The microscopic robots lift an object. (Credit: Device)
Meet the magnetic ‘microrobot’ that could change how we deliver medicine
In a nutshell
- Scientists developed microscopic magnetic robots that work together in swarms, performing tasks like climbing walls, transporting heavy objects, and clearing blocked tubes—potentially revolutionizing minimally invasive medical procedures
- Each robot is smaller than a grain of salt but can lift objects 2,000 times its weight when working in swarms of up to 1,000 robots
- The robots can self-organize into different formations using magnetic fields, similar to how ants work together, though they currently require external control and cannot navigate autonomously
SEOUL, South Korea — What if doctors could deploy thousands of tiny robots to clear blocked arteries? Scientists at Hanyang University have taken a significant step toward this future by developing microrobots that self-organize into swarms, tackle obstacles, and transport heavy cargo.
Research published in the journal Device reports that these microscopic robots work together like ant colonies to accomplish remarkable feats. Each is smaller than a grain of salt and demonstrates surprising adaptability to their surroundings while working collectively to solve complex challenges.
Think of each robot as a tiny magnetic brick. Using a process similar to making ice cubes, researchers can produce hundreds of these robots simultaneously in a cost-effective way. They use replica molding and magnetization to ensure uniform geometry in each tiny robot.
Each robot stands 600 micrometers tall (about half a millimeter) and contains specially embedded magnetic particles called neodymium-iron-boron (NdFeB). These particles allow the robots to respond to magnetic fields and interact with their neighbors. When exposed to a magnetic field created by rotating magnets, the robots automatically arrange themselves into different formations.
The different tasks the robots can perform. (Credit: Device).
They can arrange themselves in three main ways: end-to-end like a train (head-to-tail), overlapping like roof shingles (slipped-co-facial), or face-to-face like magnets on a refrigerator. Previous swarm robotics research focused on spherical robots that could only connect point-to-point. These cube-shaped robots create stronger connections since entire faces can touch, similar to how magnets stick together more strongly when their full surfaces meet.
Eight robots linked together could climb walls five times their height. Some swarms could launch individual robots over barriers, while others could transport objects across water that weighed 2,000 times more than the robots themselves.
In one striking demonstration, a swarm of 1,000 robots formed a floating raft on the water’s surface. The swarm then wrapped itself around a pill weighing 2,000 times more than each individual robot, successfully transporting the payload across the liquid. This behavior mirrors how fire ants form living rafts to survive floods—an example of how engineers often draw inspiration from nature.
On land, the swarms could transport cargo 350 times heavier than individual robots. They even cleared blocked tubes by working together to break up the obstruction, which simulates how they might one day clear clogged arteries.
Ants swarm to create raft-like structures during floods, much like the robots in the study. (Gmork/Shutterstock)
The robots can also interact safely with living creatures. By moving in coordinated patterns, robot swarms gently guided ants and pill bugs in specific directions without harming them. They even created a feeding control system for larger creatures like superworms by strategically blocking and allowing access to food.
Controlling these robot swarms is like conducting an invisible orchestra with magnets. By rotating magnetic fields around the robots, researchers can make them spin in place or move in circular patterns. Changing the magnetic field’s strength lets them switch between different movement styles.
“The magnetic microrobot swarms require external magnetic control and lack the ability to autonomously navigate complex or confined spaces like real arteries,” says study author Jeong Jae Wie from Hanyang University’s Department of Organic and Nano Engineering, in a statement. “Future research will focus on enhancing the autonomy level of the microrobot swarms, such as real-time feedback control of their motions and trajectories.”
VIDEO: Watch the microrobots lift heavy objects and hurl themselves over objects
As researchers work to give these microrobot swarms more autonomy, the technology moves closer to practical applications in medicine, manufacturing, and environmental cleanup. The key challenge remains developing systems that allow these tiny robots to navigate and make decisions independently.
Paper Summary
Methodology
The researchers used a microstereolithography 3D printer to create a negative mold with hundreds of cuboid-shaped cavities. They then filled this mold with a mixture of epoxy and magnetic particles, applied a sacrificial coating, and exposed the robots to specific magnetic fields to program their behavior. This allowed mass production of identical robots with precisely controlled magnetic properties.
Results
The microrobot swarms demonstrated multiple capabilities:
- Climbing obstacles 5x their height
- Throwing robots over 7mm barriers at speeds up to 1,080 body lengths per second
- Lifting objects 1,600 times heavier than individual robots
- Transporting cargo across water and land
- Manipulating liquid metals despite high surface tension
- Unclogging blocked tubes
- Guiding living organisms
Limitations
The current system requires external magnetic field control and lacks autonomous navigation capabilities. The robots cannot yet sense their environment or make independent decisions. Additionally, while the manufacturing process can produce hundreds of robots, scaling to even larger swarms may present challenges.
Discussion and Takeaways
This work shows how relatively simple microrobots can achieve complex behaviors through collective action. The ability to program different swarm configurations for specific tasks demonstrates a new level of control in microscale robotics. While practical applications are still years away, this research establishes important principles for developing future microscale robotic systems.
Funding and Disclosures
The research was supported by the Nano & Material Technology Development Program through South Korea’s National Research Foundation, with additional funding from the Asian Office of Aerospace Research and Development.
Publication Details
Published in Device (Volume 3, Issue 100626) on April 18, 2025. Authors include Kijun Yang, Sukyoung Won, Jeong Eun Park, Jisoo Jeon, and Jeong Jae Wie from various departments at Hanyang University and collaborating institutions.
