‘Living robots’ that reproduce could help us develop regenerative medicine

30 Nov 2021

AI-designed organisms push loose stem cells into piles as they move through their environment. Image: Douglas Blackiston and Sam Kriegman

Scientists hope the research behind these xenobots will open the door to more advanced forms of living machines and new forms of medicine.

Scientists have created a new form of ‘living robot’ that is able to replicate itself and perform simple tasks.

These xenobots are groups of living cells scraped from frog embryos and repurposed with computer design by researchers from the University of Vermont (UVM), Tufts University and the Wyss Institute at Harvard University.

The researchers developed the xenobots in a study announced last year and have now made new progress on their design and potential applications.

The living machines have developed a unique form of replication by gathering hundreds of single cells, compressing them together and creating a ‘baby’ version of themselves. This offspring turns into a new xenobot that can continue the replication cycle.

“People have thought for quite a long time that we’ve worked out all the ways that life can reproduce or replicate. But this is something that’s never been observed before,” said Tufts scientist Douglas Blackiston.

The scientists said this research could be used to create new living machines that can perform more complex tasks, such as pulling microplastics out of waterways or developing forms new medicine.

“If we knew how to tell collections of cells to do what we wanted them to do, ultimately that’s regenerative medicine, that’s the solution to traumatic injury, birth defects, cancer and ageing,” said co-leader of the research Michael Levin.

“All of these different problems are here because we don’t know how to predict and control what groups of cells are going to build. Xenobots are a new platform for teaching us.”

The new creatures were designed on a supercomputer at UVM that tested billions of shapes in simulations, to find the shape that would allow the cells to be effective at a motion-based ‘kinematic’ form of replication. This replication has been observed at the molecular level before, but it has never been seen at the scale of whole cells or organisms.

The result researchers got from the supercomputer was a cluster of cells with a single mouth, shaped like a Pac-Man character.

“We sent the results to Doug and he built these Pac-Man-shaped parent xenobots. Then those parents built children, who built grandchildren, who built great-grandchildren, who built great-great-grandchildren,” said lead author of the study Sam Kriegman.

While the notion of self-replicating living machines may seem frightening, the researchers noted that the millimetre-sized xenobots are contained in a laboratory, easily extinguished, and vetted by federal, state and institutional ethics experts.

Another co-lead of the research, Joshua Bongard, believes there is a moral imperative in understanding the conditions in which we can control this form of replication as “we need to create technological solutions that grow at the same rate as the challenges we face”.

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Leigh Mc Gowran is a journalist with Silicon Republic