New Nanoscale Process Created by UCSB Scientists Will Help Computers Run Faster and More Efficiently

Atomic Force Microscope image of a square array of 15nm pores formed by the new technology.

Abstract:
Smaller. Faster. More efficient. These are the qualities that drive science and industry to create new nanoscale structures that will help to speed up computers.

Scientists at the University of California, Santa Barbara have made a major contribution to this field by designing a new nanotechnology that will ultimately help make computers smaller, faster, and more efficient. The new process is described in today's Science Express, the online version of the journal Science.

Santa Barbara, CA | Posted on September 25th, 2008

For the first time, the UCSB scientists have created a way to make square, nanoscale, chemical patterns -- from the bottom up --that may be used in the manufacture of integrated circuit chips as early as 2011. It is called block co-polymer lithography.

Five leading manufacturers, including Intel and IBM, helped fund the research at UCSB, along with the National Science Foundation and other funders. The university has already applied for patents on the new methods developed here, and it will retain ownership.

A multidisciplinary team led by Craig Hawker, materials professor and director of the Materials Research Laboratory at UCSB, with professors Glenn Fredrickson and Edward J. Kramer, have developed a novel process for creating features on silicon wafers that are between five and 20 nanometers thick. (A nanometer is the thickness of one-thousandth of a human hair.)

Hawker explained that for the future we need more powerful microprocessors that use less energy. "If you can shrink all these things down, you get both," he said "You get power and energy efficiency in one package."

He said that the industry is up against Moore's law, a trend that Gordon Moore, Intel co-founder, first described in 1965 in which the power of the microprocessor doubles every 18 months. "One of the problems is that the industry is now running into physical limitations," said Hawker. "You can't shrink things down any more with the current technology." One of the ways that microprocessors are made is by using a top-down technique called photolithography, which involves shining light onto the surface of a silicon wafer, and making patterns. He explained that the size of the wavelength of light is becoming a limiting factor, and so his team has invented a new way of creating smaller patterns.

"We've come up with this new blending approach, called block co-polymer lithography, or BCP," said Hawker. "It essentially relies on a natural self-assembly process. Just like proteins in the body, these molecules come together and self assemble into a pattern. And so we use that pattern as our lithographic tool, to make patterns on the silicon wafer."

Using this technique, the size of the features is about the same as that of the molecules. They are very small, between five and 20 nanometers. "With this strategy, we can make many more features," said Hawker, "and hence we can pack the transistors closer together and everything else closer together --using this new form of lithography."

When this technique has been tried before, the molecules spontaneously self assembled into hexagonal arrays; they look like bee hives. But since industry uses parallel lines on a square or rectangular grid, the hexagonal arrays have limited application.

"In this article, we've actually shown that by changing the structure of the molecules, and using two self-assembling procedures at the same time, we're actually able to get square arrays, for the first time," said Hawker. "So now you can start to marry the old technology with the new technology for the fabrication of microprocessors."

Hawker said that the new technology was designed to be compatible with current manufacturing techniques, giving it the potential to be a "slip-in" technology. "All the big microprocessor companies like Intel and IBM have invested billions of dollars in their fabrication plants," said Hawker. "They're not going to throw out that technology anytime soon. It is too big of an investment and would not make good business sense. This allows them to introduce a new technology using current tools in the same fabrication plants. So they don't have to make huge up front investments to bring this to manufacturing. That's a key feature."

An analogy that Hawker uses in describing the development of the new methodology of block co-polymers is that of mixing salad dressing. "Think of the block co-polymers as oil and water," said Hawker. "When you make salad dressing you shake up the bottle because the oil and water don't want to be together. They separate into two layers. You shake your salad dressing and you mix everything up into much smaller droplets. What we've done is taken two polymer molecules that hate each other and joined them together. And so they want to separate just like the oil and water in your salad dressing. But because we've molecularly joined them, they can't. And so they separate into very, very small droplets, or domains, based on the fact that they hate each other. Those are the BCPs."

He explained that the interesting feature about this work is that the scientists combined the repulsive force with another self-assembly force which is slightly attractive.

"What we do is take one BCP (made of two components that hate each other) another BCP (again made of two components that hate each other) and simply mix these together," said Hawker. "When we mix them together, we've designed groups on one chain to be attracted to groups on a different chain, and so they actually start to blend and mix together. It is this combination of all these forces trying to get away from each other, and attract to each other that allows us to make the square arrays. Whereas what nature gives you is hexagonal, if you just use a single component system."

The scientists design the BCPs to have specific structures. And they use simulation to define the structures that are needed to prepare. "We design the molecule by understanding what needs to happen during the self-assembly process," said Hawker. "We need one block to be oil-like and one block to be water-like. So that's our first level of sophistication. We then design the molecular weight or the size of the molecule, to give us the desired feature size."

In the next step, the scientists design into the oil block the sticky groups that will form this attractive interaction, and by controlling the number of sticky groups, different levels of phase separation and different structures are created.

Polystyrene is the oil-like block, and one of the water-soluble blocks is polyethylene glycol. Polyethylene glycol is found in shampoos and many consumer products. It's a non-toxic, water-soluble, biocompatible polymer. By putting those together, the polyethylene glycol loves the water and the polystyrene loves the oil, and they hate each other. Polystyrene is found in disposable coffee cups, and according to the scientists is a fairly cheap commodity material that if designed in the right way, becomes a high value added application.

"The key to this work is that we put all the information into those molecules," said Hawker. "From a molecular level, we've built all the information into them that will allow them to undergo controlled phase separation. And the key is then just simply blending of two specifically designed materials, and then all we do is spin that down into a thin film on a silicon wafer. And then we heat it, and all the information that is pre-built into the molecule does its thing, and gives us the structure. And so that's why it is a really cheap technique. Because all you have to do is heat things up and you get the structures that you desire."

So the team has created a bottom-up approach to making these nanostructures, whereas the standard photolithographic technique, shining light onto the wafer -- is a top down engineering approach that requires multimillion dollar equipment.

In addition to Craig Hawker, the authors contributing the research, which was performed at UCSB, are: Chuanbing Tang, a postdoctoral fellow at the Materials Research Laboratory; Glenn Fredrickson, professor of chemical engineering and director of the Mitsubishi Chemical Center for Advanced Materials; Erin M. Lennon, a graduate student with Glenn Fredrickson at the time of the work; and Edward J. Kramer, professor of materials and of chemical engineering. (Lennon is now a National Science Foundation Research Training Group postdoctoral scholar at Northwestern University.)

####

For more information, please click here

Contacts:
Gail Gallessich
gail.g@ia.ucsb.edu
805-893-7220

FEATURED RESEARCHERS

Craig Hawker
hawker@mrl.ucsb.edu
805-893-7161

Glenn Fredrickson
ghf@mrml.ucsb.edu
805-893-8308

Edward Kramer
edkramer@mrl.ucsb.edu
805-893-4999

Copyright © University of California, Santa Barbara

Source

Metals Self-Assemble Into Nanostructures

Cornell researchers have developed a way to self-assemble metals into complex nanostructures. This could lead to far more efficient conductors and breakthroughs in energy technology.

Alexander E. Braun, Senior Editor -- Semiconductor International, 8/18/2008 8:11:00 AM

Ever since mankind first began working metals, the only way to shape them has been the heat-and-beat approach. While this process may have increased in sophistication (nanotech uses e-beams or acids to cut or etch), the basic procedure has remained the same. Now, however, a group of Cornell University (Ithaca, N.Y.) researchers has developed a technique to self-assemble metals into complex nanostructures, which could radically change the traditional millenary process, possibly leading to new types of conductors that can carry more information than any other existing wire.

The research effort is headed by Ulrich Wiesner, professor of materials science and engineering; Francis DiSalvo, J.A. Newman Professor of chemistry and chemical biology; and Sol Gruner, a John L. Wetherill Professor of physics. They have developed a method of coating metal nanoparticles ~2 nm in diameter with a ligand, an organic compound that allows them to be dissolved in a liquid and mixed with a block copolymer composed of two different chemicals whose molecules link together to solidify in a predictable pattern. When the polymer and ligand are removed, the metal particles fuse into a solid structure.

According to Wiesner, this target has been pursued for over two decades. “This is a complex problem, because metals typically have very high surface energies,” he said, adding that nanoscopic metal particles tend to aggregate into clusters. “Once these clusters are formed, they cannot be rearranged. Thus, to get structure control over metals using any sort of a self-assembly process isn’t easy.”

The aggregation issues were overcome by designing particular ligand structures. Ligands are attached to the metal nanoparticles surface, making them soluble in the solvents used in the self-assembly process with the polymers. These also have charges that provide repulsive interactions, so that when they come close, they don’t necessarily click together and form irreversible aggregation states. The repulsive interactions enable them to flow past each other and accommodate structure-formation processes governed by the polymeric species added into the mixture.

By designing the metallic nanoparticles with tailored organic ligands and then working with block copolymers that structure-direct the nanoparticles, it became possible to make, for the first time, nanostructures in what the researchers refer to as the dense nanoparticle regime. The Cornell breakthrough lay in adding a ligand that creates high solubility in an organic solvent, allowing particles to flow even at high densities. The ligand layer surrounding each particle was made relatively thin to ensure that the volume of metal in the final structure would be sufficiently large to maintain its shape after the organic materials were removed.

A solution of ligand-coated platinum nanoparticles was mixed with a block copolymer. The nanoparticles solution combines with only one of the two polymers, and the two polymers assemble into a structure that alternates between small regions of one and the other, producing clusters of metal nanoparticles suspended in one polymer and arranged around the outside of the other polymer’s hexagonal shapes. Depending on the polymers, other patterns can be attained.

The material is then annealed in the absence of air, turning the polymers into a carbon scaffold that supports the shape into which the metal particles have been formed. Finally, the material is heated in air to oxidize the ligands and burn away the carbon. Because metal nanoparticles have a low surface melting point, they sinter into a solid structure.

Chemically self-assembled complex platinum nanostructure with uniform hexagonal ~10 nm pores. (Source: S. Warren and U. Wiesner, Cornell University)

The result was a platinum structure with uniform hexagonal pores ~10 nm across. This could be a significant energy technology development, because platinum is considered the best catalyst available for fuel cells and such a porous structure would enable fuel to flow and react over a larger surface.

Wiesner considers results obtained so far as extremely promising, because this is the first time it has been possible to structure metals in bulk ways. “What you can do with one metal, you can do with mixtures of metals,” he said. In principle, it should be possible to use the approaches developed by Cornell in thin films to lay down metallic structures in silicon solely through self-assembly processes.

“This is exciting,” Wiesner said, “but limited to the polymer’s properties. Being organic materials, polymers aren’t very etch-resistant, lack magnetic properties, and usually don’t offer high electronic conductivity.” However, if instead of working with polymers it were possible to use metal block copolymer composites, then all the desired properties — electron conduction, magnetism, etc. — would be available.

According to Wiesner, the next step is to attempt to do the same thing that they did in bulk, which lacks the surface interactions between the material and substrate, in thin films. It should be possible to lay down in a well-defined way metal lines on a substrate using such a simple self-assembly process.

This has enormous potential for Moore’s Law. “But the devil is typically in the details, and although these preliminary results are extremely promising, it yet remains to be proven whether these self-assembly processes can truly fabricate these kinds of structures on thin film and do so using multiple materials,” Wiesner warned. The researchers used platinum, because it is a good catalyst, and a mesoporous material with a high surface area that lends itself to catalysis applications.

However, for semiconductor applications, it may be necessary to use metal alloys, some of which have strong magnetic properties. There is much to be considered, such as whether these alloys would be nanostructured.

Source

Revving Up The World's Fastest Nanomotors

Green lines show results of "racing," where images a, b, c, and d represent the tracks left by various types of speeding nanomotors. The winner is "c," a "catalytic nanomotor" composed of gold and platinum nanowires supercharged with carbon nanotubes. Credit: Courtesy of the American Chemical Society.

by Staff Writers
Washington DC (SPX) May 05, 2008

In a "major step" toward a practical energy source for powering tomorrow's nanomachines, researchers in Arizona report development of a new generation of sub-microscopic nanomotors that are up to 10 times more powerful than existing motors. Their study is scheduled for the May 27 issue of ACS Nano, a monthly journal.

In the new study, Joseph Wang and colleagues point out that existing nanomotors, including so-called "catalytic nanomotors," are made with gold and platinum nanowires and use hydrogen peroxide fuel for self-propulsion. But these motors are too slow and inefficient for practical use, with top speeds of about 10 micrometers per second, the researchers say. One micrometer is about 1/25,000 of an inch or almost 100 times smaller than the width of a human hair.

Wang and colleagues supercharged their nanomotors by inserting carbon nanotubes into the platinum, thus boosting average speed to 60 micrometers per second. Spiking the hydrogen peroxide fuel with hydrazine (a type of rocket fuel) kicked up the speed still further, to 94- 200 micrometers per second. This innovation "offers great promise for self-powered nanoscale transport and delivery systems," the scientists state.

Source

Nanoengineering Artificial Lipid Envelopes Around Adenovirus by Self-Assembly

ACS Nano, 2008

ASAP Article

Digital Object Identifier: 10.1021/nn8000565

Article

Ravi Singh, Khuloud T. Al-Jamal, Lara Lacerda, and Kostas Kostarelos^*

Nanomedicine Laboratory, Centre for Drug Delivery Research, The School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom

^*Address correspondence to kostas.kostarelos@pharmacy.ac.uk.

ABSTRACT

We have developed a novel, reproducible, and facile methodology for the construction of artificial lipid envelopes for adenoviruses (Ad) by self-assembly of lipid molecules around the viral capsid. No alteration of the viral genome or conjugation surface chemistry at the virus capsid was necessary, therefore difficulties in production and purification associated with generating most surface-modified viruses can be eliminated. Different lipid bilayer compositions produced artificially enveloped Ad with physicochemical and biological characteristics determined by the type of lipid used. Physicochemical characteristics such as vector size, degree of aggregation, stability, and surface charge of the artificially enveloped Ad were correlated to their biological (gene transfer) function. In monolayer cell cultures, binding to the coxsackie and adenovirus receptor (CAR) was blocked using a zwitterionic envelope, whereas enhanced binding to the cell membrane was achieved using a cationic envelope. Envelopment of Ad by both zwitterionic and cationic lipid bilayers led to almost complete ablation of gene expression in cell monolayers, due to blockage of virion endosomal escape. Alternatively, artificial Ad envelopes built from lipid bilayers at the fluid phase in physiological conditions led to enhanced penetration of the vectors inside a three-dimensional tumor spheroid cell culture model and delayed gene expression in the tumor spheroid compared to nonenveloped adenovirus. These results indicate that construction of artificial envelopes for nonenveloped viruses by lipid bilayer wrapping of the viral capsids constitutes a general strategy to rationally engineer viruses at the nanoscale with control over their biological properties.

Source

Making GNA for nanotechnology

In the rapid and fast-growing world of nanotechnology, researchers are continually on the lookout for new building blocks to push innovation and discovery to scales much smaller than the tiniest speck of dust.

In the Biodesign Institute at Arizona State University, researchers are using DNA to make intricate nano-sized objects. Working at this scale holds great potential for advancing medical and electronic applications. DNA, often thought of as the molecule of life, is an ideal building block for nanotechnology because they self-assemble, snapping together into shapes based on natural chemical rules of attraction. This is a major advantage for Biodesign researchers like Hao Yan, who rely on the unique chemical and physical properties of DNA to make their complex nanostructures.

While scientists are fully exploring the promise of DNA nanotechnology, Biodesign Institute colleague John Chaput is working to give researchers brand new materials to aid their designs. In an article recently published in the Journal of the American Chemical Society, Chaput and his research team have made the first self-assembled nanostructures composed entirely of glycerol nucleic acid (GNA)-a synthetic analog of DNA.

"Everyone in DNA nanotechnology is essentially limited by what they can buy off the shelf," said Chaput, who is also an ASU assistant professor in the Department of Chemistry and Biochemistry. "We wanted to build synthetic molecules that assembled like DNA, but had additional properties not found in natural DNA."

The DNA helix is made up of just three simple parts: a sugar and a phosphate molecule that form the backbone of the DNA ladder, and one of four nitrogenous bases that make up the rungs. The nitrogenous base pairing rules in the DNA chemical alphabet fold DNA into a variety of useful shapes for nanotechnology, given that "A" can only form a zipper-like chemical bond with "T" and "G" only pair with "C."

In the case of GNA, the sugar is the only difference with DNA. The five carbon sugar commonly found in DNA, called deoxyribose, is substituted by glycerol, which contains just three carbon atoms.

Chaput has had a long-standing interest in tinkering with chemical building blocks used to make molecules like proteins and nucleic acids that do not exist in nature. When it came time to synthesize the first self-assembled GNA nanostructures, Chaput had to go back to basics. "The idea behind the research was what to start with a simple DNA nanostructure that we could just mimic."

The first self-assembled DNA nanostructure was made by Ned Seeman's lab at Columbia University in 1998, the very same laboratory where ASU professor Hao Yan received his Ph.D. Chaput's team, which includes graduate students Richard Zhang and Elizabeth McCullum were not only able to duplicate these structures, but, unique to GNA, found they could make mirror image nanostructures.

In nature, many molecules important to life like DNA and proteins have evolved to exist only as right-handed. The GNA structures, unlike DNA, turned out to be 'enantiomeric' molecules, which in chemical terms means both left and right-handed.

The only chemical difference between DNA and a synthetic cousin, GNA, is in the sugar molecule. GNA uses a three-carbon sugar called glycerol rather than the five-carbon deoxyribose used in DNA. The sugar provides the chemical backbone for nucleic acid polymers, anchoring a phosphate molecule and nitrogenous base (B). Credit: Biodesign Institute at Arizona State University

"Making GNA is not tricky, it's just three steps, and with three carbon atoms, only one stereo center," said Chaput. "It allows us to make these right and left-handed biomolecules. People have actually made left-handed DNA, but it is a synthetic nightmare. To use it for DNA nanotechnology could never work. It's too high of a cost to make, so one could never get enough material."

The ability to make mirror image structures opens up new possibilities for making nanostructures. The research team also found a number of physical and chemical properties that were unique to GNA, including having a higher tolerance to heat than DNA nanostructures. Now, with a new material in hand, which Chaput dubs 'unnatural nucleic acid nanostructures,' the group hopes to explore the limits on the topology and types of structure they can make.

"We think we can take this as a basic building block and begin to build more elaborate structures in 2-D and see them in atomic force microscopy images," said Chaput. "I think it will be interesting to see where it will all go. Researchers come up with all of these clever designs now."

Source

How falling spaghettis could lead to more complex nanotechnology self-assembly

Posted: April 14, 2008

(Nanowerk Spotlight) Self-assembly and self-organization are terms (read this discussion about the difference between the two) used to describe processes in which a disordered system of pre-existing components forms an organized structure or pattern as a consequence of specific, local interactions among the components themselves, without external direction. Self-organizing processes are common throughout nature and involve components from the molecular (e.g. protein folding) to the planetary scale (e.g. weather systems) and even beyond (e.g. galaxies). Self-assembly has become an especially important concept in nanotechnology. As miniaturization reaches the nanoscale, conventional manufacturing technologies fail because it has not been possible (yet) to build machinery that assembles nanoscale components into functional devices (for more on this, read Mind the gap - nanotechnology robotics vision versus lab reality). Until robotic assemblers capable of nanofabrication can be built, self-assembly - together with chemical synthesis - will be the necessary technology to develop for bottom-up fabrication.

The stability of covalent bonds enables the synthesis of almost arbitrary configurations of up to 1000 atoms. Larger molecules, molecular aggregates, and forms of organized matter more extensive than molecules cannot be synthesized bond-by-bond. Self-assembly is one strategy for organizing matter on these larger scales (Source).

The key to using self-assembly as a controlled and directed fabrication process lies in designing the components that are required to self-assemble into desired patterns and functions. Self-assembly reflects information coded – as shape, surface properties, charge, polarizability, magnetic dipole, mass, etc. – in individual components; these characteristics determine the interactions among them.

"It has long been recognized that whereas self-organization near thermodynamic equilibrium tends to attenuate fluctuations, leading to relatively simple geometries, self-organization far from equilibrium can amplify fluctuations into coherent oscillations, leading to much more complex structures" Dr. Ernesto Joselevich tells Nanowerk. While much of the work on molecular self-assembly has focused on equilibrium systems, leading to highly ordered arrays such as crystals, Joselevich points out that this universal principle of 'order through fluctuations' has not yet been widely applied to the self-assembly of complex structures at the nanoscale – although it is the essence of the emergence of order, complexity and life in the universe in spite of the second law of thermodynamics.

Joselevich, a Senior Scientist in the Department of Materials and Interfaces at the Weizmann Institute of Science in Israel, together with PhD students Noam Geblinger and Ariel Ismach, has just published a report in Nature Nanotechnology on an intriguing new type of nanotube structures – serpentines – strikingly more complex than those observed before (Self-organized nanotube serpentines).

"Here we show that combined surface- and flow-directed growth enable the controlled formation of uniquely complex and coherent geometries of single-walled carbon nanotubes, including highly oriented and periodic serpentines and coils" Joselevich explains to Nanowerk. "We propose a mechanism of non-equilibrium self-organization, in which competing dissipative forces of adhesion and aerodynamic drag induce oscillations in the nanotubes as they adsorb on the surface."

SEM image of a nanotube serpentine (Reprinted with permission from Nature Publishing Group)

So far, controlled formation of complex nanotube geometries like rings and loops has been achieved by directed assembly of preformed nanotubes, using templates and microfluidics. In these cases, the alignment was solely determined by the surface of the template, and not affected by external forces such as electric fields or gas flow.

"A few years ago, in experimenting with the growth of carbon nanotubes along atomic steps, we produced arrays of perfectly straight and parallel nanotubes" Joselevich explains the background to his latest paper. "While playing with different substrates, we noticed a few serpentines on some of our samples of single-walled carbon nanotubes (SWCNTs) grown on quartz. This phenomenon could not be explained by our previous mechanism of growth along steps, because it did not make sense why a nanotube growing along a step would suddenly make a U-turn, then after a certain length make another U-turn in the opposite direction, and after precisely the same length make an opposite U-turn, and so on. The serpentine shape was a highly complex organized structure whose formation was a mystery for us.

"One evening, I saw my toddler son playing with spaghetti, and realized that when the spaghetti fell on a bamboo mat, it fell down making wiggles and produced serpentine shapes very similar to those of the nanotubes serpentines that we had observed in our lab experiments."

'Falling-spaghetti mechanism' for the formation of self-organized nanotube serpentines

Joselevich's team hypothesized that the serpentines could form in a two-step mechanism, where the nanotubes first grow standing up from the surface, and at a later stage adsorb on the surface in an oscillatory fashion along the steps. "Once we understood this" he says, "we patterned the catalyst on stripes of amorphous silicon oxide to prevent growth along the steps of the quartz. Then we were able to fabricate thousands of nanotube serpentines and could systematically study their formation and properties."

The serpentines are made of SWCNTs with a very low concentration of defects and appear to have exactly the same electronic properties as regular SWCNTs. Hence they are expected to be either metallic or semiconducting depending on their diameter and chirality. The team's data show that the diameter and chirality remain constant along the entire serpentine, which can be longer than one millimeter.

Joselevich notes that the serpentine shape has very interesting geometric properties. It provides maximum coverage of a certain area by a single line and it packs the maximum contour length of a line on a minimum area. "Hence, you find this shape in many daily useful objects like heating and cooling devices, illumination and irrigation systems, etc. We would like to produce nanodevices that take advantage of the serpentine shape for analogous applications in a miniature size."

The Weizmann Institute team's self-organizing nanotube serpentines is a dramatic example of non-equilibrium self-organization or 'order through fluctuations' at the nanoscale. Joselevich believes that if we learn how to produce complex structures through non-equilibrium self-organization we will be able to produce a lot of new functional nanosystems with potential applications not previously thought possible.

By Michael Berger. Copyright 2008 Nanowerk LLC Link

IBM experimenting with DNA to build chips

The research uses DNA molecules to arrange carbon nanotubes into a grid that might function as a data storage device or to perform calculations.

By Michael Kanellos
Staff Writer, CNET News.com

Published: February 20, 2008, 4:00 AM PST

Will the building block of life become the building block of the semiconductor industry? It's possible.

Scientists at IBM are conducting research into arranging carbon nanotubes--strands of carbon atoms that can conduct electricity--into arrays with DNA molecules. Once the nanotube array is meticulously constructed, the laboratory-generated DNA molecules could be removed, leaving an orderly grid of nanotubes. The nanotube grid, conceivably, could function as a data storage device or perform calculations.

"These are DNA nanostructures that are self-assembled into discrete shapes. Our goal is to use these structures as bread boards on which to assemble carbon nanotubes, silicon nanowires, quantum dots," said Greg Wallraff, an IBM scientist and a lithography and materials expert working on the project. "What we are really making are tiny DNA circuit boards that will be used to assemble other components."

The work, which builds on the groundbreaking research on "DNA origami" conducted by California Institute of Technology's Paul Rothemund, is only in the preliminary stages. Nonetheless, a growing number of researchers believe that designer DNA could become the vehicle for turning the long-touted dream of "self-assembly" into reality.

Chips made on these procedures could also be quite small. Potentially, DNA could address, or recognize, features as small as two nanometers. Cutting-edge chips today have features that average 45 nanometers. (A nanometer is a billionth of a meter.)

"What we are really making are tiny DNA circuit boards that will be used to assemble other components."

--Greg Wallraff, IBM scientist

"There is nothing else out there that we can do that with," said Jennifer Cha, an IBM biochemist working on getting the biological and nonbiological molecules to interact.

Right now, products get manufactured in a top-down approach with machinery and equipment manipulating raw materials. In self-assembly, the intrinsic chemical and physical properties of molecules, along with environmental factors, coax the raw materials into complex structures. It works with snowflakes, after all.

Getting the raw materials to behave in a precise, orderly manner, however, remains a challenge, which is where DNA comes in. DNA consists of specific chemical bases (guanine, cytosine) that bind and react in somewhat predictable ways with each other.

"The sequence (of base pairs in DNA) is well known," said Cha. "Most people are acknowledging that DNA and these biological scaffolds are actually quite useful to at least pattern very small systems."

How it works
In creating chip arrays, DNA assembly might work as follows: scientists would first create scaffolds of designer DNA manipulated into specific shapes. Rothemund has made DNA structures in the shapes of circles, stars, and happy faces.

A pattern would then be etched into a photo-resistant surface with e-beam lithography and the combination of several interacting thin films. A solution of the designer DNA would then be poured on the patterned surface and the DNA would space themselves out according to the patterns on the substrate and the chemical/physical forces between the molecules.

The nanotubes would then be poured in. Interactions between the nanotubes and the DNA would occur until they formed the desired pattern. Single strand DNA, along with origami, could be used in concert.

Another key part in the system revolves around peptides that can bind to the DNA and a nonbiologically inspired molecule like a nanotube.

"Building a DNA scaffold is not trivial because you need the biological system to recognize something that doesn't exist at all in biology," said Cha. "We can also use these biomechanical scaffolds to position inorganic nanomaterials. Potentially, we could also use these biomechanical systems to synthesize inorganic materials."

Although it's early, progress is occurring. Researchers have published papers on how DNA can coil around nanotubes and disperse them in water. Papers detailing how DNA can arrange nanotubes will come soon. Future experiments will need to be conducted into aligning nanotubes into arrays. Other researchers in this field include Nadrian Seeman at New York University and Thom LaBean at Duke University.

IBM will also examine ways of employing DNA to sort nanotubes, said Cha. Not all nanotubes are equal. The arrangement and relative position of carbon atoms in a nanotube, called chirality, can change the properties of a nanotube. Some nanotubes can't conduct electricity, for instance, even though they were made with others that do conduct electrons. Separating good from bad nanotubes currently requires applying an electric field, soaking them in solutions, or selecting by hand.

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If DNA manufacturing can become a reality, worries about the pace of progress in the computing world slowing down because of the difficulties involved in following Moore's Law would likely fade, at least for a while. Chipmakers shrink the size of the features of their chips every two years. While this improves the performance, producing smaller circuits has strained the financial and technical resources of the industry. The limits of lithography (used to "draw" circuits) have prompted many, including Intel co-founder Gordon Moore, to predict that the pace of progress would slow down.

With DNA, chipmakers could phase out multibillion fabrication facilities stocked with lithography systems, which cost tens of millions of dollars, and the other "top-down" style equipment.

Potentially, DNA techniques could allow manufacturers to produce features that are smaller than patterns that could be achieved even with the most advanced lithography systems, predicted Wallraff. E-beam lithography, which is extremely difficult to use in mass manufacturing, goes down to 10 nanometers.

"Of course, the devil is in the details," said Wallraff. "These are self-assembly procedures and error rates--missing features could be the downfall."

http://www.news.com/IBM-experimenting-with-DNA-to-build-chips/2100-1008_3-6231183.html

Applied Nanotech Inc - ANI - enters the DNA scaffolding self-assembly picture

Biophysicist / Biochemist

Applied Nanotech, Inc., (Austin TX) is looking for a Biophysicist / Biochemist to help start a project in DNA electronics, sensors or similar applications. This could include using DNA scaffolding for self-assembly of devices or systems. Will require building a team, which may include collaborative efforts with university or other organizations or companies. Require writing proposals to help acquire funding support.

Education: PhD or equivalent required. Candidate should demonstrate good verbal and written command of the English language. US citizen or Green Card desired. Please send resumes to Jsoptick@appliednanotech.net

http://www.nano-proprietary.com/ANI/EmploymentANI.asp

The next frontier for information processing may lie at the interface of nanoelectronics and biotechnology.

DNA scaffolding
Special report: Minnesota's Digital Dynasty

An interdisciplinary team led by electrical and computer engineering professor Richard Kiehl is exploring the use of DNA as a programmable scaffolding for the self-assembly of nanoscale electronic components. As a model for fabricating and designing semiconductor devices and circuits, DNA offers two key advantages: size scale and programmability.

Most industry experts believe that within the next 10 to 15 years the ability to scale down conventional technologies will reach its limit. At that point, the operating principles of conventional devices—and the techniques used to fabricate them—will break down. The basic elements of the DNA molecule are at just the right scale, says Kiehl.

Self-assembly uses bio-recognition, a natural process in which one molecule is attracted to and binds with another to form small structures. In the case of DNA, the attraction can be programmed so that the molecules will spontaneously assemble in solution to achieve a desired result.

“It's possible to synthesize small versions of DNA molecules in the laboratory and program in whatever code you want,” says Kiehl. “And because the two strands of DNA have complementary codes that match up, you can design one strand of DNA in a certain way so it will match another strand and assemble a nanoscale structure this way."

The matched segments form a scaffolding on which nanoparticles are affixed at highly selective attachment points. It's an approach that offers the programmability and precision needed for assembling electronic circuitry on the nanoscale.

“We have to make a real paradigm shift,” Kiehl says. “Not only do we have to keep improving performance, but we also must look at the kinds of devices we can make at those scales and how we want to use them to process information."

To that end, the researchers are turning to the human brain for inspiration. They envision devices whose electrical characteristics resemble those of neuron-like electrical waveforms in the brain. Like certain regions of the brain, the devices would process information based on pattern recognition rather than on individual bits of information. It's a more sophisticated level of information processing than can be achieved using conventional computers.

Kiehl predicts there will be a wide range of applications for this technology, including signal processing, communications systems, and computer systems. “The higher end of this [work] will be things that computers can't do very well today because the operations they use are too restrictive. One is the ability to recognize a pattern, such as identifying a letter as being an 'A' or a 'B', or being able to identify a face.

“It won't be just making things faster and faster in the conventional way,” he says. “It will really be opening up new ways to process information in machines."

http://www.it.umn.edu/news/inventing/2000_Fall/nano_dnascaffold.html

3/26/2007 7:10:17 AM
US Department of Defense grant gives $6M to team of 9 scholars for the study of quantum electronic arrays

The U.S. Department of Defense (DoD) has awarded a team of nine scholars from six universities a grant of $6 million over five years to exploit precise biological assembly techniques for the study of quantum physics in nanoparticle arrays. This research will produce a fundamental understanding of quantum electronic systems that could impact future electronics.

Leading the effort is electrical and computer engineering professor Richard Kiehl of the University of Minnesota, who has wide experience in investigating the potential of novel fabrication techniques, physical structures and architectures for electronics. Kiehl has brought together a multidisciplinary team to develop biological strategies combining DNA, proteins and peptides with chemical synthesis techniques to construct arrays of nanoparticles and to systematically characterize the resulting quantum electronic systems.

Interactions between precisely arranged nanoparticles could lead to exotic quantum physics, as well as to new mechanisms for computing, signal processing and sensing. But even basic studies of such nanoparticle arrays have been hampered by the need to fabricate test structures with extreme control and precision. "By exploiting biology to precisely control size, spacing and composition in the arrays, we will be able to examine electronic, magnetic and optical interactions at much smaller scales than before," said Kiehl. "Our project blends some really fascinating science at the edges of biology, chemistry, materials science and physics. And, I'm excited about the chance to impact how electronic circuits could be engineered in the future."

The team members are UCLA professors Yu Huang (materials science), Kang Wang (electrical engineering) and Todd Yeates (biochemistry); New York University professors Andrew Kent (physics) and Nadrian Seeman (chemistry); University of Texas at Austin professor Allan MacDonald (physics); University of Pennsylvania professor Christopher Murray (chemistry & materials science); and Columbia University professor Colin Nuckolls (chemistry).

Kiehl and Seeman have previously collaborated in the first demonstrations of metallic nanoparticle self-assembly by DNA scaffolding, which will be central to this project. Seeman will exploit DNA nanotechnology to construct 2-D and 3-D scaffolding, while Huang and Yeates will use peptides and proteins to make nanoparticle clusters for assembly onto the scaffolding. Murray and Nuckolls will synthesize metallic and magnetic nanoparticles with organic shells that will self-assemble onto the scaffolding and control the interparticle coupling. Kent, Kiehl and Wang will carry out experiments to characterize the electronic, magnetic and optical properties of the arrays. MacDonald will provide theoretical guidance for the studies and analysis of the experimental results.

The award was made by the Army Research Office (Marc Ulrich, research topic chief) and is one of 36 recently made under the highly competitive DoD Multidisciplinary University Research Initiative (MURI).

http://nanotechwire.com/news.asp?nid=4466&ntid=&pg=51

Re Seeman - NANS - his company was ~$1 then - it is now a shell and sits at $0.012
http://finance.yahoo.com/q?s=NANS.OB

NANS Annual Report - 8-Jan-2008

ITEM 6. MANAGEMENT'S DISCUSSION AND ANALYSIS OR PLAN OF OPERATION

The following information should be read in conjunction with the consolidated financial statements and notes thereto appearing elsewhere in this Form 10-KSB. We have determined on December 1, 2007 to cease operations immediately and, at the request of our principal creditor appointed a director designated by such creditor to our Board of Directors. Immediately following such appointment, our existing directors resigned effective immediately and terminated their association with us. Accordingly, such creditor may be deemed to control us at the date of the filing of this Report. As a result of our cessation of operations and the termination of the License Agreement, we became a "blank check" or "shell company" whose sole purpose at this time is to locate and consummate a merger or acquisition with a private entity.
***

Certainly not greatly encouraging! Looks like the future is in the hands of the DOD grants and perhaps ANI - who knows!! I'm looking forward to my first DNA scaffold assembled....whatever - TV? ;-)