Magnetic soft microfiberbots for robotic embolization.

Cerebral aneurysms and brain tumors are leading life-threatening diseases worldwide. By deliberately occluding the target lesion to reduce the blood supply, embolization has been widely used clinically to treat cerebral aneurysms and brain tumors. Conventional embolization is usually performed by threading a catheter through blood vessels to the target lesion, which is often limited by the poor steerability of the catheter in complex neurovascular networks, especially in submillimeter regions. Here, we propose magnetic soft microfiberbots with high steerability, reliable maneuverability, and multimodal shape reconfigurability to perform robotic embolization in submillimeter regions via a remote, untethered, and magnetically controllable manner. Magnetic soft microfiberbots were fabricated by thermal drawing magnetic soft composite into microfibers, followed by magnetizing and molding procedures to endow a helical magnetic polarity. By controlling magnetic fields, magnetic soft microfiberbots exhibit reversible elongated/aggregated shape morphing and helical propulsion in flow conditions, allowing for controllable navigation through complex vasculature and robotic embolization in submillimeter regions. We performed in vitro embolization of aneurysm and tumor in neurovascular phantoms and in vivo embolization of a rabbit femoral artery model under real-time fluoroscopy. These studies demonstrate the potential clinical value of our work, paving the way for a robotic embolization scheme in robotic settings. Editor's summary: As a minimally invasive treatment for aneurysms and brain tumors, surgeons typically insert a slender catheter through the femoral artery and guide it through blood vessels to deliver embolic agents. However, this method of embolization can be difficult to steer through complex vascular networks. A magnetic, soft microfiberbot was developed by Liuet al. to perform remotely controlled robotic embolization. The microfiberbot, composed of a magnetized fiber coiled into a helix shape, can conform to different vessel sizes and performs a corkscrew propulsion when subjected to an external magnetic field. The microfiberbots were used to successfully perform in vitro embolization of aneurysm and tumor in phantom blood vessels and in vivo embolization in a rabbit femoral artery. These proposed robots provide a controllable alternative to conventional catheter-based embolization. —Melisa Yashinski [ABSTRACT FROM AUTHOR]