Ultrasonic Selective Opening of Microcavities for Drug Delivery Microimplants

We present a fully passive, ultraminiaturized drug delivery microchip that enables wireless, on-demand release via ultrasonic actuation - a mechanism not previously demonstrated in implantable drug delivery systems. By eliminating the need for integrated power and control components, the device achieves sub-millimeter dimensions (<0.2> $\times 0.5$ mm $\times 1$ mm), enabling minimally invasive implantation in sensitive or hard-to-reach tissues. The system relies on ultrathin metallic membranes (<100> $\mu $ m wide, <200> $2~\mu $ g of powder payload from individual microcavities in response to specific frequencies (360/420/580 kHz), with membrane rupture occurring in in vivo conditions at ultrasonic intensities within clinically safe limits (<150>²). This platform represents a significant step toward precise, programmable drug delivery in anatomically constrained or delicate regions.[2025-0104]