Smart Micro Robots Are Coming

Researchers at Paul Scherrer Institute PSI and ETH Zurich have developed a micromachine capable of performing different actions. First, nanomagnets found in the components of micro robots are programmed magnetically, and then various movements are controlled by magnetic fields. These machines, measuring only a few micrometers in size, can be used to perform small procedures in the human body. Researchers published their results in the scientific journal Nature. The robot, measuring only a few micrometers, resembles a paper bird made using Japanese paper-folding art origami. However, unlike a paper structure, the robot can move as if by magic, without visible force. It flaps its wings or bends its neck and retracts its head, all of these actions made possible by magnetism. Researchers at Paul Scherrer Institute PSI and ETH Zurich built the micromachine using materials containing small nanomagnets. These nanomagnets can be programmed to assume a specific magnetic orientation. When the programmed nanomagnets are then exposed to a magnetic field, specific forces act upon them. If these magnets are placed in flexible components, the forces acting upon them enable the components to move.

Scanning electron microscope image showing the arrangement of nano-scale magnets in a structure similar to a bird. The magnets can be magnetized in different directions parallel to the color bars. By programming their magnetization, researchers enable the bird to perform different movements in a magnetic field. (Photo: Paul Scherrer Institute / Swiss Federal Institute of Technology, Zurich)

 

Programming Nanomagnets

Nanomagnets can be programmed repeatedly. This reprogramming results in different forces and enables new movements. For the construction of the microbot, researchers fabricated cobalt magnet arrays on thin silicon nitride layers. Bird-shaped microbots built from this material can subsequently perform various movements such as wing flapping, hanging, rotating, or lateral sliding. Laura Heyderman, Head of the Multiscale Materials Experiments Laboratory at PSI and Professor of Mesoscopic Systems at ETH Zurich, says, "The movements made by the microrobot occur within milliseconds. However, the programming of nanomagnets takes only a few nanoseconds. This makes it possible to program different movements in succession. This demonstrates that the small microbird can first flap its wings, then move sideways, and then flap its wings again. When needed, the bird can also remain stationary," says Heyderman.

Intelligent Micro Robots

This new concept represents an important step toward micro and nanorobots that not only store information for performing a specific action but can also be reprogrammed to perform different tasks. Bradley Nelson, Head of the Department of Mechanical and Process Engineering at ETH Zurich, said, "In the future, one could imagine an autonomous micromachine circulating in human blood vessels and performing biomedical tasks such as killing cancer cells." Tianyun Huang, a researcher from the Institute of Robotics and Intelligent Systems at ETH Zurich, said, "Other application areas can also be considered, such as flexible microelectronics or microlenses with the ability to change optical properties." Additionally, applications where surface properties change are also possible. Jizhai Cui, an engineer and researcher working at the Mesoscopic Systems Lab, states, "For example, it could be used to create surfaces that can be wetted by water or repel water."