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Scientists build first living robots using frog stem cells

  • Published at 07:18 pm January 14th, 2020
Large adult African clawed frog swimming in dirty water
Large adult African clawed frog swimming in dirty water Bigstock

These millimetre-wide “xenobots” can move toward a target, perhaps pick up a payload - like a medicine that needs to be carried to a specific place inside a patient - and heal themselves after being cut

Researchers in the US have created the first living machines by assembling cells from African clawed frogs into tiny robots that move around under their own steam, The Guardian reports.

These millimetre-wide “xenobots” can move toward a target, perhaps pick up a payload - like a medicine that needs to be carried to a specific place inside a patient - and heal themselves after being cut.

“These are novel living machines,” says Joshua Bongard, a computer scientist and robotics expert at the University of Vermont (UVM) who co-led the new research. “They’re neither a traditional robot nor a known species of animal.” 

“It’s a new class of artifact: a living, programmable organism.”

The new creatures were designed on a supercomputer at UVM — and then assembled and tested by biologists at Tufts University. 

“We can imagine many useful applications of these living robots that other machines can’t do,” says co-leader Michael Levin who directs the Centre for Regenerative and Developmental Biology at Tufts, “like searching out nasty compounds or radioactive contamination, gathering microplastic in the oceans, travelling in arteries to scrape out plaque.”

The robots, which are less than 1mm long, are designed by an “evolutionary algorithm” that runs on a supercomputer. The program starts by generating random 3D configurations of 500 to 1,000 skin and heart cells. 

Each design is then tested in a virtual environment, to see, for example, how far it moves when the heart cells are set beating. The best performers are used to spawn more designs, which themselves are then put through their paces.

Because heart cells spontaneously contract and relax, they behave like miniature engines that drive the robots along until their energy reserves run out. The cells have enough fuel inside them for the robots to survive for a week to 10 days before keeling over.

The scientists waited for the computer to churn out 100 generations before picking a handful of designs to build in the lab. They used tweezers and cauterising tools to sculpt early-stage skin and heart cells scraped from the embryos of African clawed frogs, Xenopus laevis. The source of the cells led the scientists to call their creations - xenobots.

But xenobots also raise a bevy of ethical questions. If things go awry, humans may need protection against these and other forms of artificial life—or, perhaps, vice versa. 

“When you’re creating life, you don’t have a good sense of what direction it’s going to take,” says Nita Farahany, who studies the ethical ramifications of new technologies at Duke University and was not involved in the study. 

“Any time we try to harness life … [we should] recognize its potential to go really poorly.”