Friday 30 October 2009

Protein NanoTubes - Grow Your Own Window Cleaner



Self-cleaning skyscraper and car windows and solar panels that repel water and dirt, as well as high-power rechargeable batteries for electric vehicles could be some of the major applications of a Tel Aviv University nanotechnology discovery announced on Sunday evening. Pictured: Self assembling protein nanotubes like these could put window washers out of work.

The development of arrays of self-assembling peptide (protein) nanotubes was the work of Prof. Ehud Gazit of the university's department of molecular microbiology and biotechnology, together with his team of Lihi Adler-Abramovich, Daniel Aronov, Peter Beker, Maya Yevnin, Shiri Stempler, Ludmilla Buzhansky and Gil Rosenman, some of the department of physical electronics. Their innovation appears in the prestigious journal, Nature Nanotechnology.

Gazit was abroad on Sunday, but Adler-Abramovich - who is completing her doctorate in his lab - told The Jerusalem Post that the team has been working on nanotubes for six years and this specific project for two. "We thought of applications when we started, but the results were so impressive during our research that we added more," she said. Nanotechnology is the study of the control of matter on an atomic and molecular scale and involves structures sized 100 nanometers - each one-billionth of a meter - or smaller. A very short and inexpensive peptide chain comprised of only two amino acids and easy to synthesize in mass production is the basis of the technology.

"The self-assembly is carried out under high temperatures and in a vacuum. The peptide is as simple as that of aspertame, the artificial sweetener, she said. The nanotubes have the amazing characteristic of assembling themselves to look like "forests" of artificial grass and are hydrophobic, which means that they repel water, as well as dust particles. Thus, sealed, exterior windows of skyscrapers - which are difficult to clean unless someone rapels up them - would not attract dust, and when it rained, any residual dirt would just drop off without leaving a trace. Solar energy panels made of glass, whose efficiency is greatly reduced by dust because the solar radiation has to filter through, could repel dust if made of ordinary glass with the nanotech coating, said Adler-Abramovich.

Solar-energy "farms" in the desert where there is no rain would be able to repel dust to increase efficiency. If they need to be perfectly clean, a small spray of water on the glass could remove the dirt completely without anyone cleaning them, she said. The new technology would apparently put window washers out of work.

She said that another application for the nanotubes would be super capacitators that arrange themselves in great density to produce a rechargeable electric battery storing large amounts of power. These would release electricity quickly, making them ideal for cars that rely on rapid acceleration, even when going uphill. The nanotubes function in high temperatures and are very resistant, said Gazit's doctoral student, and they could also be applied for a variety of medical and biotech uses. Ramot, TAU's research and development arm, is already making contact with commercial companies that could turn the nanotechnology discovery into products.

Meanwhile, TAU's research authority has this year passed the $100 million mark for the first time. Since 2000, the total amount of budget funding from inside the university and outside has doubled. This is despite the slowdown in research investment funds from abroad due to the economic situation. Nevertheless, funds from the European Community for TAU research increased from $1m. in 2000 to $10m. today, which constitutes 18 percent of the total, compared to 11% from the US.

In the protected environment of a quartz tube in a laboratory at Victoria University the creeping spidery arms of nanotubes self-assemble themselves into existence. Professor John Spencer and his PhD student Kirsten Edgar have initiated the growth of these fascinating nanoscopic structures. But what are nanotubes? You may ask and why are they growing in a Victoria University Laboratory? The answer is that these nanoscopic structures discovered only 13 years ago are all the rage on the science scene. In an age with increasingly vast amounts of information and increasingly small devices to process it, the properties of these uncommonly small, very strong, electrically conducting materials are irresistible. If it were possible to control the growth of these tubes so that their size, shape and position could be pre-determined they would open the doors to a whole nano-world of possibilities: nano-electronics, nanotweezers, nanolithography, nanotube reinforced composites, data storage, solar storage, noble radioactive gas storage; the list is endless. John and Kirsten, however are concerned only with the synthesis of nanotubes, understanding how they grow and trying to control the type and size of tube that grows. There are so many different kinds of nanotubes: single wall, double wall, long, short, twisted, straight, skinny, fat and many more and the electronic and structural properties depend on these classifications. It is very difficult to sort the nanotubes once they are made so to get a single type of nanotube, required for a particular application the best idea is to control their growth from the beginning. This is the aim of research at Victoria University. It is, however no small task. Read more...

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