Researchers at École polytechnique fédérale de Lausanne (EPFL) and Swiss Federal Institute of Technology in Zurich have developed a technique for building “mobile micromachines” inspired by origami that can be controlled and powered remotely using magnets. The goal is to eventually use the technology to create diagnostic and therapeutic devices that can travel through the body and perform specific actions, reaching areas and doing tasks that are difficult with existing techniques.
The investigators’ approach allows for a wide variety of tiny robots that change shapes in different ways and respond to magnets uniquely based on their proportions.
EPFL explains the construction of the microrobots:
First, the nanoparticles are placed inside layers of a biocompatible hydrogel. Then an electromagnetic field is applied to orientate the nanoparticles at different parts of the robot, followed by a polymerization step to “solidify” the hydrogel. After this, the robot is placed in water where it folds in specific ways depending on the orientation of the nanoparticles inside the gel, to form the final overall 3D architecture of the microrobot.
Once the final shape is achieved, an electromagnetic field is used to make the robot swim. Then, when heated, the robot changes shape and “unfolds”. This fabrication approach allowed the researchers to build microrobots that mimic the bacterium that causes African trypanosomiasis, otherwise known as sleeping sickness.