Magnetic Milli-Spinner for Robotic Endovascular Surgery.

Navigating the complex and high-flow environment of human vasculature remains a major challenge for conventional endovascular tools and externally actuated tethered systems. While catheter-based approaches are the clinical standard, their limited steerability and force transmission hinder access to tortuous or distal vessels, especially in the brain. Untethered robotic systems have emerged as a promising alternative for enhanced flexibility and reachability. However, most designs struggle against the high, pulsatile blood flow in human arteries. Here, the study presents a magnetically actuated milli-spinner robot that overcomes existing limitations in navigating complex and high-flow vasculature. Capable of swimming at 23 cm·s-1 (73 body lengths per second), the milli-spinner enables rapid, stable navigation through complex vasculature. This performance is driven by its hollow cylindrical structure with integrated helical fins and slits, which together generate a spinning-induced flow field that enhances propulsion efficiency and allows the robot to maintain stability and control even in dynamic, pulsatile blood flow environments. In addition to its navigation capabilities, the milli-spinner enables multifunctional treatment, including localized suction and shear for efficient clot removal, targeted drug delivery, and in situ embolization for aneurysm treatment. These features establish the milli-spinner as a versatile and powerful platform for next-generation, untethered endovascular interventions.