We wrote the word “Amazing” using naturally bioluminescent bacteria that microbiologist Siouxsie isolated from a fish bought from the supermarket.
“Drawing with bacteria onto agar is like drawing with invisible ink on jelly,” she says. Wherever bacteria are applied to the agar, they grow up overnight, and wherever they grow, they glow. “The solution of bacteria is colourless and dries pretty quickly so it’s very hard to see where you have already ‘painted’. And you have to apply just the right amount of pressure or you will cut into the agar.”
The process took about an hour and involved carefully tracing over the words using a paint brush that Siouxsie dipped into the solution of bacteria. “Getting the straight lines was really hard,” she says! “And we had to wait all night, until the bacteria had grown, to find out if it had worked. That was so nerve-wracking!”