Tiny microbots fold like origami to travel through the human body

Tiny robots modeled after bacteria could be used to deliver drugs to hard to reach areas of the human body. Scientists at École polytechnique fédérale de Lausanne (EPFL) and the Swiss Federal Institute of Technology in Zurich (ETH Zurich) have developed what they call elastic microbots that can change shape depending on their environment.

When a patient needs medication, traditionally it is given orally or intravenously and the body’s systems will carry the medicine to the part of the body where it is needed. But recent developments in the field of targeted drug delivery have helped to ensure that medication is delivered to the specific area where it is required, with a higher concentration of the medication in some places. The development of elastic robots could potentially revolutionize targeted drug delivery by making it possible to deliver medication to any area of the body, even those that are difficult to access.

The microbots are highly flexible and are able to swim through fluids and change their shape in response to their environment, meaning they can squeeze through narrow blood vessels without slowing down or being difficult to maneuver. The bots are made of minute hydrogel nanocomposites which contain magnetic nanoparticles, so they can be controlled through the use of an electromagnetic field.

After creating the robots, the challenge was to find a way to “program” their shapes so that they could pass through all the different environments of a human body. Scientists found a way to use embodied intelligence, in which the bot’s physical being is adaptive to surroundings, rather than the traditional computation that most electronic systems use. The bots are constructed with an origami-based folding method which allows them to deform to the most efficient shape for any given environment, and deformations can be set in advance to make performance smoother. Once inside a body, the robots can either be controlled by an electromagnetic field or they can be left to make their own way by using the fluid flow inside the body.

“Our robots have a special composition and structure that allow them to adapt to the characteristics of the fluid they are moving through,” said Selman Sakar,  Assistant Professor, Institute of Mechanical Engineering, EPFL, in a statement. “For instance, if they encounter a change in viscosity or osmotic concentration, they modify their shape to maintain their speed and maneuverability without losing control of the direction of motion.”

The findings are published in Science Advances.