We've been hearing a lot lately about micro-robots, that could one day perform tasks such as capturing pollutants from the environment. Scientists have now created a sturdy batch of such bots, that heal back together when cut in two.
Most "microbots" developed so far have been made of materials such as soft hydrogels or hard polymers. Although these substances may stand up to applications such as targeted drug delivery within the human body, they could tear or snap when subjected to harsh mechanical stress in the outside world.
Prof. Joseph Wang, along with his colleagues at the University of California-San Diego, designed the experimental new self-healing robots with that limitation in mind. Each fish-shaped unit is 2 cm long (0.8 in) and consists of a layer of conductive material on the bottom, a layer of stiff hydrophobic (water-repelling) material in the middle, a top strip of aligned magnetic microparticles, and a platinum tail.
When one of the robots is placed in a weak hydrogen peroxide solution, the platinum reacts with that chemical, producing oxygen bubbles which propel the bot forward. If the robot is cut in half, the tail end will continue to swim on its own, circling around until it collides with the front end. Magnetic attraction then pulls the two halves together, joining them back into one.
In tests performed in petri dishes, the robots were even able to reform themselves after being cut into three pieces – the swimming tail first joined up with one piece, and then the two of them proceeded to merge with the other piece.
The self-healing microbots are described in a paper that was recently published in the journal Nano Letters, and can be seen in action in the video below.
Source: American Chemical Society
