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A self-replicating xenobot with the 'parent' coloured red and the 'baby' in green | Photo source Douglas Blackiston and Sam Kriegman

Researchers create living robots that can reproduce

Science

The programmable life form can reproduce by itself in a new and unique process

Spotted: Early last year, a team of researchers announced the creation of the world’s first living robots – known as ‘xenobots’. They were made up of bundles of stem cells taken from African clawed frogs and could be programmed to accomplish certain tasks, such as distributing a medicine inside a patient. Now, the researchers from the University of Vermont, Tufts University, and the Wyss Institute for Biologically Inspired Engineering at Harvard have announced that the xenobots have ‘learned’ how to reproduce by scooping up free-floating cells and assembling them into new clusters.

The shape of the xenobots, which is reminiscent of ‘Pac-Man’ from the famous arcade game, is the key to their ability to reproduce in this entirely novel way. To find the best shape to allow for the new type of reproduction—known as ‘kinematic’ replication—an evolutionary algorithm was run thousands of times.

The algorithm, which included basic rules about the biophysics of the cells involved, was run on a supercomputer and repeatedly reassembled a few hundred simulated cells into different forms and body shapes. Each time, the most successful simulated organisms were kept and refined, while the less successful were discarded. Finally, the most promising designs were selected for testing.

The designs were turned into living organisms using stem cells harvested from the embryos of African Xenopus laevis frogs. The cells were cut and joined to create a close approximation of the designs specified by the computer. Once joined, the cells began to spontaneously work together. After around five days, the xenobots were able to form spheres of around 3,000 cells that could push single cells together to form new xenobots.

This extraordinary development may sound like the opening sequence of a sci-fi movie, but the researchers say the intention is to better understand how organisms are organised, including how they store information and perform tasks. “The downside of living tissue is that it’s weak and it degrades,” explains Joshua Bongard, a computer scientist and robotics expert at the University of Vermont who co-led the study. “That’s why we use steel. But organisms have 4.5 billion years of practice at regenerating themselves and going on for decades.” He adds that, “These xenobots are fully biodegradable. When they’re done with their job after seven days, they’re just dead skin cells.”

While living, reproducing robots are, so far, unique, we have recently seen a huge expansion in the range and abilities of robots, especially those powered by AI. Robots are now being used for purposes as diverse as inspecting and repairing wind turbines and purifying DNA. It’s clear that practical uses for living robots cannot be far behind. 

Written By: Lisa Magloff

Email: josh.bongard@uvm.edu

Website: uvm.edu

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