Nanotechnology's beast of burden: bacteria

Via NewScientistTech:

Bacteria harnessed as micro propeller motors

One of the main challenges in developing microscale robots lies in miniaturising their power and propulsion. Now, researchers in the US may have found a solution to this problem, by exploiting the natural movement of bacteria to propel micro-objects through water.

Many bacteria propel themselves along in a fluid by rotating their corkscrew-like tails, called flagella, at relatively high speeds. These flagella are only around 20 nanometres in diameter and are about 10,000 nm long.

Motors made from bacterial flagella have been used as novel "nano-actuators" before (see Bacteria harnessed as miniature pumps), but Metin Sitti and Bahareh Behkam of Carnegie Mellon University in Pennsylvania, US, have taken another approach. They use the entire microorganism as the motor and control its on/off motion with chemicals...