A revolutionary 3D printing method turns thin magnetic films into “muscles” that can make foldable robots move — opening new possibilities for medicine, science, and beyond.
Imagine a tiny robot that can fold itself like origami, travel through your body, unfold when it reaches a wound or ulcer, and deliver medicine exactly where it’s needed — all without surgery. It sounds like something from a science fiction movie. But this vision is rapidly becoming reality, thanks to a new breakthrough in magnetic soft robotics.
Researchers at North Carolina State University have developed an innovative 3D printing technique that creates paper-thin magnetic “muscles.” These thin films can be attached to origami-inspired robots, bringing them to life through movement — all powered by magnetism. The research, led by Dr. Xiaomeng Fang, an assistant professor in the Wilson College of Textiles, was recently published in Advanced Functional Materials.
The development represents a major leap in soft robotics, a field that focuses on building robots from flexible, lightweight materials. Unlike traditional robots made of metal and plastic, soft robots are made of rubber-like materials that can bend, stretch, and twist — mimicking the flexibility of living organisms.
But making these robots move has always been a challenge. Until now.
How the Technology Works
The key to this innovation lies in combining rubber-like elastomers with ferromagnetic particles — materials that respond strongly to magnetic fields. Using a specialized 3D printing process, Fang’s team infused these magnetic particles into an elastic polymer, creating a thin, flexible film that acts like an artificial muscle.
When exposed to an external magnetic field, the film contracts or bends, producing motion. These films — often just a fraction of a millimeter thick — can be attached to origami-inspired structures. As the magnetic field changes, the origami folds and unfolds in a controlled manner.
“In traditional designs, magnetic actuators use small rigid magnets — like the ones on your refrigerator,” explains Fang. “You attach these to the surface of a soft robot to make it move. But our method lets us print a magnetic layer directly onto the robot, so it barely takes up any space and doesn’t interfere with its movement.”
This is a game-changer for origami-based robotics, where every millimeter of space and flexibility counts.
The Magic of Origami in Robotics
Origami — the ancient Japanese art of paper folding — has become an unlikely hero in modern engineering. Scientists have long admired how simple folds can transform a flat sheet into complex 3D shapes. In robotics, these folding structures are incredibly useful because they can be compact, lightweight, and multifunctional.
The NC State researchers used a well-known folding pattern called Miura-Ori, which is especially good at compressing and expanding large surfaces. This pattern allows the robot to be small when folded — ideal for traveling through narrow spaces like inside the human body — and then expand into a larger shape when it needs to perform a task.
By attaching the paper-thin magnetic films to specific parts of the origami structure, the researchers effectively gave it muscles. When magnetic fields are applied, the muscles contract or expand, allowing the origami robot to fold, unfold, and move.
A Robot Designed to Heal from the Inside
One of the team’s first prototypes was a drug-delivery robot designed to treat ulcers inside the stomach. The concept is simple yet elegant.
Imagine swallowing a tiny capsule. Inside it is a folded origami robot coated with medicine. Once it reaches the stomach, doctors can use an external magnetic field to guide the robot to the ulcer site. When it’s in position, they trigger the magnetic films to unfold the robot, exposing its entire surface area to release the medication evenly.
The folding design allows the robot to be small enough to ingest yet large enough to deliver drugs effectively once deployed. This could make ulcer treatment — and many other internal therapies — safer, more precise, and completely noninvasive.
To test the idea, the researchers built a mock stomach using a plastic sphere filled with warm water, mimicking human body conditions. Using external magnets, they successfully navigated the robot through the model stomach, positioned it over a mock ulcer, unfolded it, and attached it in place using soft magnetic films. The result: controlled and steady drug release over time.
The potential here is enormous. Patients might one day receive targeted treatments without undergoing endoscopy or surgery. The robot could be designed to disintegrate naturally after completing its mission, leaving no trace behind.
Overcoming the Challenges of Magnetism
While the idea sounds simple, creating these magnetic “muscles” was far from easy. Previous researchers had tried mixing ferromagnetic particles into soft materials, but they faced a frustrating limitation: they couldn’t pack enough magnetic particles into the rubber to make it strong enough.
The problem lies in the 3D printing process itself. The material used to print these films needs to be cured — or solidified — using UV light. But when too many magnetic particles are added, the mixture becomes dark and absorbs the UV light, preventing proper curing.
Fang’s team solved this with a clever twist: they added a heated plate beneath the printing surface. The heat provided extra thermal energy, allowing the material to cure even when loaded with a high concentration of magnetic particles.
“Adding the hot plate meant we could use much more ferromagnetic material than before,” Fang explains. “And the more particles we can use, the stronger the magnetic force becomes. That was the real breakthrough.”
With this improvement, the team achieved a delicate balance: a flexible, ultrathin, and highly magnetic film that could perform like a muscle — strong enough to move origami robots but light enough not to interfere with their design.
The Crawling Origami Robot
The researchers didn’t stop at drug delivery. To demonstrate the versatility of their magnetic films, they built a second robot — this time, one that could crawl like an inchworm.
Using a different Miura-Ori pattern, they arranged the magnetic “muscles” at key points on the origami body. When exposed to a changing magnetic field, certain parts of the robot contracted while others relaxed. This caused the front part to lift and the back part to pull forward. When the magnetic field was turned off, the robot returned to its original shape, effectively pushing itself forward — one small “step” at a time.
Despite its tiny size, the crawling robot could climb over obstacles up to 7 millimeters high and move across uneven surfaces like sand. The speed and movement could be controlled by simply adjusting the strength and frequency of the magnetic field.
This crawling motion is significant because it opens doors to exploration and inspection in environments too dangerous or confined for humans or larger machines — like inside pipes, blood vessels, or even extraterrestrial terrains.
Tiny Robots, Huge Potential
Together, the drug-delivery robot and the crawling origami robot showcase what’s possible when magnetic actuation meets origami design.
“These examples are just the beginning,” says Fang. “There are many different types of origami structures that can be paired with these magnetic muscles. They could help solve problems in medicine, environmental monitoring, and even space exploration.”
Here are just a few of the potential applications scientists envision:
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Targeted Drug Delivery
Robots that can travel through the human body, unfold to release drugs, and then safely dissolve — offering precise treatments without surgery. -
Minimally Invasive Surgery
Origami-inspired devices that can be inserted through small incisions, expand to perform complex tasks, and fold back up for easy removal. -
Tissue Engineering and Healing
Magnetic films could help soft scaffolds expand or contract in ways that encourage tissue growth or assist in wound closure. -
Environmental Monitoring
Small robots that can navigate through tight underground spaces, soil, or underwater environments to collect samples or monitor pollutants. -
Space Exploration
Origami robots could be launched compactly in spacecraft and unfold upon arrival, performing repairs or collecting samples on other planets.
Why This Matters
At its core, this research represents more than a technical achievement — it’s a new way of thinking about machines.
Traditional robotics is based on rigid materials, motors, and electronics. But nature doesn’t work that way. Muscles, tendons, and organs are soft, flexible, and adaptive. By learning from biology, scientists are creating machines that can interact safely with humans and adapt to their environments.
Soft robots made from magnetic films can move without onboard batteries or motors, powered instead by external magnetic fields. This makes them safer for medical use, since there are no electrical parts that could heat up or malfunction inside the body.
Moreover, their small size and flexibility mean they can reach places traditional tools cannot. For instance, they might one day travel through blood vessels, remove blockages, or deliver therapies deep inside the body — all controlled by doctors from outside using magnetic fields.
The Road Ahead
Although these robots are still in the experimental stage, the results so far are promising. The next steps will focus on making them biocompatible (safe for living tissues), reliable, and scalable for mass production.
Researchers also plan to explore programmable magnetic responses, allowing the robots to perform multiple types of movement — not just folding or crawling, but perhaps even swimming or jumping.
Other challenges include developing ways to track the robots inside the body in real time and ensuring that their magnetic control is precise enough to perform delicate medical procedures.
Fang’s team is already collaborating with biomedical engineers to explore these possibilities. They’re also looking beyond medicine, envisioning applications in wearable technology, smart textiles, and adaptive materials that can change shape on demand.
A Future Folded in Innovation
The marriage of origami and robotics is one of the most creative frontiers in modern science. By blending art, engineering, and physics, researchers are unlocking new ways to make machines that are small, flexible, and intelligent.
The invention of paper-thin magnetic muscles adds a powerful new tool to this field. It brings us closer to a world where machines can move as gracefully as living organisms, fold themselves into new shapes, and perform tasks once thought impossible — from healing the human body to exploring distant worlds.
As Dr. Fang puts it:
“We’re only just beginning to understand what’s possible. These thin magnetic muscles can work with so many origami structures — the potential is limitless. It’s going to be exciting to see how far we can take this technology.”
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