In a breakthrough that can reshape the treatment of internal injuries, scientists have created a swallowable printer that can print living tissue in the body to mend damaged tissue—no surgery required. The gadget, dubbed the Magnetic Endoluminal Deposition System, or MEDS, may one day cure ulcers, bleeding, or internal wounds by taking a pill.
Designed at EPFL’s School of Engineering, MEDS is a fusion of two rapidly developing fields: bioprinting, where bio-inks are used to print tissue scaffolds, and smart capsules that release medication or monitor biological reactions in the body.
The result is a device that can navigate along the digestive system, target specific points, and dispense biocompatible ink onto internal injuries while being operated by magnets from the outside.
MEDS: size comparison. (CREDIT: 2025 LAFT EPFL CC BY SA) A Small Printer with a Large Task
Capsule-sized, MEDS is about the width of a giant vitamin tablet. Inside, a spring-loaded plunger houses an infinitesimal bio-ink chamber comprised of soft, biocompatible gels resembling natural seaweed polymers.
Upon exposure to a near-infrared laser beaming outside onto the capsule, it heats a shape-memory polymer that expels the plunger. This movement forces the bio-ink out through the tip of the capsule, much in the way one pushes a pen onto paper—except this “pen” is writing on human tissue.
In order to steer it, the capsule carries a small magnet on board, and the doctors employ a second magnet on a robotic arm outside the patient’s body as a sort of remote control. Physicians can maneuver the capsule by moving the external magnet, which propels the capsule along in soft contact with tissue surfaces rather than floating randomly through fluid. The technique allows for precise printing even in the serpentine, fluid-filled passageways of the digestive tract.
From Lab Tests to Living Probes
The scientists first tested MEDS in laboratory models of the stomach, where it was used to print bio-ink on simulated ulcers and bleeding wounds. In controlled settings, the capsule released ink in smooth lines and successfully sealed a simulated hemorrhage at a flow rate of five milliliters per minute. The flow nearly stopped once the ink had solidified, with potential for use in sealing actual wounds.
MEDS: the external actuator magnet. (CREDIT: 2025 LAFT EPFL CC BY SA)
To achieve better printing accuracy, the researchers experimentally tested different geometries of the nozzles. They found that a four-barbed ejector tip allowed the capsule to print cleaner, more precise lines of bio-ink than other geometries. Preprogrammed path navigation experiments within silicone models that mimic the loops and curves of the stomach showed the capsule to be able to follow predictably.
With these positive bench tests completed, the team conducted animal testing in anesthetized rabbits. Guided by magnetic fields and tracked with X-ray fluoroscopy, MEDS traveled through the stomach, deposited bio-ink onto the stomach lining, and was then safely retrieved from the mouth. Although these procedures did not measure tissue healing, they confirmed the ability of the technology to navigate, print, and be retrieved all without open surgery.
What Sets MEDS Apart
Whereas the majority of traditional medical devices contain onboard electronics and wires, MEDS contains none. Everything that drives and guides it stays outside the body. This kind of design makes it easy and safer to operate inside the body. The system offers complete control over rotation—yaw, pitch, and roll—so that the capsule can print in any orientation.
The bio-ink used in those experiments had a structural integrity of more than two weeks in laboratory settings, long enough to serve as a “micro-bioreactor.” That would mean the printed item would have the capacity to encapsulate cells or release growth factors to trigger natural healing.
“By combining the principles of in-situ bioprinting with smart capsule design, we’re envisioning a new class of medical device—a swallowable bioprinter,” says Vivek Subramanian, head of EPFL’s Laboratory for Advanced Fabrication Technologies.
Overview of MEDS (Magnetic Endoluminal Deposition System) and its capabilities. (CREDIT: Advanced Science)
Sanjay Manoharan, a PhD candidate, also says that the bio-ink retained its form for over 16 days, which could mean it may attract cells and release healing agents. “The findings show great potential,” he reports. “We plan to apply MEDS to blood vessels and the peritoneum next.”
Overcoming Challenges Ahead
As great as it is, MEDS will still face a number of challenges before it can be used by humans. Being propelled by an external magnet, the ability of the capsule is limited to the relative proximity to the surface of the body. Future designs can use stronger magnetic arrays to operate deeper in the body.
The system’s natural movements also pose challenges. Rhythmic peristalsis contractions, which propel the food forward, could disturb the course of the capsule or get in the way of printing accuracy. Researchers see using sensors and smart algorithms to allow the device to self-correct automatically in real time.
The hostile conditions in the stomach are a problem to be overcome. Acid and constant motion can result in dislodgment or destruction of the printed bio-ink before it can carry out its function. To deal with this, later bio-inks can have cell adhesion peptides or enzyme-activated materials that stick to tissue better and resist erosion better.
Finally, manual operation is still in place for the current control system of the capsule. Computer-controlled systems to move around and print will be required for application in real-world situations in hospitals.
The Promise of Noninvasive Healing
If developed, the technology might change the way internal injuries are dealt with. Rather than be operated on to fix ulcers, perforations, or tiny internal bleeds, patients might one day swallow a pill that carries the desired location of damage and prints a tailored tissue patch in situ.
This technique could cut the risk of infection, shorten hospital stays, and lower costs. Because the capsule may be retrieved from the mouth, no surgical cuts or anesthesia are required. Beyond the digestive tract, such systems could possibly treat damage in the lungs, bladder, or blood vessels.
The concept revolutionizes medicine from passive treatment—prescribing patients pills that suppress symptoms—to active reconstruction, with devices really repairing tissue from the inside out. “It’s like sending a small repair crew inside the body,” described one scientist, describing MEDS as a leap from conventional pill therapies to something more dynamic and restorative.
Practical Implications of the Research
The MEDS work presents a new generation of noninvasive surgery and regenerative medicine. Polished, the technology would have the potential to equip doctors with the ability to heal damage within the body by swallowing it, rather than through surgery. Patients would enjoy quicker recovery time, fewer opportunities for complications, and reduced hospital stays.
In the future, the swallowable bioprinter idea might be used much, much more than treating stomach ulcers. These capsules might one day be able to dispense living cells, create tissue scaffolds for organ repair, or even repair damaged small blood vessels. The technology can be employed for controlled medicine release or as a diagnostic tool that prints biosensors directly in the body.
With growing automation and biological confirmation, MEDS could redefine “minimally invasive” medicine to make repairing tissue as simple as taking a pill.
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