Strictly speaking, these life-forms do not have sex organs — or stomachs, brains or nervous systems. The one under the microscope consisted of about 2,000 living skin cells taken from a frog embryo. Bigger specimens, albeit still smaller than a millimeter-wide poppy seed, have skin cells and heart muscle cells that will begin pulsating by the end of the day. These are all programmable organisms called xenobots, the creation of which was revealed in a scientific paper in January, by Sam Kriegmana, Douglas Blackistonb, Michael Levinb, and Josh Bongarda,
A xenobot lives for only about a week, feeding on the small platelets of yolk that fill each of its cells and would normally fuel embryonic development. Because its building blocks are living cells, the entity can heal from injury, even after being torn almost in half. But what it does during its short life is decreed not by the ineffable frogginess etched into its DNA — which has not been genetically modified — but by its physical shape. And xenobots come in many shapes, all designed by roboticists in computer simulations, using physics engines similar to those in video games like Fortnite and Minecraft...
All of which makes xenobots amazing and maybe slightly unsettling — golems dreamed in silicon and then written into flesh. The implications of their existence could spill from artificial-intelligence research to fundamental questions in biology and ethics. "We are witnessing almost the birth of a new discipline of synthetic organisms," said Hod Lipson, a roboticist at the Columbia University who was not part of the research team. "I don't know if that's robotics, or zoology or something else."
An algorithm running for about 24 hours iterated through possible body shapes, after which the the two researchers tried "to sculpt cellular figurines that resembled those designs." They're now considering how the process might be automated with 3-D cell printers, and the Times ponders other future possibilities the researchers have hinted at for their Xenobots. ("Sweep up ocean microplastics into a larger, collectible ball? Deliver drugs to a specific tumor? Scrape plaque from the walls of our arteries?")