Magnetically Actuated Hydrogel-Based Microrobotic Structures with X-Ray Visibility for Targeted Drug Delivery in Vascular Environments

In recent years, microrobots have attracted attention as minimally invasive therapeutic tools in biomedical applications, as they enable enhanced drug delivery efficiency through direct and localized transport. However, practical realization requires highly precise controllability and real-time responsiveness. In this study, we present a hydrogel-based microrobotic structure precisely and dynamically controlled in real time using externally applied magnetic fields. Chemical, structural, and magnetic characteristics were systematically analyzed, followed by experimental evaluation of targeting performance within a vascular-mimicking model under a phosphate-buffered saline (PBS) environment. Results demonstrate that sufficient visibility in X-ray imaging can be achieved depending on the concentration of embedded magnetic nanoparticles introduced during fabrication. Moreover, stable and real-time targeted navigation of the microrobotic structures was confirmed within specific threshold ranges of magnetic field strength and frequency. By effectively restricting off-target motion, the proposed system offers a minimally invasive medical platform that simultaneously ensures high stability and control precision.