University researchers
redesign plants for life on Mars

Researchers at NC State are looking deep under water for clues on how to redesign plants for life deep in outer space.

Some of the stresses inherent with travel and life in space – extreme temperatures, drought, radiation and gravity, for example – are not easily remedied with traditional plant defenses.

So Dr. Wendy Boss, William Neal Reynolds Distinguished Professor of Botany, and Dr. Amy Grunden, assistant professor of microbiology, have combined their expertise to transfer beneficial characteristics from a sea-dwelling, single-celled organism called Pyrococcus furiosus into model plants like tobacco and Arabidopsis, or mustard weed.

P. furiosus is one of Earth’s earliest life forms, a microbe that can survive in extreme temperatures. It grows and dwells in underwater sea volcanoes where temperatures reach more than 100 degrees Celsius, or that of boiling water. Occasionally, the organism is spewed out into near freezing deep-sea water.

The NC State research, funded for two years and $400,000 by the NASA Institute for Advanced Concepts, entails extracting a gene – called superoxide reductase – from P. furiosus and expressing it in plants. That gene, one of nature’s best antioxidants, reduces superoxide, which in plants is a chemical signal given off when stressful conditions are encountered. This signal essentially puts the plant on alert, but staying on alert too long can be harmful: If not reduced quickly, the toxic superoxide will kill plant cells.

“The bottom line is that we were able to produce the P. furiosus superoxide reductase gene in a model plant cell line and to show that the enzyme has the same function and properties of the native P. furiosus enzyme,” Boss said.

Now that the concept of inserting a single gene from an extremophile into a plant has been proven, the researchers are working to insert associated genes in hopes of providing even more extreme-temperature protection to plants. And, they’re involving more great minds to come up with more answers – they’ve team-taught an honors undergraduate class called “Redesigning Living Organisms to Survive on Mars: Development of Virtual Plants” and plan to offer another class to investigate new mechanisms for reducing radiation damage in spring 2007.

Breaking Water to Extract
Hydrogen Made Easier

NC State scientists have discovered a nanoscale method for extracting hydrogen from water that requires only half the energy of current hydrogen production methods.

A water molecule interacts with a carbon nanostructure.

The researchers discovered that “defective” carbon nanotubes make it easier to “break” water molecules and extract hydrogen.

The discovery could have big implications, namely, lower hydrogen production costs, for industries looking to hydrogen as an alternative fuel.

The scientists – NC State Department of Physics professor Dr. Marco Buongiorno-Nardelli; Dr. Keith Gubbins, W.H. Clark Distinguished University Professor of Chemical and Biomolecular Engineering; post-doctoral researcher Milen Kostov; and students Erik Santiso and Aaron George – published their results in Physical Review Letters.

Carbon nanotubes are structures so small that it would take 1,000 of them stacked on top of one another to equal the thickness of a human hair. The nanotubes have many potential useful applications, one of them being the ability to facilitate chemical reactions.

The team discovered that naturally occurring defects in the nanotubes can increase the rate of a chemical reaction, because the atoms that form the defective nanotubes are essentially “incomplete,” thus making them more reactive.

“Normally, when you talk about chemical reactions in carbon nanotubes, you’re imagining that these reactions are happening in perfectly formed nanostructures,” said Buongiorno-Nardelli. “But the reality is that these structures have defects – places where the carbon atom network is broken. And these defects can influence the chemical reaction.”

And that is what the scientists discovered when they began running computer models to simulate what would happen if they used the defective nanostructures to break water molecules. The current method for extracting hydrogen from water involves heating water molecules to 2,000 degrees Celsius. The high temperature “breaks” the molecule, and hydrogen is released.

“We studied water for many months and ran many different calculations, and we ended up showing that if you want to break a water molecule, you spend a lot less energy if you do it on this defective carbon material than if you do it by simply heating the molecule until it breaks,” Buongiorno-Nardelli said.

'Alien Nanofiber' Could Put
Stop to Counterfeiters

Under a powerful microscope it looks like an alien – something out of Roswell, N.M., or “The X-Files.”

But a brand-new, tiny fiber dubbed the “alien nanofiber,” co-invented by a NC State textiles professor and a chemical engineering professor from the University of Puerto Rico, Mayaguez, has the potential to become a big deterrent to counterfeiters.

The new nanofiber looks like an alien, but has the potential to serve anti-counterfeiting purposes.

Dr. Juan Hinestroza, assistant professor of textile engineering, chemistry and science, and Dr. Carlos Rinaldi, assistant professor of chemical engineering at the University of Puerto Rico, Mayaguez, created novel nanoscale fibers that can be placed inside a garment or paper document and serve as a “fingerprint” that proves the garment or document is genuine.

At about 150 nanometers in diameter, the fibers are smaller than living cells and invisible to the naked eye. A nanometer is one-billionth of a meter; for comparison purposes, the Web site for the National Nanotechnology Initiative, a federal research and development initiative that coordinates multiagency efforts in nanoscale science, says that a human hair is about 80,000 nanometers wide, while a sheet of paper is about 100,000 nanometers wide.

The tiny fibers are designed to have within them even smaller nanoparticles with an electrical, magnetic or optical “signature” that can prove a product genuine. The product would need only be scanned, or read, by a device looking for the particular signature.

For example, Hinestroza says, name-brand clothing with nanofibers can be scanned at different points in the supply chain to ensure pirated clothing doesn’t get into retail outlets or into your closet. Passports with nanofibers can be scanned to ensure their legitimacy. Ostensibly, paper money with nanofibers would help ensure fake twenties don’t get into your wallet – or the grocer’s till.

“The fibers can essentially serve as molecular bar codes,” Hinestroza says. “We can control the position, frequency and distribution of particles inside the fibers, and their signature.”

He also says that manufacturers wouldn’t need to change the ways they make things in order to include the nanofibers.

“These fibers can be easily incorporated into existing textile manufacturing facilities,” Hinestroza said. “Textile products are the perfect vehicles for incorporating nanotechnology into commercial applications.”

The process used to create the nanofibers is called electrospinning, a textiles manufacturing process first used in the 1930s but now being put to use to create tiny fibers.

In their electrospinning research, the scientists apply electrical charges to water-based polymer solutions containing tiny nanoparticles, including magnetic particles or quantum dots, tiny particles that, depending on their size, display colors. When enough electrical charge is applied to the solution, an unstable jet – or narrow stream of solution and nanoparticles – moving like a whip through air, is formed. The whipping motion elongates the jet while the solvent evaporates, producing a tiny fiber containing the nanoparticles.

The researchers then tested the fibers and found the fibers had magnetic properties.

The research is sponsored by a National Science Foundation Nanoscale Exploratory Research grant, and by the NC State Nanotechnology Steering Committee.

Posted Oct. 28, 2005

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