The Korea Advanced Institute of Science and Technology (KAIST) announced the development of a self-propelled, biocompatible cell robot powered by urea—a natural biological byproduct—without the need for external power sources or complex mechanical systems. Professor Insung Choi led the research from the Department of Chemistry.
The newly developed platform enables autonomous, directional movement and can be adapted for various functions, including targeted material transport and environmental modulation.
The team focused on yeast as the base organism, citing its stability, availability, and ability to generate ethanol—a potentially usable byproduct—during glucose metabolism. This approach allows the system to operate using substances the organism naturally produces, without requiring artificial or external devices.
During the metabolic breakdown of glucose, yeast generates ethanol. The team used this ethanol to activate a nanoscale, biocompatible shell on the yeast’s surface. To construct this system, they introduced a two-enzyme mechanism comprising alcohol oxidase (AOx) and horseradish peroxidase (HRP), which triggers a chain of enzymatic reactions that ultimately form a melanin-based nanoshell around the yeast cell.
To induce motion, the researchers attached urease—an enzyme that breaks down urea into ammonia and carbon dioxide—to the nanoshell. The resulting chemical reaction produced the propulsion necessary for the robot’s autonomous movement. The team confirmed that the cell robot’s asymmetrical structure enabled a clear directional thrust.
According to the researchers, this self-propelled system operates using only materials naturally present in its surroundings. It does not require magnets, lasers, or other external control systems, making it both simpler and more biocompatible. Additionally, the nanoshell surface can be chemically modified to carry a variety of enzymes, allowing the cell robot to utilize different biological fuels for expanded functionality.
Nayoung Kim, a PhD candidate in the Department of Chemistry and first author of the study, noted the platform’s future potential. She described the self-propelled cell robot as a new class of responsive systems capable of autonomous motion and environmental sensing. According to Kim, this technology has the potential to make significant contributions to targeted cancer therapies and precision drug delivery.
The research findings were published in the journal Science Advances.