Although robotic humanoids now perform backflips and autonomous drones fly in formation, even the most advanced robots are relatively primitive when compared with living machines. The running, jumping, swimming, and flying creatures that cover our planet's surface have long inspired engineers. Yet a subset of researchers are not just taking tips from living creatures. These roboticists, computer scientists, and bioengineers are combining artificial materials with living tissue, or making machines entirely from living cells. Some projects are even borrowing the tricks of life's greatest designer, evolution, to create robots that reimagine what the very term implies.
The field of evolutionary robotics, or allowing machines to develop their own forms without human intervention, is several decades old. Similarly, the idea of integrating living and artificial tissue is not a new one. The famed Terminator robot of the Arnold Schwarzenegger movies defined itself as a cybernetic organism, a mix of metal and flesh. In the real world, roboticist Francisco Valero-Cuevas of the University of Southern California has been testing his artificial nervous systems and spinal cords by hooking them up to biological tissue for years. In 2015, Harvard University bio-physicist Kevin Kit Parker and his colleagues designed an artificial sting ray powered by muscle cells harvested from rat hearts.