Introduction
The application of mini-robots in medicine has been an area of growing interest and innovation. From targeted drug delivery to performing delicate surgical procedures, the list of possibilities is extensive. An arsenal of robots ranging in size from nanometers to centimeters has already been developed and tested for a variety of medical tasks.
Challenges of Mini-Robots in Medicine
Despite advances, the mini-robots available today face significant limitations. In endoscopic microsurgery procedures, for example, the necessary instruments are often too heavy for a single, millimeter-sized robot to transport them to their desired destination. Furthermore, the locomotion of these robots is hampered by the presence of mucus on the internal surfaces of the body, reducing grip and causing slipping.
TrainBot Innovation
To overcome these challenges, a team led by Tian Qiu at the German Cancer Research Center (DKFZ) in Dresden developed an innovative solution: the TrainBot, a convoy connecting several millimeter-scale mini-robots. Equipped with enhanced, non-slip, spike-like feet, these robots work together to transport endoscopic instruments.
TrainBot operates wirelessly, controlled by a rotating magnetic field that simultaneously coordinates the individual units. This approach allows for precise movements in a single plane, controlling both direction and rotation—essential for maneuvering in confined spaces within the human body. The external actuation and control system is designed to operate at distances compatible with the scale of the human body.
Application in Bile Duct Microsurgery
Researchers at the DKFZ in Dresden have already used their three-unit TrainBot convoy to simulate a surgical procedure. In the case of bile duct cancer, the duct often becomes blocked, causing a dangerous buildup of bile. The obstruction must be opened after an endoscopic diagnosis, which involves navigating a sharp angle through the small intestine to the bile duct—a significant challenge for flexible endoscopes.
"This is where the flexible robotic train can show its strengths," says project leader Tian Qiu. His team demonstrated this using organs removed from a pig. The robot train was able to maneuver an endoscopic instrument equipped with a wire electrode for electrical ablation of tissue in the bile duct. Once the electrode tip reaches the site, an electrical voltage is applied, and the tissue obstruction is gradually removed through a process known as "electrocautery." The wire electrode used was 25 cm long and three and a half times heavier than a TrainBot unit.
Future perspectives
"After the promising results with TrainBots in the organ model, we are optimistic about developing mini-robot teams for other tasks in endoscopic surgery," says Moonkwang Jeong, first author of the study. The possibility of using mini-robot trains opens new frontiers in minimally invasive medicine. In addition to removing obstructions, these robots can be programmed to deliver catheters for fluid drainage or administer medications directly to the affected site.
This advancement represents a significant step toward the next generation of medical procedures, where technology and innovation work together to improve patient outcomes and expand the boundaries of what's possible in modern medicine. Collaboration between robotic units amplifies individual capabilities, offering efficient solutions to challenges previously considered insurmountable.
