Dual-coil magnetic guidewire robot: a new smooth steering solution for vascular interventional navigation

Magnetically steerable guidewires are widely studied because they enable remote, minimally invasive navigation and allow distal tip shaping without relying solely on proximal pushing and twisting. This is especially valuable in tortuous, branching anatomy, where better steering can improve reach and reduce mechanical trauma. Still, practical limitations remain. When an external field couples directly to a magnetic tip, the guidewire may react too abruptly, leading to transient jumps or unstable deflections that are hard to anticipate and may irritate the vessel wall. Coil-based designs offer finer control because magnetic output is current-tunable and can be turned off instantly, but many single-coil tips still struggle with limited deflection and weak axial force transmission. These limitations become most apparent at bifurcations, where the guidewire must align gently with a side branch while still advancing without buckling.

Scientists at Nankai University developed a dual-coil magnetic guidewire robot to make steering more adaptable to different navigation tasks. The distal tip integrates two independently driven microcoils, while a robot positions an external permanent magnet to provide a controllable background field. By adjusting current direction and magnitude, the guidewire switches among three modes. Dual-attraction and dual-repulsion focus on wide-range curvature control and steadier advancement, improving pushability by enhancing axial force transmission to the distal segment and reducing buckling risk. The spoon-shaped mode targets delicate maneuvers near branches by creating a gradual, continuous bend that supports smoother alignment and reduces localized contact during branch engagement.

To check practical feasibility, the authors assessed thermal safety in a warm circulating water bath that mimics body conditions and observed only a small temperature rise during continuous actuation within commonly used safety limits. They then tested steering in a 90 degree glass channel representing sharp turns and branch entry. Single-coil actuation showed limited bending and occasional sudden slips after buckling. With dual-attraction and dual-repulsion, the guidewire achieved a wider bending range and more stable turning. For fine alignment, the spoon-shaped mode helped the tip approach the branch smoothly with less wall contact and rebound, followed by a switch to dual-attraction for decisive entry. In a transparent aortic arch phantom, the guidewire repeatedly reached multiple target branches, showing reliable mode transitions in realistic vascular geometry.

Overall, the study shows that a dual-coil distal architecture, paired with an external permanent magnet and independent current control, can provide strong steering for rapid corrections and smoother curvature shaping for branch-level maneuvers. Real vascular navigation is not a single task, it alternates between fast reorientation, steady advancement, and fine alignment. Embedding these capabilities into the distal structure and control logic can improve reliability and usability for robotic endovascular navigation. Clinically, it could support safer and more consistent procedures by improving distal controllability, reducing unintended vessel-wall interaction, and enhancing access to small, tortuous, and branching targets.