image: (a) In nature, small fish can swim agilely and increase their survival probabilities by forming schools that dynamically aggregate and disperse for collective foraging. (b) Inspired by nature, a miniature fish-like magnetic soft robot composed of hard-magnetic elastomers has been developed. Under the actuation of an oscillating magnetic field and with the assistance of a gradient magnetic field, the robotic individuals can achieve fish-like swimming with constrained 6 DOFs. (c) Based on the mechanism where the constant component of an oscillating magnetic field at natural frequency uniquely dominates the swimming direction of fish-like magnetic soft robots, by programming the spatial distribution pattern of the constant component, the swiming direction of individual robots can be differentially regulated, inducing swarm behaviors. Robotic swarms can 3D disperse and aggregrate like migrating fish schools, achieve obstacle avoidance, and enrich toward the lesion. Upon reaching the lesion interface, the robot swarm can then adjust its morphology and position on the solid-liquid interface, similar to fish foraging, adapting to the lesion boundary for better adhesion.
Credit: ©Science China Press
Scientists at Harbin Institute of Technology have achieved a major breakthrough in medical robotics by creating swarms of fish-like miniature robots that can navigate through the human body to deliver targeted drug therapy. The research, published recently, demonstrates how these tiny magnetic soft robots can work together like fish schools to overcome the limitations of individual minature soft robots in medical applications.
The swarm of robots, each measuring just 2 millimeters in length, are inspired by the natural migration and foraging behaviors of fish. Unlike previous miniatue soft robots that operate independently, these devices can coordinate their movements as a unified swarm, allowing them to cover larger areas and deliver more effective doses of medication to diseased tissue.
The key innovation lies in the robots’ ability to respond to programmed magnetic fields. When the magnetic field frequency approaches the robots’ natural resonance, their swimming direction becomes controlled entirely by one constant component of the magnetic field, enabling researchers to guide different robots in different directions simultaneously. This breakthrough allows for true swarm coordination under a single global magnetic field control system.
Each individual robot possesses six degrees of freedom movement, including the ability to pitch, yaw, roll, translate horizontally and vertically, and swim forward at speeds comparable to fish. The robotic swarm can disperse to navigate through narrow passages in the body, then aggregate at target locations such as lesions or tumors. Once they reach their destination, the swarm can adapt its shape to match the contour of the diseased tissue for optimal drug delivery coverage.
The research team demonstrated the technology’s potential through extensive laboratory experiments and ex vivo testing using animal tissue samples. In one experiment, the robot swarm successfully navigated to a simulated gastric lesion, aggregated at the site, and adjusted their collective morphology to conform to the lesion's boundaries for targeted drug delivery.
This research was supported by multiple funding sources, including the National Key Research and Development Program of China, National Natural Science Foundation of China and Natural Science Foundation of Heilongjiang Province of China.