New intracorporeal millirobot

Although the most common robots are those that work in factories or those that sweep and vacuum floors, it is possible that in the near future an important part of their prominence will be stolen by much smaller robots. These robots, called “milli-robots”, are usually no larger than a centimeter and it is hoped that one day they will be able to administer drugs in a very localized way inside the human body or perform minimally invasive surgeries. Now, researchers have developed a soft, biodegradable, magnetic milli-robot whose locomotion is inspired by the way certain insects walk and grab objects.

Some microsoft robots are already being developed for various biomedical applications, thanks to their small size and their ability to receive external power, often through a magnetic field. Their peculiar structures allow them to move inside the human body, for example through the rough tissues of our gastrointestinal tract. One day they might even be drugged and deliver the medicine needed to the exact spot in the body required. However, most of the milli-robots currently being worked on are made from non-degradable materials, such as silicone, meaning they would have to be surgically removed if used in clinical applications. In addition, these materials are not as flexible as desired and do not allow much adjustment of the robot’s properties, which limits its adaptability.

Bearing all these limitations in mind, a team including Liu Yang and Yajing Shen, from the City University of Hong Kong in China, among others, set out to create a milli-robot from soft, biodegradable materials that could roll, climb and grab objects, but easily dissolve once its work is done.

And it seems they have succeeded. His first achievement, although for now it is only a test model to test the design, is a millirobot made with a gelatin solution mixed with microparticles of iron oxide. By placing the material on a permanent magnet, the microparticles in the solution push the gel out, forming insect-like “legs” along the magnetic field lines.

As the iron oxide microparticles form magnetic chains within the gel, bringing a magnet close to the hydrogel bends the legs and produces a claw-like grasping motion.

In the experiments, the robot grabbed a 3D-printed cylinder and a rubber band and carried each one to other places.

The magnetic squishy milli-robot can bend, roll and grab things with its caterpillar-inspired legs. (Photo: City University of Hong Kong / American Chemical Society)

In addition, the researchers tested the ability of the millirobot to deliver a drug. Stocked with a dye, when the robot reached its destination, it unfolded and released the dye. To do this, the strategic use of magnets was enough.

The millirobot easily degraded in the water within two days, leaving only the tiny magnetic particles behind.

The researchers believe the new millirobot will be useful for intracorporeal drug delivery and other biomedical applications.

The team exposes the technical details of their milli-robot in the academic journal ACS Applied Polymer Materials, under the title “Soft Tunable Gelatin Robot with Insect-like Claw for Grasping, Transportation, and Delivery”. (Font: NCYT by Amazings)