Ultrasonically Powered Implantable Microdevice Platform for Wireless In-Situ Multimodal Cancer Therapy

A millimeter scale, a three-dimensional ultrasonic receiver using Barium titanate (BTO) nanoparticles in a pyramid structure is presented as a wireless microsystem platform. The pyramid shape enhances the coupling of piezoelectric and flexoelectric effects, enabling efficient energy conversion. Under ultrasound, the device generates ~10 V, an order of magnitude higher than the cuboidal receiver (with the same volume). As for the proof-of-concept, the pyramid receiver enables multimodal cancer therapy, which delivers light and oxygen directly to targeted sites. A simultaneous in-situ generation of light (I = 10.1 mW/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>) and oxygen <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(6.86 \ \mu \text{mol}/\mathrm{L}/\min)$</tex> is demonstrated. These levels are adequate to reverse tumor hypoxia during photodynamic therapy, demonstrating the system's potential for multifunctional cancer treatment through wireless powering.