Morphing microrobots change shape according to environment

Researchers in Switzerland have developed a new breed of microrobots that alter their shape automatically to navigate different environments, with potential for medical applications.

(Credit: EPFL/ETHZ)

Inspired by bacteria, the tiny robots are made from hydrogel composites and contain magnetic nanoparticles that would allow them to be directed from outside the human body. While this method of external control is not new, novelty can be found in the way the robots manipulate their shape autonomously in response to their surroundings. Changes in viscosity, for example, prompt the microrobots to morph into more efficient shapes to maintain momentum. Led by engineers from ETH Zurich and its sister institution École polytechnique fédérale de Lausanne (EPFL), the research is published in Science Advances.

“Our robots have a special composition and structure that allow them to adapt to the characteristics of the fluid they are moving through,” said Mahmut Selman, an assistant professor at EPFL’s Institute of Mechanical Engineering.

“For instance, if they encounter a change in viscosity or osmotic concentration, they modify their shape to maintain their speed and manoeuvrability without losing control of the direction of motion.”

This ‘adaptive locomotion’ can be programmed using an origami-based folding technique. As the tiny devices are able to swim through fluids and modify their shape when needed, they can pass through narrow blood vessels and intricate systems with no loss of speed or flexibility. The researchers conducted a number of tests that demonstrated the microrobots adapting to different physical and chemical environments, shifting from a paddling gait to helical momentum. According to the team, this flexibility could enable the devices to target areas of the body that are traditionally hard to reach, opening up new method for more localised treatment of diseases.