Dozens of AI-engineered creatures called xenobots (C-shaped; beige) flanked by loose frog stem cells (white).
Douglas Blackiston and Sam Kriegman
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Douglas Blackiston and Sam Kriegman
Dozens of AI-engineered creatures called xenobots (C-shaped; beige) flanked by loose frog stem cells (white).
Douglas Blackiston and Sam Kriegman
Scientists say they have witnessed a pattern of replication never seen before in organic robots created in the lab using frog cells. Among other things, the findings could have implications for regenerative medicine.
The discovery involves a xenobot – a simple, “programmable” organism created by assembling stem cells in a Petri dish – and described by a team of researchers from the University of Tufts, Harvard University and the University of Vermont in an article published this week inside Proceedings of the National Academy of Sciences.
“You can think of this as using different cells [as] Douglas Blackiston, co-author of the study, told NPR.
The researchers hope that one day these xenobots – described by the same group in a paper announced nearly two years ago – can be programmed to perform useful functions such as finding cancer cells in the human body or trapping harmful microplastics in the ocean.
Xenobots are made of cells taken from African clawed frogs, or Xenopus laevis. Blackiston, a senior scientist at the Allen Center for Discovery at Tufts University and the Wyss Institute for Biologically Inspired Engineering at Harvard University, said the cells were not genetically modified at all, but simply is to combine in different arrangements to create xenobots.
An AI-designed xenobot (C-shaped; red) scans the stem cells that have been compressed into a ball.
Douglas Blackiston and Sam Kriegman
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Douglas Blackiston and Sam Kriegman
An AI-designed xenobot (C-shaped; red) scans the stem cells that have been compressed into a ball.
Douglas Blackiston and Sam Kriegman
Xenobots propel themselves using tiny hair-like structures called cilia. They tend to spin in a corkscrew fashion, which “turns out to be pretty good for collecting things,” such as other tiles, Blackiston said.
So the team used an artificial intelligence-driven computer simulation to see how they could manipulate xenobots into even better shapes at piling things up.
An innovative design brings an unexpected discovery
For that purpose, the xenobots’ original spherical shape “wasn’t the best design,” explains Blackiston. Instead, the computer suggested a C-shape similar to a snow plow or, as some have observed, Pac-Man. That conformation is highly effective at eroding and collecting loose stem cells, he said, then naturally form large piles.
But when xenobots Scanning frog stem cells loosely in the dish, the researchers observed something remarkable: piles of cells that made up copies of the original xenobots.
Of course, different forms of sexual and asexual reproduction are well known in biology.
But what xenobots have done – called kinetic self-replication – is novel in living organisms, said Michael Levin, a professor of biology at Tufts and an associate professor at the Wyss Institute. It happens at the molecular level, but “we are not aware of any organisms that can reproduce or reproduce in this way,” he said.
It takes about five days to make a clone under optimal conditions, the researchers say. “Children” do not carry the C-shaped body type of the parent generation, but revert to the original, less efficient spherical form.
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Xenobots are collections of living cells and have no brain or digestive system. But in a practical sense, they can be programmed – to digest other cells, as in this study, or eventually to do other things. That’s why researchers refer to them as tiny organic robots.
Levin told NPR: “The distinction between a robot and a creature isn’t nearly as clear-cut as … we once thought. “These creatures, they have the attributes of both.”
In fact, the idea of kinetic self-replication is not entirely new – it was first proposed in the late 1940s by the mathematician John von Neumann. He envisioned machines that could choose from basic robot parts to make copies of themselves, said Sam Kreigman, a postdoctoral fellow at the Wyss Institute and lead author of the paper. report, explain.
“We had a lot of people trying to build von Neumann machines from robot parts for a long time, and with very limited success,” says Kreigman.
“We found that if you simply assume that the robot has to be made of metal, circuit boards, and electronics, and you use living cells instead, the von Neumann machine does,” he told NPR. very easy to manufacture.
Some scientists have ethical concerns
But that concerns some scientists. Nita Farahany, a Duke University professor of law and philosophy, studies ethics in relation to new technologies and is not part of xenobot research. “Anytime we try to exploit life… [we should] realized its potential to go really poorly,” she said Smithsonian Magazine.
However, the researchers note that like a hypothetical von Neumann machine, a xenobot cannot replicate itself without raw materials. Therefore, there is almost no chance that they can escape from the laboratory and start reproducing on their own. All the researchers had to do was get rid of the loose stock of stem cells and nothing left to create new xenobots.
And since no genetic material comes from the parent xenobot, they can’t mutate or evolve on their own, Blackiston said.
“It would be like finding the disjointed parts of a human being and putting them together to create a replica,” he said. “So it’s hard to find a way [evolutionary] choice will act on that, because nothing is transferred between each generation – each generation is independent. “
What the researchers hope is that one day these xenobots and their self-regeneration abilities can be harnessed for the benefit of humanity.
“This is really the first step, but you can think deeper,” Blackiston said. “If we could program these things better, perhaps they could pick and move the specific types of cells we want, or help us shape something that we’re building in a dish for regenerative medicine.”
For Kreigman, what’s interesting is that “this form of transcription occurs spontaneously.” Of course, it requires very specific conditions, he said, but “it doesn’t need to be developed over billions of years,”
“We thought about how long it took for life to develop on Earth,” Kreigman said. “It’s a very long story, but here in a dish under the right conditions, we have found a whole new form of replication in organisms.”
And the discovery of a new form of self-regeneration, he says, suggests that “maybe life is more to be expected than not.”
