Nanotube-producing bacteria show manufacturing promise

December 07, 2007

RIVERSIDE, Calif. - Two engineers at the University of California, Riverside are part of a binational team that has found semiconducting nanotubes produced by living bacteria - a discovery that could help in the creation of a new generation of nanoelectronic devices.

The research team believes this is the first time nanotubes have been shown to be produced by biological rather than chemical means. It opens the door to the possibility of cheaper and more environmentally friendly manufacture of electronic materials.

Study results appear in today's issue of the early edition of the Proceedings of the National Academy of Sciences.

The team, including Nosang V. Myung, associate professor of chemical and environmental engineering in the Bourns College of Engineering, and his postdoctoral researcher Bongyoung Yoo, found the bacterium Shewanella facilitates the formation of arsenic-sulfide nanotubes that have unique physical and chemical properties not produced by chemical agents.

"We have shown that a jar with a bug in it can create potentially useful nanostructures," Myung said. "Nanotubes are of particular interest in materials science because the useful properties of a substance can be finely tuned according to the diameter and the thickness of the tubes."

The whole realm of electronic devices which power our world, from computers to solar cells, today depend on chemical manufacturing processes which use tremendous energy, and leave behind toxic metals and chemicals. Myung said a growing movement in science and engineering is looking for ways to produce semiconductors in more ecologically friendly ways.

Two members of the research team, Hor Gil Hur and Ji-Hoon Lee from Gwangju Institute of Science and Technology (GIST), Korea, first discovered something unexpected happening when they attempted to remediate arsenic contamination using the metal-reducing bacterium Shewanella. Myung, who specializes in electro-chemical material synthesis and device fabrication, was able to characterize the resulting nano-material.

The photoactive arsenic-sulfide nanotubes produced by the bacteria behave as metals with electrical and photoconductive properties. The researchers report that these properties may also provide novel functionality for the next generation of semiconductors in nano- and opto-electronic devices.

In a process that is not yet fully understood, the Shewanella bacterium secretes polysacarides that seem to produce the template for the arsenic sulfide nanotubes, Myung explained. The practical significance of this technique would be much greater if a bacterial species were identified that could produce nanotubes of cadmium sulfide or other superior semiconductor materials, he added.

"This is just a first step that points the way to future investigation," he said. "Each species of Shewanella might have individual implications for manufacturing properties."
-end-
Myung, Yoo, Hur and Lee were joined in the research by Min-Gyu Kim, Pohang Accelerator Laboratory, Pohang, Korea; Jongsun Maeng and Takhee Lee, GIST; Alice C. Dohnalkova and James K. Fredrickson, Pacific Northwest National Laboratory, Richland, Wash.; and Michael J. Sadowsky, University of Minnesota.

The Center for Nanoscale Innovation for Defense provided funding for Myung's contribution to the study.

The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment of about 17,000 is projected to grow to 21,000 students by 2010. The campus is planning a medical school and already has reached the heart of the Coachella Valley by way of the UCR Palm Desert Graduate Center. With an annual statewide economic impact of nearly $1 billion, UCR is actively shaping the region's future. To learn more, visit www.ucr.edu or call (951) UCR-NEWS.

University of California - Riverside

Related Nanotubes Articles from Brightsurf:

Nanotubes in the eye that help us see
A new mechanism of blood redistribution that is essential for the proper functioning of the adult retina has just been discovered in vivo by researchers at the University of Montreal Hospital Research Centre (CRCHUM).

How plantains and carbon nanotubes can improve cars
Researchers from the University of Johannesburg have shown that plantain, a starchy type of banana, is a promising renewable source for an emerging type of lighter, rust-free composite materials for the automotive industry.

Exotic nanotubes move in less-mysterious ways
Rice University researchers capture the first video of boron nitride nanotubes in motion to prove their potential for materials and medical applications.

Groovy key to nanotubes in 2D
New research offers a groovy answer to the question of what causes carbon nanotubes to align in ultrathin crystalline films discovered at Rice.

Growing carbon nanotubes with the right twist
Researchers synthetize nanotubes with a specific structure expanding previous theories on carbon nanotube growth.

Clean carbon nanotubes with superb properties
Scientists at Aalto University, Finland, and Nagoya University, Japan, have found a new way to make ultra-clean carbon nanotube transistors with superior semiconducting properties.

Watching energy transport through biomimetic nanotubes
Scientists from the University of Groningen (the Netherlands) and the University of W├╝rzburg (Germany) have investigated a simple biomimetic light-harvesting system using advanced spectroscopy combined with a microfluidic platform.

Neural networks will help manufacture carbon nanotubes
A team of scientists from Skoltech's Laboratory of Nanomaterials proposed a neural-network-based method for monitoring the growth of carbon nanotubes, preparing the ground for a new generation of sophisticated electronic devices.

Photovoltaic nanotubes
Physicists discovered a novel kind of nanotube that generates current in the presence of light.

Chemical synthesis of nanotubes
For the first time, researchers used benzene -- a common hydrocarbon -- to create a novel kind of molecular nanotube, which could lead to new nanocarbon-based semiconductor applications.

Read More: Nanotubes News and Nanotubes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.