Scientists have genetically engineered bacteria to “talk” to each other in a new language, bringing us one step closer to turning cells into tiny robots that we can control by flooding them with chemicals.

Bacteria already communicate with each other by sending out chemical signals, in response to stress, for example, causing them to switch on genes in neighboring cells that change their behavior.

“You could use this approach as a Trojan horse idea to combat disease,” says Jeff Hasty at the University of California, San Diego. Modified cells of pathogenic bacteria could be introduced into a natural colony of the same cells, he says. Then, at a given chemical signal, the modified cells could be told to produce compounds that would kill off the bacteria.