Genetically Engineered Bacteria Etch Famous Faces Into a Petri Dish
Images of the Virgin Mary have appeared on grilled cheese sandwiches, trees and now in a petri dish. But that last appearance was no heavenly manifestation. It was a sign that Christopher Voigt’s photographic bacteria were working. This summer, his team at the University of California at San Francisco injected light-sensing and communication genes from various bacterial species into Escherichia coli. Then he projected an image (anything from a circle to Alfred Hitchcock’s profile) onto a plate of the bacteria. Each cell senses if it’s in the light, and those in the dark secrete a chemical. The illuminated bacteria next to the shadowed cells detect that cue and turn black, creating a line-drawing copy. Next, Voigt’s team will add color-sensing genes to E. coli so the bugs can make color images, a more complex step toward programming microorganisms to carry out useful jobs that require interpreting...