New discovery may change future of fiber optics

Researchers found that nanotubes conduct electricity and could benefit electronic devices.

Bacteria are everywhere – in Petri dishes, under microscopes and, now, in electronics.

A University professor recently assisted a former student in discovering a new, more natural way to create components for electronic devices.

The component is called a nanotube, and it comes from a certain kind of bacteria called Shewanella. The specimen is electronically conductive and, when exposed to light, the conductivity increases, said Michael Sadowsky, professor of soil, water and climate.

“You can use these little tiny structures to pass electrons, to make wires, and you can control how much electricity is being passed through these wires by using lights,” he said.

The multinational team that discovered the nanotubes was lead by Hor-Gil Hur, a former student of Sadowsky’s.

When the Shewanella was grown in the absence of air, but exposed to several elements and metals, it produced a residue. Sadowsky said that normally it would have been thrown away and assumed to be the result of a failed experiment.

Sadowsky said the team he worked with decided to test it instead.

They found that the material was made up of microscopic nanotubes.

“Nanotechnology is a new thing that’s going on,” he said. “There are applications of these that are enormous.”

Ji-Hoon Lee, a student of Hur, said the discovery of the nanotubes was surprising.

“We collaborated with some material scientists and they finally characterized the properties.”

These are the first nanotubes produced chemically that have a defined shape, Sadowsky said.

“Others have been made synthetically,” he said, “but they don’t have the length and the width properties. Ours are really long and really narrow.”

In order for the nanotubes to be put to use, they all need to be the same size and shape, Sadowsky said.

“To have a real, direct application, you need to have these uniform structures, and that’s something we’re going to work on toward the future,” he said.

Some applications of this nanotechnology could include sensor devices and, further down the road, fiber optic cables, Sadowsky said.

“We’re not there yet,” he said.

Fiber optic cables are currently made of glass, Jim Leger, a University electrical and computer engineering professor, said.

They function when light pulses through them, carrying information. They are the backbone of the Internet, he said.

Leger said the current makeup of fiber optic cables is not conductive like the nanotubes.

“What’s usually put into the cable is the fiber element itself and some sort of traditional electrical connection,” he said.

However, Leger did say that varying conductivity in a nanotube or other items would lend itself to other purposes.

“Anything that changes its properties, especially its conductivity, by the amount of light that you shine on it can obviously be used as a sensing element,” he said.

Lee said further research on nanotubes is being done in South Korea.

“We’ll collaborate in the near future,” he said.

Sadowsky said he looks forward to further research.

“The scale is limited to what we commit to it,” he said. “This is futuristic.”