Magnetic bacteria may help build future bio-computers Published duration 7 May 2012

image caption Tiny magnets form inside magnetic bacteria

Magnet-making bacteria may be building biological computers of the future, researchers have said.

A team from the UK's University of Leeds and Japan's Tokyo University of Agriculture and Technology have used microbes that eat iron.

As they ingest the iron, the microbes create tiny magnets inside themselves, similar to those in PC hard drives.

The research may lead to the creation of much faster hard drives, the team of scientists say.

The study appears in the journal Small.

As technology progresses and computer components get smaller and smaller, it becomes harder to produce electronics on a nano-scale.

So researchers are now turning to nature - and getting microbes involved.

Magnetic bacteria

In the current study, the scientists used the bacterium Magnetospirilllum magneticum.

These naturally magnetic microorganisms usually live in aquatic environments such as ponds and lakes, below the surface where oxygen is scarce.

They swim following the Earth's magnetic field lines, aligning in the magnetic field like compass needles, in search of preferred oxygen concentrations.

When the bacteria ingest iron, proteins inside their bodies interact with it to produce tiny crystals of the mineral magnetite, the most magnetic mineral on Earth.

Having studied the way the microbes collect, shape and position these nano-magnets inside themselves, the researchers copied the method and applied it outside the bacteria, effectively "growing" magnets that could in future help to build hard drives.

"We are quickly reaching the limits of traditional electronic manufacturing as computer components get smaller," said lead researcher Dr Sarah Staniland of the University of Leeds.

"The machines we've traditionally used to build them are clumsy at such small scales.

"Nature has provided us with the perfect tool to [deal with] this problem."

Biological wires

Besides using microorganisms to produce magnets, the researchers also managed to create tiny electrical wires from living organisms.

They created nano-scale tubes made from the membrane of cells, grown in a lab-controlled environment with the help of a protein present in human lipid molecules.

A membrane is a biological film-like "wall" that separates a cell's interior from the outside environment.

Such tubes could in future be used as microscopic bio-engineered wires, capable of transferring information - just like cells do in our bodies - inside a computer, Dr Masayoshi Tanaka from Tokyo University of Agriculture and Technology told the BBC.

"These biological wires can have electrical resistance and can transfer information from one set of cells inside a bio-computer to all the other cells," he said.

Besides computers, such biological wires could even be used in future for human surgery because they are highly biocompatible, Dr Tanaka added.

"Various tiny wires have been already developed all over the world, but the biocompatibility is still problematic," he said.