This recreation of the Mona Lisa may be a little blurry, but it’s still the best effort at reproducing a masterpiece using genetically modified bacteria that we’ve ever seen.
The picture was made by Italian scientists at the Sapienza University of Rome. Rather than trying to pull off some kind of germ-based art fraud, the researchers were investigating methods for making large populations of bacteria move around on command. To do this, the team modified the DNA of E. coli bacteria so they would produce the protein proteorhodopsin in their tiny flagella – the ‘tails’ which the bacteria use to move around. Proteorhodopsin is light-sensitive, and is used in some microorganisms to generate energy.
“Much like pedestrians who slow when they encounter a crowd, or cars that are stuck in traffic, swimming bacteria will spend more time in slower regions than in faster ones,” said lead author Dr Giacomo Frangipane. “We wanted to exploit this phenomenon to see if we could shape the concentration of bacteria using light.”
The proteorhodopsin in the bacteria’s flagella meant they could be made to move either faster or slower, depending on how much light they were exposed to. Slower-moving bacteria would clump together (to form dark areas in the picture), while faster-moving bacteria spread further apart (to create lighter areas in the picture).
The researchers hope that by learning how to control bacterial movement, we may eventually be able to create microscopic ‘machines’ to deliver drugs within the body. The technique could also have applications in 3D printing.
This is an extract from issue 327 of BBC Focus magazine.
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