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The Nanotechnology Center includes class 100 (ISO 5) to class 10'000 (ISO 7) cleanroom facilities.(Image Credit: IBM)

IBM and ETH Zurich, a European science and engineering university, recently opened the Binnig and Rohrer Nanotechnology Centerlocated on the campus of IBM Research – Zurich. The facility is the centerpiece of a 10-year strategic partnership in nanoscience between IBM and ETH Zurich where scientists will research novel nanoscale structures and devices to advance energy and information technologies. The new Center is named for Gerd Binnig and Heinrich Rohrer, the two IBM scientists and Nobel Laureates who invented the scanning tunneling microscope at the Zurich Research Lab in 1981, thus enabling resear �chers to see atoms on a surface for the first time. Scientists and engineers from IBM and ETH Zurich will pursue joint and independent projects, ranging from exploratory research to applied and near-term projects including new nanoscale devices and device concepts as well as generating insights about their scientific foundations at the atomic level. Three ETH professors and their teams have moved into the new building and will conduct part of their research in nanoscience on a permanent base. Even more ETH researchers will benefit from the partnership and be able to use the excellent infrastructure for various projects. One focus of IBM's research in the Center is put on exploring the "next switch"-- the future building blocks for better, faster and more energy efficient chips and computer systems. For example, IBM scientists are currently exploring semiconducting nanowires--tiny hairlike structures-- to potentially increase the energy efficiency of computing devices by 10 times. In addition, through novel device concepts, such nanowires-transistors could virtually consume zero energy while in passive or standby mode. Additional research areas include micro- and nanoelectromechanical systems, spintronics, organic electronics, carbon-based devices, functional materials, cooling, three-dimensional integration of computer chips, opto-electronics and optical data communication in computers as well as silicon nanophotonics.

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Rather than breaking down, a nanocomposite material stiffens under strain, a finding that in the future may be useful in the development of artificial cartilage.(Image Credit: Ajayan lab, Rice University)

A synthetic material gets stronger from repeated strain much like the body strengthens bone and muscle after repeated workouts. The trick to stiffening polymer-based nanocomposites with carbon nanotube fillers lies in the complex, dynamic interface between nanostructures and polymers in carefully engineered nanocomposite materials. Researchers at Rice University discovered the interesting property while testing the high-cycle fatigue properties of a composite made by infiltrating vertically aligned, multi-walled nanotubes with polydimethylsiloxane, an inert rubber polymer. Instead of damaging the material, repeatedly loading it seemed to make it stiffer. Using dynamic mechanical analysis (DMA) to test the material, the researchers found that after 3.5 million compressions (five per second) over about a week’s time, the stiffness of the composite had increased by 12 percent and showed the potential for even further improvement. “It took a bit of tweaking to get the instrument to do this,” says Brent Carey, a graduate student at Rice University working in the lab of Pulickel Ajayan, professor of mechanical engineering and materials science and of chemistry at Rice University. “DMA generally assumes that your material isn’t changing in any permanent way. In the early tests, the software kept telling me, ‘I’ve damaged the sample!’ as the stiffness increased. I also had to trick it with an unsolvable program loop to achieve the high number of cycles.” Materials scientists know that metals can strain-harden during repeated deformation, a result of the creation and jamming of defects—known as dislocations—in their crystalline lattice. Polymers, which are made of long, repeating chains of atoms, don’t behave the same way. Researchers are not sure precisely why their synthetic material behaves as it does.

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Nano-oscillatorsImage Credit: University of California, Riverside

Even the smallest devices, assembled at the molecular level, need motors and oscillators. UC Riverside Mechanical Engineering Professor Qing Jiang thinks bundling groups of carbon nanotubes together could make an ultra-efficient and accurate nano-oscillator. In the rapidly developing field of nanotechnology -- doing things at a scale 100,000 times narrower than a human hair -- nanodevices are becoming an increasingly key component in everything from drug delivery to improving or even replacing the microprocessors in computers or optical switches in telecommunications networks. “We’re looking at the very fundamentals of machinery in the nanoscopic world and what it takes to move the components of these machines, ultra-fast, super-efficient and with extreme precision” Jiang said. “A nano-motor generating rotational motion, a nano-oscillator (like a piston) generating linear motion forward and backward. We’re looking at how best to generate these motions in a nano-environment.”  Jiang’s earlier work, done mostly with multi-walled carbon nanotube oscillators, in which a narrow nanotube is encased in a larger nanotube, encountered two limitations -- frequency and friction. With increased frequency, beyond the benchmark one gigahertz (a billion cycles per second), increased energy dissipation creates a lot of heat, which reduces the efficiency of the tiny pistons. His current work, with bundles of single-walled carbon nanotubes encased in an additional layer of single-walled carbon nanotubes outperformed their multi-walled counterparts and generated less heat and friction problems.

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(Image Credit: University of Nottingham)

Scientists at the University of Nottingham have made a major breakthrough that could help shape the future of nanotechnology, by demonstrating for the first time that 3-D molecular structures can be built on a surface. The discovery could prove a significant step forward towards the development of new nano devices such as cutting-edge optical and electronic technologies and even molecular computers. The team of chemists and physicists at Nottingham have shown that by introducing a ‘guest’ molecule they can build molecules upwards from a surface rather than just 2-D formations previously achieved. A natural biological process known as ‘self-assembly’ meant that once the scientists introduced other molecules on to a surface their host then spontaneously arranged them into a rational 3-D structure. Professor Neil Champness said: “It is the molecular equivalent of throwing a pile of bricks up into the air and then as they come down again they spontaneously build a house. “Until now this has only been achievable in 2-D, so to continue the analogy the molecular ‘bricks’ would only form a path or a patio but our breakthrough now means that we can start to build in the third dimension. It’s a significant step forward to nanotechnology.” Previously, scientists have employed a technique found in nature of using hydrogen bonds to hold DNA together to build two-dimensional molecular structure.

The new process involved introducing a guest molecule -- in this case a ‘buckyball’ or C60 -- on to a surface patterned by an array of tetracarboxylic acid molecules. The spherical shape of the buckyballs means they sit above the surface of the molecule and encourage other molecules to form around them. It offers scientists a completely new and controlled way of building up additional layers on the surface of the molecule. The work is the culmination of four years’ of research led by Professors Champness and Beton from the School of Chemistry and the School of Physics and Astronomy, which has been funded with a total of £3.5 million from the Engineering and Physical Sciences Research Council.

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Twisting spires are one of the 3D shapes researchers at the University of Michigan were able to develop using a new manufacturing process.(Image Credit: University of Michigan, A. John Hart )

Twisting spires, concentric rings, and gracefully bending petals are a few of the new three-dimensional shapes that University of Michigan engineers can make from carbon nanotubes using a new manufacturing process. The process is called “capillary forming,” and it takes advantage of capillary action, the phenomenon at work when liquids seem to defy gravity and spontaneously travel up a drinking straw. The new miniature shapes have the potential to harness the exceptional mechanical, thermal, electrical, and chemical properties of carbon nanotubes in a scalable fashion, said A. John Hart, an assistant professor in the Department of Mechanical Engineering and in the School of Art & Design. The 3D nanotube structures could enable countless new materials and microdevices, including probes that can interface with individual cells, novel microfluidic devices, and lightweight materials for aircraft and spacecraft.

“It’s easy to make carbon nanotubes straight and vertical like buildings,” Hart said. “It hasn’t been possible to make them into more complex shapes. Assembling nanostructures into three-dimensional shapes is one of the major goals of nanotechnology and nanomanufacturing. The method of capillary forming could be applied to many types of nanotubes and nanowires, and its scalability is very attractive for manufacturing.” Hart’s method starts by patterning a thin metal film on a silicon wafer. This film is the iron catalyst that facilitates the growth of vertical carbon nanotube “forests” in patterned shapes. It’s a sort of template. Rather than pattern the catalyst into uniform shapes such as circles and squares, Hart's team patterns a variety of unique shapes such as hollow circles, half circles, and circles with smaller ones cut from their centers. The shapes are arranged in different orientations and groupings, creating different templates for later forming the 3D structures using capillary action.
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(Image Credit: University of Twente )

Earlier musical instruments with these minimal dimensions only produced tones that are inaudible to humans. But thanks to ingenious construction techniques, students from the University of Twente in the Netherlands have succeeded in producing scales that are audible when amplified. To do so, they made use of the possibilities offered by micromechanics: the construction of moving structures with dimensions measured in micrometres (a micrometre is a thousandth of a millimetre). These miniscule devices can be built thanks to the ultra-clean conditions in a 'clean room', and the advanced etching techniques that are possible there. "You can see comparable technology used in the Wii games computer for detecting movement, or in sensors for airbags", says PhD student Johan Engelen, who devised and led the student project. The tiny musical instrument is made up of springs that are only a tenth of the thickness of a human hair, and vary in length from a half to a whole millimetre. A mass of a few dozen micrograms is hung from these springs. The mass is set in motion by so-called 'comb drives': miniature combs that fit together precisely and shift in relation to each other, so 'plucking' the springs and creating sounds. The mass vibrates with a maximum deflection of just a few micrometres. This minimal movement can be accurately measured, and produces a tone. Each tone has its own mass spring system, and six tones fit on a microchip. By combining a number of chips, a wider range of tones can be achieved. "The tuning process turned out to be the greatest challenge", says Engelen. "We can learn a lot from this project for the construction of other moving structures. Above all, this is a great project for introducing students to micromechanics and clean room techniques."  The video below shows a recent concert using the technology.
 httpv://vimeo.com/15359134

Making music on a microscopic scale from University of Twente on Vimeo.

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A visualization of the nanoscale interaction between a semiconducting substrate (below) and graphene. (Credit: Joe Lyding, U. Illinois)

New findings from the laboratory of Beckman Institute for Advanced Science and Technology (University of Illinois at Urbana-Champaign) researcher Joe Lyding are providing valuable insight into graphene, a single two-dimensional layer of graphite with numerous electronic and mechanical properties that make it attractive for use in electronics. Lyding, who heads the Nanoelectronics and Nanomaterials group at Beckman, and his lab report using a dry deposition method they developed to deposit pieces of graphene on semiconducting substrates and on the electronic character of graphene at room temperature they observed using the method. The researchers wrote this of graphene’s potential, especially as compared to its elemental cousin, carbon nanotubes, for use in electronics and other applications: “It exhibits the quantum hall effect, even at room temperature, and its optical transparency is directly related to the fine structure constant. Graphene is more and more being thought of as a fairly strong and elastic membrane (with an associated potential as a material for NEMS applications). Unlike carbon nanotubes, graphene can be patterned using standard e-beam lithographic techniques, making it an attractive prospect for use in semiconductor devices.” To reach that goal, issues associated with graphene must be overcome, and the research gives insight into a much-needed step in that direction: understanding substrate-graphene interactions toward integration into future nanoelectronic devices. The project investigated the electronic character of the underlying substrate of graphene at room temperature and reports on “an apparent electronic semitransparency at high bias of the nanometer-sized monolayer graphene pieces observed using an ultrahigh vacuum scanning tunneling microscope (UHV-STM) and corroborated via first-principles studies.” This semitransparency was made manifest by observation of the substrate atomic structure through the graphene.
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A scanning electron microscope image of the silver nanowires in which the cotton is dipped during the process of constructing a filter. The large fibers are cotton. (Credit: Stanford University)

By dipping plain cotton cloth in a high-tech broth full of silver nanowires and carbon nanotubes, Stanford University researchers have developed a new high-speed, low-cost filter that could easily be implemented to purify water in the developing world. Instead of physically trapping bacteria as most existing filters do, the new filter lets them flow on through with the water. But by the time the pathogens have passed through, they have also passed on, because the device kills them with an electrical field that runs through the highly conductive "nano-coated" cotton. In lab tests, over 98 percent of Escherichia coli bacteria that were exposed to 20 volts of electricity in the filter for several seconds were killed. Multiple layers of fabric were used to make the filter 2.5 inches thick. "This really provides a new water treatment method to kill pathogens," said Yi Cui, an associate professor of materials science and engineering. "It can easily be used in remote areas where people don't have access to chemical treatments such as chlorine." Cholera, typhoid and hepatitis are among the waterborne diseases that are a continuing problem in the developing world. Cui said the new filter could be used in water purification systems from cities to small villages.
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University of Pennsylvania researchers developed a carbon-based, nanoscale platform to electrically detect single DNA molecules. Electric fields push tiny DNA strands through atomically-thin graphene nanopores that ultimately may sequence DNA bases by their unique electrical signature. (Credit: University of Pennsylvania; Art: Robert Johnson)

Researchers at the University of Pennsylvania have developed a new, carbon-based nanoscale platform to electrically detect single DNA molecules. Using electric fields, the tiny DNA strands are pushed through nanoscale-sized, atomically thin pores in a graphene nanopore platform that ultimately may be important for fast electronic sequencing of the four chemical bases of DNA based on their unique electrical signature. The pores, burned into graphene membranes using electron beam technology, provide Penn physicists with electronic measurements of the translocation of DNA. “We were motivated to exploit the unique properties of graphene — a two-dimensional sheet of carbon atoms — in order to develop a new nanopore electrical platform that could exhibit high resolution,” said Marija Drndi, associate professor in the Department of Physics and Astronomy in Penn’s School of Arts and Sciences. “High resolution of graphene nanopore devices is expected because the thickness of the graphene sheet is smaller than the distance between two DNA bases. Graphene has previously been used for other electrical and mechanical devices, but up until now it has not been used for DNA translocation." The research team had made graphene nanopores in a study completed two years ago and in this study put the pores to work. Graphene nanopore devices developed by the Penn team work in a simple manner. The pore divides two chambers of electrolyte solution and researchers apply voltage, which drives ions through the pores. Ion transport is measured as a current flowing from the voltage source. DNA molecules, inserted into the electrolyte, can be driven single file through such nanopores.
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Reed-Sternberg cells can be distinguished by their red outline, blue and white internal staining, and their lack of green staining. (Credit: Emory)

The tunable fluorescent nanoparticles known as quantum dots make ideal tools for distinguishing and identifying rare cancer cells in tissue biopsies, Emory and Georgia Tech scientists have demonstrated. The researchers described how multicolor quantum dots linked to antibodies can distinguish the Reed-Sternberg cells that are characteristic of Hodgkin's lymphoma. "Our multicolor quantum dot staining method provides rapid detection and identification of rare malignant cells from heterogenous tissue specimens," says senior author Shuming Nie, PhD, the Wallace H. Coulter distinguished professor in the Coulter department of biomedical engineering at Georgia Tech and Emory University. "The clinical utility is not limited to Hodgkin's lymphoma but potentially could be extended to detect cancer stem cells, tumor-associated macrophages and other rare cell types." Quantum dots are nanometer-sized semiconductor crystals that have unique chemical and physical properties due to their size and their highly compact structure. Quantum dots can be chemically linked to antibodies, which can detect molecules present on the surfaces or internal parts of cancer cells.
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