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 piezo‐ultrasound 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, frequency‐controlled 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.