Bacterial video

Photosensitive bacteria turned into an interactive screen

Grigory Kopiev, N+1

Italian researchers have created a screen in which the image is formed with the help of photosensitive bacteria and a projector that displays the negative image on the screen. The principle of operation of the screen is based on the fact that bacteria move faster in highly lit areas and accumulate in poorly lit areas. Article by Frangipane et al. Dynamic density shaping of photokinetic E.coli is published in the journal eLife.

Scientists often use bacteria as the basis of complex electronic devices. For example, with their help, it was possible to create a bleeding sensor in the intestine, a solar panel printed on paper, and even an array of logic gates for signal processing. In addition, some researchers have learned to draw with bacteria. Usually, substances that provoke the production of pigments or cause another spatially varying reaction are used for this, and some researchers have used light irradiation with different wavelengths for this. However, almost all of these developments are united by the fact that an image can be created only once.

Roberto Di Leonardo and his colleagues from the University of Rome La Sapienza created a screen with bacteria that allows images to be formed in it by irradiation with visible light and subsequently change this image. The system is based on genetically modified E. coli bacteria expressing the photosensitive protein proteorhodopsin. Due to this protein, irradiation increases the speed of movement of bacteria.

Installation diagram

The installation created by the researchers consists of a capillary with bacteria, on one side of which there is an LED that shines through the capillary, and on the other there is a translucent mirror that reflects the green color from the projector and passes the red color from the LED to the camera.

Since a bacterium can be considered as a randomly moving object, the density of bacteria placement in space is inversely proportional to the speed of movement. In other words, bacteria create a "congestion" in areas with low light. Because of this dependence of density on illumination, the researchers decided to project onto the capillary not the image itself, but its negative. Due to this, bacteria accumulate in areas where the intensity of the non-inverted image is high.

The authors also equipped the system with an algorithm that checks the real image formed by bacteria every 20 seconds and compares it with a sample. After calculating the differences, the algorithm creates a slightly modified projection, which should bring the real image closer to the standard.

Last year, American scientists created a strain of E. coli that reacts to red, green and blue colors and produces the appropriate pigments. In this way, scientists were able to create several color images, including a jumping Mario from a famous game.

Portal "Eternal youth" http://vechnayamolodost.ru