Researchers have built the first ever “living robot”, or xenobot, by engineering frog embryos in the lab to behave like “living, programmable organisms,” an advance that may lead to computer designed life forms capable of delivering drugs in the human body.
The xenobots were millimetrewide robots, designed by stitching together different cell types from a frog embryo in specific ways so that they could move towards a target on their own, and also based on how the cells interacted with each other, the study, published in the journal PNAS, noted.
The bots were also engineered to pick up a payload — like a medicine that needs to be carried to a specific place inside a patient — and could heal themselves after being cut, according to the researchers. “These are novel living machines. They’re neither a traditional robot nor a known species of animal. It’s a new class of artifact: a living, programmable organism,” said study co-author Joshua Bongard, a computer scientist and robotics expert at the University of Vermont in the US.
According to the researchers, the xenobots may lead to novel machines in a wide range of fields like detecting toxic contamination in the environment, gathering microplastic in the oceans, and also scrapping out blocks in blood vessels.
The scientists developed a complex algorithm which could selflearn and evolve to create thousands of candidate designs for the new lifeforms. The algorithm reassembled a few hundred simulated cells into myriad forms and body shapes, over and over, in an attempt to achieve a task assigned by the scientists — like locomotion in one direction.
It ran on basic rules about the physics of what single frog skin, and cardiac cells can do. The researchers said that the computer, after a hundred independent runs of the algorithm, selected the most promising designs for testing. They then transferred the computer designs into life.
To achieve this, the research team first gathered stem cells — an unspecialised mass of cells with the potential to develop into any organ — from the embryos of African frogs, the species Xenopus laevis. The scientists separated these into single cells and left them to incubate. These cells were then individually cut using tiny forceps, and an even tinier electrode, and joined under a microscope into a close approximation of the designs specified by the computer, the researchers said.