Scientists who created the first living robots have revealed that the organisms, known as xenobots, can now reproduce, according to their study.
Created using stem cells from the African Clawed Frog (Xenopus laevis), xenobots are less than one millimetre wide and can move, work together as a group and even self-heal.
But now, the scientists who developed them have found they can reproduce in an entirely new way – completely different from the biological reproduction of any living plant or animal.
“I was astounded by it,” professor of biology and director of the Allen Discovery Center at Tufts University, Michael Levin said, as reported by CNN.
This new form of reproduction sees the xenobots effectively harvest loose stem cells, gathering them together into piles which can then mature into xenobots.
“Frogs have a way of reproducing that they normally use,” Levin said. “But when you ... liberate [the cells] from the rest of the embryo and you give them a chance to figure out how to be in a new environment, not only do they figure out a new way to move, but they also figure out apparently a new way to reproduce.”
However, they soon discovered that replication happened rarely with the original, spherical-shaped xenobots. And only under specific circumstances. The bots used a process known as kinetic replication – known to occur at a molecular level but never seen on this scale, using entire cells or organisms.
After realising the xenobots shape was hindering them, researchers used AI to test a variety of new body shapes to maximise the stem cell harvesting process. The AI settled on a C-shape which resembles iconic gaming character, Pac-Man.
“The AI didn't program these machines in the way we usually think about writing code. It shaped and sculpted and came up with this Pac-Man shape,” lead author of the study, Josh Bongard said – a computer science professor and robotics expert at the University of Vermont. “The shape is, in essence, the program. The shape influences how the xenobots behave to amplify this incredibly surprising process.”
Stem cells are often used in medicine to replace damaged cells or to fight certain forms of cancer and blood-related diseases. However, their use as biological robots involved merely harvesting the cells from frog embryos and leaving them to incubate.
“Most people think of robots as made of metals and ceramics,” Bongard said. “But it's not so much what a robot is made from but what it does, which is act on its own on behalf of people.”
“In that way it's a robot,” he added. “But it's also clearly an organism made from genetically unmodified frog cell.”
Although the thought of self-replicating machines is reminiscent of the likes of The Terminator and Terminator 2: Judgment Day, the researchers are assured that these robots are contained in a lab and are both biodegradable and are easily extinguished.
But the discovery of self-replicating robots opens up a whole new world of possibilities. A bit more useful than Elon Musk's proposed humanoid robots.
“There are many things that are possible if we take advantage of this kind of plasticity and ability of cells to solve problems,” Bongard said.
The study was originally published in the peer-reviewed scientific journal PNAS on November 20, 2021.
Main image credit: Douglas Blackiston & Sam Kriegman in the research article.
Ryan Leston is an entertainment journalist and film critic for IGN. You can follow him on Twitter.
