Bacteria and Liquid Crystals Combined
In one form or another, we are all likely familiar with liquid crystals, and whether we like it or not, we are also familiar with bacteria. Liquid crystals and bacteria however are not familiar with each other, but that has changed now. Researchers at the Argonne National Laboratory and Kent State University have placed bacteria in a liquid crystal medium, creating living liquid crystals, and made some interesting discoveries.
Typically liquid crystals will align into long, rod-like structures along a single dimension, called a director. The researchers took a colony of Bacillus subtilis and transferred it to the liquid crystal solution, where at first the bacteria moved along with the director. As more bacteria were added however, they started to affect the liquid crystals. Like many other bacteria B. subtilis uses a long tail called a flagellum to propel itself, by spinning the tail like a corkscrew. This motion disrupted the director and started creating a wave-like pattern in the liquid crystal. As even more bacteria were added, the bacteria started forming stripes through the director, at different orientations, and by depriving the bacteria of oxygen, the stripes could be erased.
The hope for this study is that it will lead to a better understanding of active materials, which could potentially consume energy from the environment. Also this research could impact how bacteria are studied because while flagella are nanometers wide, requiring an electron microscope to see, the wake left in the liquid crystals is visible under an optical microscope.
Source: Argonne National Laboratory