Crystaline computer construction

Naturally occurring slime that lines the tunnels of a Wisconsin mine may offer a quicker way to build computer hard drives and lasers.

The slime contains natural pre-assembled nanocrystals of iron, formed by the action of bacteria, that assemble themselves into slabs.

Researcher Jillian Banfield, of the University of Wisconsin, asked scuba divers to collect samples of the orange bacterial deposits from the abandoned lead and zinc mine.

‘In the approximately 30 years since the mine flooded, tens of centimetre-thick orange stalactite and stalagmites and slime layers have accumulated,’ said Banfield.

The slime was rich in iron collected by two species of bacteria. The iron particles formed organised lattices and it is believed that the bacteria oxidised the iron and the charged iron particles either attached themselves to stalks of bacteria or oscillated in the water until they formed a clump.

Once clumped together they rotated and arranged themselves into a three-dimensional lattice.

Crystals normally grow atom by atom. However, a method of growing slabs of crystals may prove valuable for scientists looking for new ways to store information.

‘Examples include the external field required to switch a magnetised particle, of great importance in magnetotactic bacteria and hard disk drives, and the colour of light emission from a semiconductor, used for the fluorescent labelling of cells and in lasers,’ said Paul Altivisatos, a materials scientist at the University of California.

He added that nanocrystals have been seen as promising components for new artificial optical and electrical materials.