These "xenobots" are living machines designed by an evolutionary algorithm

Meet the xenobots: Tiny living robots have been created using cells taken from frog embryos. Each so-called xenobot is less than a millimeter across, but one can propel itself through water using two stumpy limbs, while another has a kind of pouch that it could use to carry a small load. The early research, published in Proceedings of the National Academy of Sciences, could help the development of useful soft robots that can heal themselves when damaged. Because they are made of living tissue, they also decay once they stop working. The researchers, from Tufts University, the University of Vermont, and the Wyss Institute at Harvard, hope such living robots could one day be used to clean up microplastics, digest toxic materials, or even deliver drugs inside our bodies (although this is obviously still all a long way off). The robots are constructed from heart cells, which spontaneously contract and relax like tiny pistons, and skin cells that provide more rigid structure.