AI-enhanced frog stem cells start to replicate in entirely new ways In January of 2020, scientists from the University of Vermont announced they had built the first living robots; this week they have published reports that those robots, made from frog cells and called Xenobots, can reproduce and have found a new way to do so. The millimetre-sized xenobots are essentially a computer-designed …
Ah, this is obviously some strange usage of the word 'replicate' that I wasn't previously aware of.
To be fair, the paper is talking about robotic assembly of other self-similar robots. The fact that these robots are assembled from cellular matter is irrelevant to the discussion - except that ... it's really cool (or creepy) to talk about previously living cells being shredded, assembled into a sort of Frankenstein monster, and then, themselves, assembling other Frankenstein monsters from similarly shredded cellular material.
For those who didn't read the paper, the steps are as follows:
1) Take a frog stem cell and remove the contents
2) Take the cell husk and strip off the outer layer
3) Assemble the cell inner layers into a "robot"
4) Put robots in an environment filled with the inner linings of cell and watch the robots "assemble" copies of themselves.
I see this less of a great leap in self-assembling robotics (although the shape is interesting) and more a testament to the tenacity of life to go on even after it's been horribly mutilated. This type of experiment shows that the forces binding life isn't just about the DNA, RNA, or macro-scale organisation - it is far deeper.
> it is far deeper
I agree. This is in the uncanny valley between biochemistry (e.g. looking at enzyme-catalyzed organic reactions) and biology - examining the structure and behaviour of living organisms. I suppose that what I see in that video is just the complex cell wall structures organizing themselves into local energy-minimum conformations that resemble the assemblers. It's just very advanced crystallization. I guess it might have looked that way in the Primordial Soup, and look where that got us.
They are clumps of cells and not cell fragments. The stem cells, if left to their own devices in a suspension, clump into spheroids of epidermis with the outer cells producing cilia by which they swim. As far as I can make out what they've done is work out Conway-like rules about how they associate in clumps and from that have worked out a shape - something along the lines of the glider gun - which will assemble smaller similar shaped clumps from loose cells. They then carve up the self-assembled spheroids into this shape. The reconfigured clumps work as predicted.
Each generation, however, is smaller. As they don't actually grow the limit is reached with a generation that's too small to assemble another one. They don't acquire energy from external sources so even the unmolested spheroids will eventually fall apart. The system is not self-sustaining.
It looks as if it depends on some mechanism for interaction between cells which must be related to the mechanisms for growth, embryogenesis, repair and differentiation in the whole organism but which lacks the structure of the whole organism to direct it. It may offer some insight into how collections of single cellular organisms could come together to form simple invertebrates with more advanced behaviours.
You'll find a far more reasoned and better written description of what this research group has done and what they think they've learned by reading the Ars Technica article about it:
https://arstechnica.com/science/2021/11/mobile-clusters-of-cells-can-help-assemble-a-mini-version-of-themselves/
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