Rapid Fabrication of Self-Propelled and Steerable Magnetic Microcatheters for Precision Medicine.

Abstract

Minimally invasive therapies demand precise navigation through complex and delicate anatomical pathways, requiring medical tools that are small, flexible, and highly maneuverable. Here, a high-yield fabrication method for the production of magnetic tubular microrobots, tethered and untethered, with programmable magnetization, is presented. The method uses Joule heating through a template wire, enabling the fabrication of microrobots with tunable dimensions. Three device configurations are demonstrated: 1) a steerable guiding microcatheter with stiffness modulation; 2) an untethered tubular microrobot (TubeBot), exhibiting wave-crawling locomotion; and 3) a hybrid microcatheter robot that integrates distal-end wave-crawling propulsion with linear insertion to minimize tissue trauma. Validation in tortuous channels, soft phantoms replicating tissue compliance, 3D-printed organ models, ex vivo tissues, and live mice demonstrates the microrobots's ability to achieve precise navigation across different environments. The successful targeted delivery of sperm cells, embryos, and drug-mimicking compounds further highlights its potential for precision medicine, including applications in assisted reproduction and targeted drug delivery.