By Jack Williams
A group of scientists have successfully created a masterpiece of the Mona Lisa using around one million genetically-modified pieces of bacteria.
Researchers from Rome University modified the E. Coli cells so that they would swiftly swim in response to light patterns, eventually grouping to replicate the famous da Vinci masterpiece.
In a similar experiment, E. coli cells moved from a portrait of Albert Einstein to create an image of Charles Darwin.
The team genetically-modified E. coli cells so that they would contain a protein called proteorhodopsin, which is found in ocean-dwelling bacteria, causing them to respond to light.
By doing so, the scientists hoped, the E. coli bacteria that then received more light would swim faster than others, eventually creating the patterns needed form the portraits.
Giacomo Frangipane, the lead author, said in a statement: “Much like pedestrians who slow down their walking speed 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.”
“We wanted to exploit this phenomenon to see if we could shape the concentration of bacteria using light.”
Using a projector that was beamed through a microscopic lens, scientists monitored how the E. coli changed their speed while swimming through different areas of light.
This then created the negative image of the Mona Lisa, which took around four minutes to form from the modified E. coli, a bacteria that can swim around 10 times its lenght in a second.
This happened because, as expected, the bacteria moved slower and concentrated in the darker parts of the image, while speeding up in parts that were more highly illuminated.
The Mona Lisa was chosen as a subject because it is so familiar and yet a challenging portrait to produce accurately.
The choice of morphing Einstein to Darwin was more emblematic of – like the research being carried out – crossing boundaries between physics and biology.
Roberto Di Leonardo, who worked on the project, which was published in eLife, said: “We see two main directions.
“The first one is more on the material science side.
“This bacteria could provide the living building blocks of functional microstructures which could be easily assembled using light and used for example as micro-sensors.
“More on the microrobotics and biomedical side, the possibility of taming millions of cells by shining light patterns could provide new strategies for manipulating, transporting and sorting single cells inside miniaturized laboratories on a chip.
“We have demonstrated 2D density shaping, we think that, by further engineering cells to produce some kind of ‘glue,’ it will be possible to build 3D structures layer by layer as in 3D printing.”