A magnetic nanorobot with guided aggregation and thrombin-triggered coagulation for endovascular embolization

Current endovascular embolic agents face challenges in achieving precise localization and targeted embolization. Herein, we report a novel magnetic nano-embolization robot (MNER) that integrates real-time magnetic aggregation with thrombin-triggered coagulation, enabling a transition from passive diffusion to magnetically controlled focal embolization. The MNER features a core-shell structure with a magnetic core and a thrombin outer layer. Upon endovascular injection, MNER aggregates at the target sites under magnetic guidance, while surface-anchored thrombin triggers fibrin polymerization, promoting the rapid formation of stable blood clotting and localized embolization. The MNER exhibits excellent magnetic response in static and circulating fluid environments in vitro. In rabbit models, the MNER achieved effective and sustained embolization in renal arteries (≈3 mm) without migration or recanalization, and enabled precise occlusion in hemorrhagic mesenteric arteries with complex branches. Owing to its easy usage, biocompatibility, and potent embolization, the MNER represents a promising next-generation platform for endovascular embolization, enabling to achieve precise local retention at the target site via magnetic aggregation in conjunction with catheter-based delivery.