According to a BBC News article, nanotechnology researchers at the University of California's NanoSystems Institute in Los Angeles have created tiny robots powered by living muscle tissue. The scientists took heart cells from rats and combined them with tiny silicon and plastic "skeletons". The muscle cells attach to the specific points on the hardware and begin to grow and function as muscles, moving the two-footed cyborgs around. Are the tiny robots alive? Professor Carlo Montemagno, one of the researchers, says, "They're absolutely alive. I mean the cells actually grow, multiply and assemble - they form the structure themselves. So the device is alive." For more, see also an older article in New Scientist.