A research team led by Professor Sung Hoon Kim from Korea University has developed the world's first alginate-based microrobots that can be tracked using Magnetic Particle Imaging (MPI).
The newly developed system, reported in the International Journal of Extreme Manufacturing , marks a major milestone in microrobotics by enabling real-time localization, selective thermal therapy, and cell delivery—all powered and controlled through a single magnetic actuation system, completely independent of conventional medical imaging devices such as cameras, CT, or X-ray machines.
The research team engineered an advanced calcium alginate hydrogel microrobot by embedding two types of magnetic materials— superparamagnetic iron oxide nanoflowers (SPNF) and NdFeB (neodymium-iron-boron) microparticles —into the hydrogel matrix. Unlike previous microrobots that relied on a single magnetic component, this synergistic combination enabled the world's first triple-functional magnetic hydrogel robot , capable of:
Traditional microrobot tracking has relied heavily on CT, X-ray , or camera-based systems , which come with several limitations including radiation exposure, high cost, and poor compatibility with in vivo environments. In contrast, this new robot utilizes MPI , a novel and emerging magnetic imaging modality, to track both the position and magnetic concentration of the robot in real-time, without the need for radiation or optical devices.
The microrobots were successfully used to deliver and release therapeutic cells , guided precisely to target areas, and to induce localized heating upon arrival for potential oncological or regenerative applications . The researchers also demonstrated cell viability and growth after delivery, validating the robot’s therapeutic potential.
Even within a flowing fluid phantom mimicking physiological blood flow (up to 50 mm/s ), the robot maintained stable locomotion and positional accuracy , underscoring its robustness for eventual in vivo clinical applications .
Professor Kim emphasized the significance of the study, stating:
“This research goes beyond the conventional concept of magnetic robots performing imaging, actuation, and therapy as separate systems. We’ve successfully demonstrated an all-in-one platform that integrates all functions into a single, compact electromagnetic coil system , laying the groundwork for the next generation of magnetically actuated theranostic systems .”
The work paves the way for a variety of high-impact biomedical applications, including precision cancer therapy, neural stimulation, and localized cell-based treatment .
Looking ahead, the team plans to validate the robot further through long-term biological testing and animal models , with the vision of creating a fully autonomous, image-free intelligent microrobot capable of navigating, treating, and tracking inside the human body— without the aid of cameras or CT scanners .
International Journal of Extreme Manufacturing (IJEM, IF: 21.3 ) is dedicated to publishing the best advanced manufacturing research with extreme dimensions to address both the fundamental scientific challenges and significant engineering needs.
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International Journal of Extreme Manufacturing
Fabrication of MPI-traceable alginate magnetic millirobots with multimodal selective-locomotion and heating capabilities
17-Jul-2025