Maria Gregori and Ignacio Llatser at the Polytechnic University of Catalonia in Barcelona, Spain, envision a future in which nanobots in the body sense tumour cells and release anticancer drugs to fight them. But one machine can't defeat a tumour single-handedly; it needs some way of telling the others to swarm on the target.
The pair has come up with the idea of using bacteria with flagella, in this case a non-pathogenic strain of E. coli, to send the information. The idea is to encode a message in a DNA sequence that is inserted into each bacterium's cytoplasm. Each nanobot would contain bacteria inscribed with every message that could be needed.
Click "source" for more.