Magnetically Actuated Micro-Robot System for Targeted Thrombolysis in Peripheral Vascular Occlusion

Acute peripheral arterial thrombosis poses a major threat to limb salvage, and conventional thrombolytic therapies are constrained by systemic drug administration, limited local drug concentration, and elevated bleeding risk. Micro-robotic medical devices controlled by external magnetic fields have emerged as a promising platform for localized vascular intervention. This study constructs a helical magnetic micro-robot equipped with a thrombolytic-loaded porous coating, which can navigate through tortuous peripheral vasculature under remote magnetic guidance. The helical structure enables efficient propulsion in viscous blood flow, and the surface porous layer serves as a reservoir for sustained release of thrombolytic agents once the robot anchors at the thrombus site. Real-time ultrasound imaging is adopted to track the locomotion and positioning of the micro-robot in the in-vitro vascular phantom and ex-vivo vessel models. Quantitative analysis indicates that targeted delivery significantly enhances local drug concentration and accelerates thrombus dissolution while lowering the systemic drug exposure. Current challenges include the difficulty of precise real-time tracking in deep soft tissue and the scaling of fabrication for batch production. This magnetically driven micro-robot system provides a novel paradigm for site-selective thrombolysis and minimally invasive vascular therapy.