Researchers at Ecole polytechnique fédérale de Lausanne and ETH Zurich in Switzerland have developed tiny robots that could pave the way for advanced drug delivery. Inspired by bacteria, the microrobots can swim through fluids and modify their shape so as to pass through narrow blood vessels or intricate structures. The researchers hope that the devices could be useful in delivering drug cargoes to target tissues in the body.
Developing a microrobot that can successfully navigate vasculature is a significant challenge, with narrow, winding blood vessels providing plenty of places for a robot to get stuck. To address this, the Swiss researchers turned to nature and an origami-based folding technique.
“Nature has evolved a multitude of microorganisms that change shape as their environmental conditions change,” said Bradley Nelson, a researcher involved in the study. “This basic principle inspired our microrobot design. The key challenge for us was to develop the physics that describe the types of changes we were interested in, and then to integrate this with new fabrication technologies.”
The research team made their microrobots using a hydrogel nanocomposite that contains magnetic nanoparticles, meaning that they can control the robots using an electromagnetic field. The robots can either travel around the body under the influence of the external magnetic field, which could be useful in getting them to accumulate near a target tissue, or they can be propelled by the bloodstream.
However, the key to the robots’ ability to navigate through tight spaces lies in deformations the researchers introduced into their structure. These deformations allow the microrobots to automatically assume the most efficient shape when navigating a particular obstacle.
“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, another researcher involved in the study. “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.”
See a video of the robots in action below:
Study in Science Advances: Adaptive locomotion of artificial microswimmers…