Multi-Material 3D-Printed Magnetic Millirobot for Quadrupedal Locomotion in Endoluminal Spaces

This work presents a quadrupedal magnetic millirobot, termed “beamrobot”, fabricated via a multi-material direct ink writing (DIW) technique for agile locomotion in confined endoluminal environments. Inspired by the stable gait of geckos, the robot features a soft central body and four programmable magnetic feet, which enable controlled shape-morphing and motion under external magnetic fields. A customized DIW system allows simultaneous printing of silicone and hard-magnetic composites, achieving integrated structuring and directional magnetization in a single process. The robot exhibits multiple deformation modes and directional crawling under combined magnetic fields, navigating U-shaped paths, traversing obstacles, and clearing simulated thrombus in vascular models. This design offers a new paradigm for creating miniaturized, untethered robots with potential for minimally invasive medical operations.

Magnetically Steerable Hard-Magnetic Guidewire for Endovascular Navigation

    This work presents a magnetically steerable hard-magnetic guidewire for precise and remote-controlled navigation in tortuous endovascular environments. The guidewire is fabricated via direct ink writing (DIW) of an Ecoflex–NdFeB composite, followed by magnetization and hydrogel encapsulation, enabling programmable magnetic response and biocompatible flexibility. Integrated with a 7-degree-of-freedom (7-DOF) magnetic navigation system consisting of a robotic arm–mounted permanent magnet and servo-controlled mechanical actuation, the guidewire achieves controllable three-dimensional bending, orientation, and advancement within vascular phantoms. A customized guidewire advancer employing a servo-driven friction gear mechanism allows synchronized axial motion, ensuring stable manipulation during navigation. A Cosserat rod–based theoretical framework coupled with a damped Newton solver quantitatively predicts the magnetic–elastic deformation behavior, showing strong agreement with experimental observations. The proposed system demonstrates a fully integrated platform that combines hard-magnetic actuation, mechanical modeling, and robotic control, offering a promising approach toward next-generation minimally invasive endovascular interventions.