Team creates shape-shifting medical microbots

The protozoan Trypanosoma brucei causes African sleeping sickness and the disease was so prevalent at one point, it made parts of Africa uninhabitable.

But now, the microorganism is serving as a model for Swiss-based engineers developing a new class of microscopic robots that could be used to deliver drugs or perform life-saving surgeries at a microscopic scale.

According to a new report in the journal Nature Communications, engineers at the Ecole Polytechnique Federale Lausanne (EPFL) and the Eidgenössische Technische Hochschule Zürich (ETHZ) in Switzerland are creating and assessing various designs of microscopic robots that can not only move around, but can be generated rapidly using a new manufacturing process. The outcome is a microscopic robot that can be manipulated with an electromagnetic field and, when warmed up, can even change its shape.

Designs Inspired by Bacteria

To make the robots, the team is using biocompatible hydrogel and magnetic nanoparticles, with the latter allowing the drones to move via magnetic field manipulation.

The researchers said they were inspired by Trypanosoma brucei, particularly its flagellum that it uses to move from the Tsetse fly to its host’s bloodstream. Once inside the host, the protozoan hides the whip-like appendage as a survival mechanism.

The new class of micro-drones uses an artificial flagellum to maneuver to a destination. Then, a laser can be used to change configuration and wrap the appendage around the robot, getting it out of the way.


Credit: EPFL

The microbot is created by putting tiers of magnetic nanoparticles into a biocompatible hydrogel. An electromagnetic field then moves the nanoparticles to various parts of robots and the hydrogel is hardened to keep it all in place. When put into water the micro-drone folds according to the orientation of the nanoparticles to create the last arrangement.

“We show that both a bacterium’s body and its flagellum play an important role in its movement,” study author Selman Sakar, a robotics engineer at EPFL, said in a news release. “Our new production method lets us test an array of shapes and combinations to obtain the best motion capability for a given task. Our research also provides valuable insight into how bacteria move inside the human body and adapt to changes in their microenvironment.”


Image credit: EPFL