A group of USA researchers has created what they say are the first-ever living robots, which were made of frog embryos' cells and can be programmed for a specific job, according to their study published by the U.S. journal Proceedings of the National Academy of Sciences.
Such tiny robots could "heal" themselves when damaged, avoiding the need for hard maintenance and fix, and when they've completed their job they can simply break down organically.
These millimeter-wide "xenobots" were designed on a supercomputer using an evolutionary algorithm to create thousands of candidate designs.
They found that the skin cells formed a more passive architecture, while the once-random contractions of heart muscle cells were put to work creating ordered forward motion, allowing the robots to move on their own. They then transferred the computer designs into life.
The xenobots are constructed using stem cells harvested from the embryos of African frogs, the species Xenopus laevis, and could theoretically perform tasks ranging from highly-targeted medicine delivery inside the human body, to toxic waste clean-up after a spill or radioactive disaster, or even gathering microplastics floating in the Earth's oceans.
Later tests showed that groups of xenobots would move around in circles, pushing pellets into a central location - spontaneously and collectively. The heart cells have enough energy to keep swimming for 7-10 days. It's a new class of artifact: "a living, programmable organism", Bongard pointed out.
"You look at the cells we've been building our xenobots with, and, genomically, they're frogs", said co-leader Michael Levin, from Tufts University.
While the frog-bots are still at a very early stage in development, it's possible that more complex versions could be used in the future for tasks like nano-surgery (performing jobs such as cleaning plaque from arteries or delivering drugs) and cleaning up micro-plastics.