasound including acoustic tweezers, , high intensity focused ultrasound, drug delivery, microfluidic channels, ultrasound-induced wireless energy transfer and communication, − etc. In personalized medicine, contact-free “microscopic handle” techniques require enhanced complex and precise operations with visualized edges, or small details of objects .…”