Bacteria run engines

Many animals have worked over the ages to pull wagons: horses, donkeys, camels, dogs and even fleas. This list is now joined by productions that can only be seen under a microscope - bacteria

Japanese researchers have developed a method to use a specific type of crawling bacteria to power a microscopic motor. As with many simple engines, the Japanese micro-engine includes a rotating part - a rotor - designed in the shape of a flower with six petals. The flower is stabilized above a circular channel and supported by lugs. The entire device is built from the material nitrogen dioxide, SiO2.

The "workhorses" of the engine are bacteria from the species called Mycoplasma mobile, which are able to move very quickly... relative to bacteria. If you put them on a special substrate of proteins, these pear-shaped bacteria, which are one micrometer (millionth of a meter) long, begin to crawl. The researchers coated the channel under the rotor with these special proteins, and coated the lower part of the rotor with another suitable protein.

Then, the scientists released the bacteria in the channel and encouraged them to move in one direction. When they passed the lugs supporting the rotor they rubbed against it. This slight friction turns the motor. The rotation is slow compared to electric motors - about two rotations per second. But the researchers believe that they can increase the speed 100 times. The use of bacteria for mechanical purposes attracts the researchers because, unlike inanimate parts, the bacteria multiply and repair themselves - and all they need is sugar...