http://news.bbc.co.uk/2/hi/science/nature/4181197.stm
Tiny robots powered by living muscle have been created by scientists
But when biological cells become attached to silicon - are they alive?
"They're absolutely alive," Professor Montemagno told BBC News. "I mean the cells actually grow, multiply and assemble - they form the structure themselves. So the device is alive."
The notion is likely to disturb many who already have concerns about nanotechnology.