Segmented Therapeutic Delivery via Acoustic Microbubble Relay

Conventional medical microcatheters, characterized by their stiff, continuous hollow tube design, encounter inevitable mechanical constraints when delivering therapeutic agents through tortuous, highly curved, and narrowing microvascular networks. To overcome this constraint, we introduce an acoustic microbubble‐powered segmented delivery system. This microdevice utilizes oscillating microbubbles confined within discrete 3D‐printed microchannels, interconnected via rotary microhinges. Under ultrasonic excitation, these series‐connected bubble units generate directional acoustic streaming, enabling the targeted delivery of diverse microcargos. Tilted bubble arrays under ultrasound produce asymmetric vortices, breaking flow symmetry and establishing net streamlines that drive unidirectional movement across open channels. Comprehensive experimental and theoretical analyses reveal frequency‐dependent flow regimes, with a resonant peak at 102 kHz achieving delivery velocities up to 630 nL/min at 40 V _pp . Geometric optimization reveals a linear correlation among delivery efficiency, acoustic voltage, and bubble quantity and identifies an optimal microchannel length that enhances performance by minimizing vortex interference. Critically, the system enables segmented acoustic delivery around sharp bends (>90°), maintaining hydrodynamic continuity through modular units connected at variable interunit angles. A dual‐bubble configuration achieves 100% delivery success across diverse materials and high‐curvature conditions. This approach decouples delivery efficacy from catheter stiffness, providing a mechanically flexible and reconfigurable solution for complex luminal geometries.