The American scientists who created the first ‘living’ robots say the life forms, known as xenobots, they can now reproduce – and in a way not seen in plants and animals.
Formed from the stem cells of an African frog species (Xenopus laevis), from which it takes its name, the xenobots they are less than a millimeter wide. The tiny blisters were first revealed in 2020, after experiments showed they could move, work together in groups, and heal themselves.
Now, the scientists who developed them at the University of Vermont, Tufts University and the Wyss Institute for Biologically Inspired Engineering at Harvard University say they have discovered an entirely new form of biological reproduction, unlike any animal or plant known to science.
“I was surprised by that,” said Michael Levin, professor of biology and director of the Allen Discovery Center at Tufts University, who co-leads the new research.
“Toads normally reproduce in a certain way, but when you release [as células] from the rest of the embryo and gives them a chance to discover what it’s like to be in a new environment, they not only discover a new way to move, they also discover, apparently, a new way to reproduce.”
Robot or organism?
Stem cells are unspecialized cells that have the ability to develop into different types of cells. to make the xenobots, the researchers took live stem cells from frog embryos and left them to incubate. There is no gene manipulation involved.
“Most people think of robots as being made of metals and ceramics, but it’s not about what a robot is made of, but what it does, that acts on its own on people’s behalf,” said Josh Bongard, science professor University of Vermont computing and robotics specialist and lead author of the study.
“In that way, it’s a robot, but it’s also clearly an organism made of genetically unmodified frog cells.”
Bongard said he discovered that the xenobots, which initially had a sphere shape and were made up of about 3,000 cells, could replicate, but this happened rarely and only under specific circumstances. You xenobots used “kinetic replication” – a process known to occur at the molecular level but never before seen at the scale of whole cells or organisms, Bongard said.
With the help of artificial intelligence (AI), the researchers tested billions of body shapes to make the xenobots most effective in this type of replication.
The supercomputer came up with a C-shape reminiscent of Pac-Man, the video game from the 1980s. They found that it was able to find tiny stem cells in a Petri dish, assemble hundreds of them inside its mouth, and a few days later then the bundle of cells became new xenobots.
“The AI didn’t program these machines the way we normally think about writing code. She molded and carved and came up with this form of Pac-Man,” said Bongard.
“The form is, in essence, the program. The shape influences how the xenobots behave to amplify this amazing process.”
You xenobots they are very old technologies – think of a computer from the 1940s – and they still have no practical application. However, this combination of molecular biology and artificial intelligence could be used in a number of tasks in the body and the environment, according to the researchers. This can include things like collecting microplastics from the oceans, inspecting the root system, and regenerative medicine.
While the prospect of self-replicating biotechnology might raise concern, the researchers said the living machines were entirely contained in a laboratory and would be easily extinct, as they are biodegradable and regulated by ethical experts.
The research was partially funded by the Defense Advanced Research Projects Agency, a federal agency that oversees the development of technology for military use.
“A lot of things are possible if we take advantage of this kind of plasticity and the ability of cells to solve problems,” said Bongard.
The study was published in the peer-reviewed scientific journal PNAS on Monday (29).
Translated text. read the original in English.