Scientists have demonstrated that large groups of bacteria can turn microgears millions of times larger than themselves, showing potential for "smart" biomechanical systems.
Scientists from Northwestern University and the U.S. Department of Energy's Argonne National Laboratory observed several hundred microbes with random movement gather to push the spokes of a microscopic gear. With multiple gears arranged in a system, the bacteria -- the common Bacillus subtilis -- demonstrated synchronous movement.
Interestingly, the research team could manipulate the speed of the mechanical movement by controlling the amount of oxygen in the suspension solution: reduced oxygen naturally slowed the activity of the aerobic bacteria; reintroduced oxygen "woke" the bacteria up.
Eliminating the oxygen completely put the bacteria into a kind of "sleep" that stops them completely.
The team's findings could lend insight into the design of "smart materials" -- bio-inspired, dynamically adaptive materials made of a combination of bacteria or man-made nanorobots and hard materials that could be used to repair damage or power microdevices.
Here's a video of the bacteria in action:
And another, with a different gear design: