Computer virus destroyed your hard drive? Don't worry, some day bacteria might build you a bigger and better one.
Hard drives store data on discs coated with a metallic film divided into tiny magnetic regions, each of which stores a single bit - the more regions you can squeeze on to a disc, the bigger the capacity. Now, a team at the University of Leeds, UK, have borrowed a trick from nature to build a new kind of hard drive.
Certain strains of bacteria absorb iron to make magnetic nanoparticles that let them navigate using the Earth's magnetic field. The team have extracted the protein behind this process and used it to create magnetic patterns that can store data. "We're using and abusing nature because it's had billions of years to do all of its experiments through evolution, so there is almost no point in us starting from scratch," says Sarah Staniland, who led the research (Small, vol 8, p 204).
Hard drives are usually made by "sputtering", in which clouds of argon ions are fired at a sheet of magnetic material, knocking off particles which are deposited as a thin film on a disc. Groups of these particles, called grains, form the magnetic regions on the drive, with around 100 grains corresponding to one bit.