Scientists in Switzerland have developed a technique for speeding-up the production of remote controlled, bio-inspired microrobots that can be used to treat patients in place of a medical operation.

The miniature robots are designed to enter the human body to either deliver drugs at specific locations or perform precise operations like clearing clogged-up arteries. They optimize medicine by replacing invasive, often complicated surgery.

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Selman Sakar of the Ecole Polytechnique Fédérale de Lausanne (EPFL) together with Hen-Wei Huang and Bradley Nelson at the Swiss Federal Institute of Technology in Zurich (ETHZ) developed a simple and versatile method for building bio-inspired robots and equipping them with advanced features.

They also created a platform for testing several robot designs and studying different modes of locomotion. Their work produced complex reconfigurable microrobots that can be manufactured with high throughput. The microrobots are still in development, however.

Researchers also built an integrated manipulation platform that can remotely control the robots' mobility with electromagnetic fields, and cause them to shape-shift using heat.

These soft, flexible and motorless microrobots are made of a biocompatible hydrogel and magnetic nanoparticles. The nanoparticles give the microrobots their shape during the manufacturing process, and make them move and swim when an electromagnetic field is applied.

To build the microrobots, nanoparticles are placed inside layers of a biocompatible hydrogel. An electromagnetic field is then applied to orient 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. When heated, the robot changes shape and "unfolds."

This fabrication approach allowed the researchers to build microrobots that mimic the bacterium that causes sleeping sickness. This particular bacterium uses a flagellum for propulsion, but hides it once inside a person's bloodstream as a survival mechanism.

The researchers tested different microrobot designs to come up with one that imitates this behavior. The prototype robot presented in this work has a bacterium-like flagellum that enables it to swim. When heated with a laser, the flagellum wraps around the robot's body and is "hidden."

"Our new production method lets us test an array of shapes and combinations to obtain the best motion capability for a given task," said Sakar.

"Our research also provides valuable insight into how bacteria move inside the human body and adapt to changes in their microenvironment."

Tagsmicrorobots, Switzerland, Ecole Polytechnique Fédérale de Lausanne, Swiss Federal Institute of Technology