A swarm of tiny, shape-changing, all-metal robots might someday deliver drugs and capture biopsy samples painlessly and then safely dissolve without the need for extraction, according to a study to be presented today at Digestive Disease Week® (DDW) 2026 .
These first-of-their-kind microrobots combined durability and safety in testing on mice, said study co-lead author Ling Li, MD, instructor, gastroenterology and hepatology at Johns Hopkins University School of Medicine.
"Existing biodegradable microrobots are made of materials such as polymers or hydrogels that biodegrade, but they lack the strength and rigidity that enable our all-metal microrobots to penetrate and cut tissue, while still leaving no trace behind when their work is done," Dr. Li said.
Using microrobots may someday replace some conventional, uncomfortable, invasive endoscopy procedures by simply swallowing a capsule. Thousands of the devices packed into a capsule could journey into the body, where, like tiny transformers, the pre-programmed microrobots shift their shapes at their destination to form minuscule grippers to collect tissue samples in areas difficult to reach using traditional methods.
They can also transform into microinjectors to deliver medications, serving as an alternative to injection or intravenous infusion for delivering biologics such as anti-tumor necrosis factor (TNF) agents and glucagon-like peptide-1 (GLP-1) medications. By injecting them under the mucosal lining of the gastrointestinal tract and by targeting particular locations in the body rather than distributing medication broadly, this approach could improve how medications are absorbed. It also could eliminate the need for frequent injections or clinic visits for treatment of gastrointestinal conditions such as inflammatory bowel disease, bleeding and cancer.
By altering the thickness of the metal layers, the research team can control the tension between layers and how they fold to form two-dimensional and three-dimensional shapes.
"The variability of the layers' thickness and use of other materials determines how long the metals last before they begin to biodegrade," said co-lead author Wangqu Liu, PhD candidate at Johns Hopkins University Whiting School of Engineering, who designed and fabricated the microrobots. "We can control the degradation rate from minutes to months depending on the application."
The researchers demonstrated their microrobots' ability to penetrate the inner lining of the intestine for potential drug delivery in the gastrointestinal tracts of mice. They also showed the devices' ability to morph as programmed and insert their tips into the layer of tissue just beneath the surface of the intestine without punching holes or causing other damage.
The research team developed a novel liquid-free manufacturing process that enabled them to create a new class of stronger microrobots composed of water-soluble metals and metal oxides, which give them their biodegradable properties. The process uses only a tiny amount of metal.
"It's typically only a few micrograms, and it's engineered to stay within established safety limits," Liu said.
"We see these all-metal, biodegradable devices as an important advancement in the effort to realize the full potential of medical microrobots," Dr. Li said. "We don't have to choose between strength and safety. We can have both."
The researchers acknowledge the Gracias laboratory at the Johns Hopkins University Whiting School of Engineering for microrobot design and fabrication, and the Selaru laboratory at the Division of Gastroenterology and Hepatology of Johns Hopkins School of Medicine for animal testing and clinical applications for this work.
DDW Presentation Details
