Nanotechnology History: A Non-technical Primer

Earlier an article on history of nanotechnology http://nanosciencetech.blogspot.com/2008/08/history-of-nanotechnology_11.html was published. In this article of Adam Keiper MD, The New Atlantis, few more points are elaborated.

Today, in the young field of nanotechnology, scientists and engineers are taking control of atoms and molecules individually, manipulating them and putting them to use with an extraordinary degree of precision. Word of the promise of nanotechnology is spreading rapidly, and the air is thick with news of nanotech breakthroughs. Governments and businesses are investing billions of dollars in nanotechnology R&D, and political alliances and battle lines are starting to form. Public awareness of nanotech is clearly on the rise, too, partly because references to it are becoming more common in popular culture-with mentions in movies, books, video games, and television.

Yet there remains a great deal of confusion about just what nanotechnology is, both among the ordinary people whose lives will be changed by the new science, and among the policymakers who wittingly or unwittingly will help steer its course. Much of the confusion comes from the name "nanotechnology," which is applied to two different things-that is, to two distinct but related fields of research, one with the potential to improve today's world, the other with the potential to utterly remake or even destroy it. The meaning that nanotechnology holds for our future depends on which definition of the word "nanotechnology" pans out.

From Feynman to Sunscreen

Although a few scientists had done related work earlier, nanotechnology didn't really get going until the second half of the twentieth century. Credit for inspiring nanotechnology usually goes to Richard Feynman, a brilliant Caltech physicist who later won a Nobel Prize for "fundamental work in quantum electrodynamics." In an after-dinner lecture ("There's Plenty of Room at the Bottom") delivered on the evening of December 29, 1959, Feynman proposed work in a field "in which little has been done, but in which an enormous amount can be done in principle."

"What I want to talk about," Feynman said, "is the problem of manipulating and controlling things on a small scale." Feynman described how the entire Encyclopaedia Britannica could be written on the head of a pin, and how all the world's books could fit in a pamphlet. Such remarkable reductions could be done as "a simple reproduction of the original pictures, engravings, and everything else on a small scale without loss of resolution." Yet it was possible to get smaller still: if you converted all the world's books into an efficient computer code instead of just reduced pictures, you could store "all the information that man has carefully accumulated in all the books in the world … in a cube of material one two-hundredth of an inch wide-which is the barest piece of dust that can be made out by the human eye. So there is plenty of room at the bottom!" He declared that "the principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom"-in fact, Feynman saw atomic manipulation as inevitable, "a development which I think cannot be avoided."

Research in the direction Feynman suggested didn't begin immediately, although the next few decades brought sophisticated new tools and techniques for manipulating matter at the atomic level. One early demonstration of this power came in 1990 when a team of IBM physicists revealed that they had, the year before, spelled out the letters "IBM" using 35 individual atoms of xenon. In 1991, the same research team built an "atomic switch," likely to be an important development in the future of computing.

Another breakthrough came with the discovery of new shapes for molecules of carbon, the quintessential element of life. In 1985, researchers reported the discovery of the "buckyball," a lovely round molecule consisting of 60 carbon atoms. This led in turn to the 1991 discovery of a related molecular shape known as the "carbon nanotube"; these nanotubes are about 100 times stronger than steel but just a sixth of the weight, and they have unusual heat and conductivity characteristics that guarantee they will be important to high technology in the coming years.

But these exciting discoveries are the exception rather than the rule: Most of what passes for nanotechnology nowadays is really just materials science. Such "mainstream nanotechnology," as practiced by hundreds of companies spending billions of dollars, is merely the intellectual offspring of conventional chemical engineering and our new nanoscale powers. It is already being incorporated in consumer products: some lines of sunscreens and cosmetics, some stain- and water-repellent clothing, some new paints, a few kinds of anti-reflective and anti-fogging glass, and some tennis equipment. In short, mainstream nanotechnology is an interesting field, with some impressive possibilities for improving our lives with better materials and tools. But that's just half the story: there's another side to nanotechnology, one that promises much more extreme, and perhaps dangerous, changes.

Molecular Manufacturing

This more radical form of nanotechnology originated in the mind of an M.I.T. undergraduate in the mid-1970s. Eric Drexler, who went on to obtain a Ph.D. from M.I.T., realized that the biological "machinery" already responsible for the full diversity of life on Earth could be adapted to build nonliving products upon command. Molecule-sized machines, modeled after those found in nature, could be used to manufacture just about anything man wished.

Drexler, who began to develop these theories even before he'd heard of Feynman's lecture, first published his ideas in a 1981 journal article. Five years later, he brought the notion of molecular manufacturing to the general public with his book Engines of Creation. An astonishingly original work of futurism, Engines of Creation pointed out how molecular manufacturing would revolutionize other areas of science and technology-leading to breakthroughs in medicine, artificial intelligence, and the conquest of space. Drexler refutes every technical objection he can anticipate, explaining how such phenomena as quantum uncertainty and thermal vibrations don't make molecular manufacturing impossible. It was also in Engines that Drexler introduced the term "nanotechnology"-a reference to the nanometer, one-billionth of a meter-to describe this approach to molecular manufacturing, although the term is now also used for the more mundane applications (cosmetics, tennis balls, etc.) described above.

To shore up his technical arguments for the feasibility of his vision, Drexler further expanded on his ideas in the world's first nanotechnology textbook. Nanosystems (1992), a dense volume that grew out of a class he taught at Stanford, is crammed with equations and diagrams and designs for molecular machines, and it has gone far to put the theory of molecular manufacturing on sound technical footing-although scientific debate about the achievability and the best routes to developing nanotechnology has continued.

In the past decade, theorists have begun to flesh out the details of how nanotechnology might be used in manufacturing and medicine, although it is unclear how soon any of this will be possible. Some analysts have estimated that major breakthroughs in molecular manufacturing are at least three decades away; others have suggested that major progress might occur in the next five years.

Controversy and Policy

Since 2000, awareness of nanotechnology among environmental activists, regulators, and lawmakers has been on the rise. Environmental organizations have expressed fears about the potential ecological and health consequences of mainstream nanotechnology, and have called for increased research into safety of nanoparticles.

The Drexler version of advanced nanotechnology has also been the subject of public fear, largely centered on the notion that nanotechnology could spiral out of control and convert all life on Earth into "gray goo." Drexler, who originally introduced this apocalyptic prospect in Engines of Creation, has since repeatedly distanced himself from it-but gray goo retains its grip on the public imagination.

There are other serious reasons to be worried about the development of nanotechnology, including the risk of severe economic disruption; the possibly dehumanizing effects of using nanotechnology on ourselves; and the potential criminal, military, or terrorist use of advanced nanotechnology. A few organizations are paying full-time attention to these concerns, including the Foresight Institute (established in 1986) and the Center for Responsible Nanotechnology (established in 2002).

Public policy discussions have barely begun to reflect those long-term concerns. Although some agencies in the U.S. government have been involved in nanotechnology since the 1980s, federal funding of nanotechnology research did not begin in earnest until the late 1990s. In 2000, the National Nanotechnology Initiative was established to coordinate the government's work in nanotechnology; soon, federal spending on nanotechnology is scheduled to cross the $1 billion-per-year mark. Along with the increased funding has come a government commitment to investigate the "social, economic, health, and environmental implications" of nanotechnology. As public interest continues to grow, and as scientific progress make advanced nanotechnology seem ever more attainable, policymakers are likely to increasingly turn their attentions to the promise and peril of nanotechnology.

Real-Time Observation of Nanowire Anode to Improve Lithium Batteries - World's Smallest Battery

A benchtop version of the world's smallest battery has been created by a team led by Sandia National Laboratories researcher. The anode of this battery is a single nanowire which is claimed to be one seven-thousandth the thickness of a human hair.

To better study the anode's characteristics, the tiny rechargeable lithium-based battery was formed inside a transmission electron microscope (TEM) at the Center for Integrated Nanotechnologies (CINT), a Department of Energy research facility jointly operated by Sandia and Los Alamos national laboratories.

This experiment facilitates the researchers to study the charging and discharging of a battery in real time and at atomic scale resolution, so that they can understand the fundamental mechanism how batteries work.

The motivation behind this work lies in the fact that current lithium ion batteries have very important application but cannot meet the demand due their low power and energy density. To improve performance they need to be investigated from the bottom up; and TEM could bring new insights to the problem.

As nanowire-based materials in lithium ion batteries significantly improved in power and energy density over bulk electrodes, more stringent investigations of their operating properties should improve new generations of plug-in hybrid electric vehicles, laptops and cell phones.

Battery research groups do use nanomaterials as anodes, but in bulk rather than individually -- a process, Scientist Huang says, that resembles "looking at a forest and trying to understand the behavior of an individual tree."

The tiny battery consists of a single tin oxide nanowire anode 100 nanometers in diameter and 10 micrometers long, a bulk lithium cobalt oxide cathode three millimeters long, and an ionic liquid electrolyte. The device offers the ability to directly observe change in atomic structure during charging and discharging of the individual wires.

An unexpected find of the researchers was that the tin oxide nanowire rod nearly doubles in length during charging which is far more than its diameter increases -- a fact that could help avoid short circuits that may shorten battery life. In future manufacturers should take account of this elongation in their battery design.

Huang's group found this flaw by following the progression of the lithium ions as they travel along the nanowire and create what researchers described as "Medusa front" defined by an area where high density of mobile dislocations cause the nanowire to bend and wiggle as the front progresses. The web of dislocations is caused by lithium penetration of the crystalline lattice. These observations prove that nanowires can sustain large stress (>10 GPa) induced by lithiation without breaking; a clear indicating that these nanowires are very good candidates for battery electrodes.

Lithiation-induced volume expansion, plasticity and pulverization of electrode materials are the major mechanical defects that plague the performance and lifetime of high-capacity anodes in lithium-ion batteries. So these observations of structural kinetics and amorphization have important implications for high-energy battery design and in mitigating battery failure.

Researchers estimated a current level of a picoampere flowing in the nanowire during charging and discharging.

Although the work was carried out using tin oxide (SnO2) nanowires, the experiments can be extended to other materials systems, either for cathode or anode studies.

The methodology that was developed should stimulate extensive real-time studies of the microscopic processes in batteries and lead to a more complete understanding of the mechanisms governing battery performance and reliability.

A report on an Advancement of IBM on its CMOS Nanophotonics

IBM announced significant advances in its path to integrate electrical and optical devices on the same piece of silicon. The new CMOS Integrated Silicon Nanophotonics, which is the result of a decade of development at IBM's global Research laboratories, promises over 10 times improvement in integration density than is feasible with current manufacturing techniques.

IBM said it anticipates that Silicon Nanophotonics will dramatically increase the speed and performance between chips. In addition to combining electrical and optical devices on a single chip, the new IBM technology can be produced on the front-end of a standard CMOS manufacturing line. Transistors can share the same silicon layer with silicon nanophotonics devices. To make this approach possible, IBM researchers have developed a suite of integrated ultra-compact active and passive silicon nanophotonics devices that are all scaled down to the diffraction limit defined by the smallest size that dielectric optics can afford. This makes possible the integration of modulators, germanium photodetectors and ultra-compact wavelength-division multiplexers with high-performance analog and digital CMOS circuitry.

"The development of the Silicon Nanophotonics technology brings the vision of on-chip optical interconnections much closer to reality,” said vice president, Science and Technology, IBM Research. “With optical communications embedded into the processor chips, the prospect of building power-efficient computer systems with performance at the Exaflop level is one step closer to reality."

This CMOS Integrated Nanophotonics breakthrough preedicts unprecedented increases in silicon chip function and performance via ubiquitous low-power optical communications between racks, modules, chips or even within a single chip itself. The next step in this advancement is to establishing manufacturability of this process in a commercial foundry using IBM deeply scaled CMOS processes.

IBM has been pursuing an ambitious Exascale computing program, which is aimed at developing a supercomputer that can perform one million trillion calculations—or an Exaflop in a single second.

A Govt of India Initiative on Nanotechnology

This TWO day event is featuring top global intellects, entrepreneurs and organizations in the field of Nanotechnology.

The 3rd edition of Bangalore Nano organized by The Department of IT, BT and S&T, Government of Karnataka under the guidance of Vision Group on Nanotechnology was inaugurated today at the Lalit Ashok. The focal theme of Bangalore Nano 2010 is “Frontiers of Nanotechnology: Impact on India. This TWO day event is featuring top global intellects, entrepreneurs and organizations in the field of Nanotechnology.

The opening plenary session titled “Nanotechnology: A Key Tool in Attaining Developmental Goals – Part II” Chairing the session on the first day at 3rd Bangalore Nano, Dr Amit Biswas, Head- Technology Services & emerging Technologies at Reliance Industries Ltd, said, “ Nano technology is emerging as an industry and it can impact several industries from Healthcare to Defence..” Other panelists at the session were Dr. W. Selvamurthy, Chief Controller, R&D, DRDO and Dr. M K Bhan, Secretary, Department of Biotechnology, Govt of India.

Dr W. Selvamurthy, Chief Controller, R&D, DRDO, said, “Nano technology has several applications from agriculture to Defence. So far, academic institutions are working as islands of excellence and they need to work like a continent of excellence. A research in one specialization need not be limited to applications in that specialization. That can contribute a lot in totally different sectors. For example the breakthroughs in various labs under DRDO are not only enhancing the capabilities of Indian Armed Forces, But also contributing to the businesses and public outside the purview of the defence. DRDO has invested Rs. 200 crores exclusively for the nano technology applications. These applications will enhance strength and capabilities of missiles. These outcomes are also highly useful to churn out products in healthcare, medicine, sensors, and energy harvesting.”

Dr. Selvamurthy announced, “DRDO is planning to set up a nano foundry by investing Rs. 500 to Rs. 600 crores. This project will be a cluster with the partnering of IITs and other academic institutions of India. The R&D facilities for nano technology can be used by industry and academic institutions for research purpose. Moreover, DRDO will also fund nano research at the academic institutions.”

Dr. Selvamurthy added, “One of the Labs of DRDO is exclusively working on safety of nanotechnology for individual and environment. Nanocomposite coatings developed by Ahmednagar lab will find uses in several anti corrosive industrial applications. Defence Bioengineering and Electromedical lab of DRDO at Bangalore is developing several biosensors that ensure safety of the soldier in the warfare and those applications can revolutionise medical diagnostics. Very soon, CIPLA is going to take up the production of nano particle drugs that can be directly deposited into lungs, which was originally developed for the soldiers at high altitudes.”

Dr M K Bhan, Secretary, Department of Biotechnology, Govt of India, said, “Strong scientific force, technology innovation, and product innovation are needed for the nano industry to flourish in India. We need drivers of innovation and regulation to produce nano champions in the fields of agriculture and healthcare. We should create industry platforms, which will decide where to apply nanotechnology. Biomarkers and biodiagnostics can revolutionise the diagnostic industry. For example, high sensitivity detection methods that can trace very low quantities in saliva can actually detect alzheimers disease, which otherwise needs brain tissue. Food packaging industry is another nascent industry in India, which can do wonders on the back of nano technology. Similarly, low cost health screening technologies can boost public health.”

Cleans Water with Nanotechnology

A new water filter developed in South Africa could provide millions of people with clean drinking water. The filter, about the size and shape of a teabag, would be inexpensive, easy to distribute and simple to use.

Researchers are conducting a final set of tests on a new type of diminutive water filter before industrial production can begin. The microbiologist pours water from a plastic bottle though a high-tech, teabag-sized filter before analyzing it in laboratory at the University of Stellenbosch in South Africa. The filter would be much cheaper than bottled water as well as any other filter on the market. Instead of being filled with black or green tea, the bag contains active carbon granules and is made from nanofibers treated with biocide, which kills bacteria rather than simply filtering them from the water.

This project takes nanotechnology to the poorest of the poor people who live in this world, and it will make a difference in their lives. With some 300 million people in Africa - and over a billion worldwide - living without access to clean drinking water, the need for such a filter is huge. When in mass production, the developers said they expect the teabag to cost just a few South African cents (under half a US cent and under a third of a euro cent).

In addition to being inexpensive the filter is also easy to distribute to rural area and simple to use as it can be placed in an adapter that fits on nearly any regular-sized plastic bottle. Each filter can clean one liter (one quart) of the most polluted water to the point where it is completely safe to drink. Once used, the filter can be disposed of and is biodegradable.

African countries, led by Somalia, Mauritania and Sudan, were ranked to have the most vulnerable water supplies, according to a June report by UK-based risk consultancy firm Maplecroft.

It is simply impossible to build purification infrastructure at every polluted stream. So this filter has taken the solution right at the the people. The water is cleaned right then and there when people drink. The filter is now undergoing testing by the South African Bureau of Standards, after which it can be rolled out to the United Nations and non-governmental organizations that have expressed interest in it.

Advanced Nanogenerators for Versatile Applications

In the last article (http://nanosciencetech.blogspot.com/2010/11/self-powered-nanosensors-based-on-zinc.html) we have discussed about the nano generators basically based on the movement of the zinc oxide nanowires resulting the necessary piezoelectric effect to produce small amount of electricity. This technology can be very much utile in medical sciences, where there is a growing need for the surgery less equipments and supporting technology.

In a recent development, researchers have come up with a technique where they use the freely bendable piezoelectric ceramic thin film nano-materials that can convert tiny movements of the human body (such as heart beats and blood flow) into electrical energy. Thus these devices can be implanted in micro robot which can operate human organs without their battery charged.

The ceramics, containing a perovskite structure, have a high piezoelectric efficiency. Until now, it has been very difficult to use these ceramic materials to fabricate flexible electronic systems due to their brittle property. The research team, however, has succeeded in developing a bio-eco-friendly ceramic thin film nanogenerator that is freely bendable without breakdown.

Nanogenerator technology, a power generating system without wires or batteries, combines nanotechnology with piezoelectrics that can be used not only in personal mobile electronics but also in bio-implantable sensors or as an energy source for micro robots. Energy sources in nature (wind, vibration, and sound) and biomechanical forces produced by the human body (heart beats, blood flow, and muscle contraction/relaxation) can infinitely produce nonpolluting energy.

This technology can be used to turn on an LED by slightly modifying circuits and operate touchable flexible displays. In addition, thin film nano-materials have the property of both high efficiency and lead-free bio compatibility, which can be used in future medical applications.

Self-Powered Nanosensors Based on Zinc Oxide Nanowires

Researchers have created first self-powered nanometer-scale sensing devices by combining a new generation of piezoelectric nanogenerators with two types of nanowire sensors. The new devices can measure the pH of liquids or detect the presence of ultraviolet light using electrical current produced from mechanical energy in the environment.

Based on arrays containing as many as 20,000 zinc oxide nanowires in each nanogenerator, the devices can produce up to 1.2 volts of output voltage, and are fabricated with a chemical process designed to facilitate low-cost manufacture on flexible substrates. Tests done with nearly one thousand nanogenerators -- which have no mechanical moving parts -- showed that they can be operated over time without loss of generating capacity.

The report said that the nanoscale generators, which use the piezoelectric effects, produces electric charges when wires made from zinc oxides are subjected to strain. The strain can be produced by simply flexing the wires. The total current from many wires can be added up to power small devices. The research effort has recently focused on increasing the amount of current and voltage generated and on making the devices more robust.

The zinc oxide nanowires are embedded at the both ends of them in a polymer substrate. As they are compressed in a flexible nanogenerator enclosure, they can then generate current. That eliminates the need of metallic electrode that was required in earlier devices. Because the generators are completely enclosed, they can be used in a variety of environments. The whole system thus can be grown on folded and flexible substrates with temperatures of less than100 degrees Celsius. That will accord lower cost fabrication and growth on just about any substrate.

The nanogenerators are produced using a multi-step process that includes fabrication of electrodes that provide both ohmic and shottky contacts for the nanowires. The arrays can be grown both vertically and laterally. To maximize current and voltage, the growth and assembly requires alignment of crystalline growth, as well as the synchronization of charging and discharging cycles.

Production of vertical nanogenerators begins with growing zinc oxide nanowires on a gold-coated surface using a wet chemical method. A layer of polymethyl-methacrylate is then spun-coated onto the nanowires, covering them from top to bottom. Oxygen plasma etching is then performed, leaving clean tips on which a piece of silicon wafer coated with platinum is placed. The coated silicon provides a Shottky barrier, which is essential for maintaining electrical current flow.

The alternating current output of the nanogenerators depends on the amount of strain applied. At a strain rate of less than two percent per second, 1.2 volts is the produced output voltage. Lateral nanogenerators integrating 700 rows of zinc oxide nanowires produced a peak voltage of 1.26 volts at a strain of 0.19 percent. In a separate nanogenerator, vertical integration of three layers of zinc oxide nanowire arrays produced a peak power density of 2.7 milliwatts per cubic centimeter. By measuring the amplitude of voltage changes across the device when exposed to different liquids, the pH sensor can measure the acidity of liquids. An ultraviolet nanosensor depends on similar voltage changes to detect when it is struck by ultraviolet light.

The new generator and nanoscale sensors open new possibilities for very small sensing devices that can operate without batteries, powered by mechanical energy harvested from the environment. Energy sources could include the motion of tides, sonic waves, mechanical vibration, the flapping of a flag in the wind, pressure from shoes of a hiker or the movement of clothing.

Spiderman suit based on nanotechnology

Imagine owning your own Spiderman suit, complete with gloves and boots to allow you to stick to walls, and even a sticky silk spinner to swing between buildings. That might be a step closer to reality, thanks to Nicola Pugno at the Polytechnic University of Turin in Italy, who has come up with a scheme for an adhesive material and “spider silk” based on carbon nanotubes.

Efforts to develop surface gripping materials have focused on mimicking geckos, which can hang upside down from just one toe because their feet are covered with millions of tiny elastic hairs called setae. Each seta is attracted to the wall, largely by an intermolecular force called the van der Waals force, allowing the gecko’s feet to adhere.

Researchers have previously created nanotechnology structures – carbon nanotubes – that mimic setae, but though these have around 200 times the adhesive force of gecko feet, they have yet to be scaled up to a size fit for superheroes. That’s because if you simply make the nanotubes longer, they become floppy and stick to each other rather than to the wall. On the other hand, if you make them fatter and stiffer, they become too inflexible to ensure a large enough contact area with the wall.

Now, in a paper to be published in Journal of Physics: Condensed Matter, Pugno suggests that the secret to developing an effective sticky material lies in creating a “hierarchical structure” – branching bristles of ever finer nanotubes, just as the setae of a gecko’s feet are divided at their ends into smaller branches called spatulae. Pugno calculates that this approach could result in stiff, non-tangling structures with tips still flexible enough to produce good adhesion.

Researchers at Rensselaer Polytechnic Institute in Troy, New York, have previously built similar branched nanotube structures by growing them inside aluminium oxide templates.

That just leaves the problem of swinging between buildings on Spiderman-style silk. Researchers can already spin metre-long carbon nanotube fibres (Strong, Transparent, Multifunctional, Carbon Nanotube Sheets), and much longer ones should be possible, so Pugno proposes making a cable consisting of around 4 million nanotube fibres.

Each nanotube is invisible, as they are much thinner than the wavelength of light. It is suggested that suggests that by anchoring the nanotubes through holes in a 1-centimetre-square spacer plate to keep the fibres 5 micrometres apart, the whole cable would remain invisible. The end of each fibre passing through the plate could be branched to create the seta structure, allowing it to stick to the target surface. Then all you would need to do is fire the cable from some kind of launcher device.

Stefano Mezzasalma at the University of Trieste in Italy says the approach could work. “The first prototype of a Spiderman suit might be ready in a decade or so.”

Microparticles Can Be Captured

To trap and hold tiny microparticles, engineers at Harvard have "put a ring on it," using a silicon-based circular resonator to confine particles stably for up to several minutes.

“We demonstrated the power of what we call resonant cavity trapping, where a particle is guided along a small waveguide and then pulled onto a micro-ring resonator," explains Kenneth Crozier, an Associate Professor of Electrical Engineering at the Harvard School of Engineering and Applied Sciences (SEAS) who directed the research. "Once on the ring, optical forces prevent it from escaping, and cause it to revolve around it."

The process looks similar to what you see in liquid motion toys, where tiny beads of colored drops run along plastic tracks -- but on much smaller scale and with different physical mechanisms. The rings have radii of a mere 5 to 10 micrometers and are built using electron beam lithography and reactive ion etching.

Specifically, laser light is focused into a waveguide. Optical forces cause a particle to be drawn down toward the waveguide, and pushed along it. When the particle approaches a ring fabricated close to the waveguide, it is pulled from the waveguide to the ring by optical forces. The particle then circulates around the ring, propelled by optical forces at velocities of several hundred micrometers-per-second.

While using planar ring resonators to trap particles is not new, Crozier and his colleagues offered a new and more thorough analysis of the technique. In particular, they showed that using the silicon ring results in optical force enhancement (5 to 8 times versus the straight waveguide).

"Excitingly, particle-tracking measurements with a high speed camera reveal that the large transverse forces stably localize the particle so that the standard deviation in its trajectory, compared to a circle, is as small as 50 nm," says Crozier. "This represents a very tight localization over a comparatively large distance."

The ultimate aim is to develop and demonstrate fully all-optical on chip manipulation that offers a way to guide, store, and deliver both biological and artificial particles.

Sandful lotion!

South Australian researchers have invented and patented a new technology which can deliver the cosmetics and drugs to the skin. They are using nanoparticles of silica (usually sand) to create longer lasting cosmetics and creams that control the delivery of drugs through the skin.

They already have a family of international patents on their technology, and are now actively looking for commercial partners to get their invention out of the lab and on to your skin.

It has been reported from Wark Research Institute that they are using nanoparticles silica to create the emulsions on which the emulsions on which many cosmetics and therapeutic products are based.

The work is being presented for the first time in public through Fresh Science, a communication boot camp for early-career scientists held at the Melbourne Museum. They have developed emulsions in which silica nanoparticles coat the oil droplets. Coating the tiny emulsion droplets with silica increases the stability of the mixture, and makes it less likely that the active compounds inside will degrade or be released until scientists want to do so.

Thus using this method drug delivery can be controlled by adjusting release through the thickness of the coating. This could be really beneficial if a drug has to be released at a specific time, or if releasing too much at once can lead to accumulation and toxic effects.

According to the researcher silica nanoparticles interact with skin cells in a way which increases the delivery of drugs to specific skin layers significantly. Using the nanoparticles, not only was a higher concentration of the active ingredient delivered, but also leakage into the blood stream was limited. This is a great advantage for skin creams. It limits exposure of the rest of the body, and any consequent toxicity.

On the other hand nanoparticle-coated emulsions are cost-effective, because they are efficient at delivering drugs. A smaller quantity of active compound can be used in a more stable form.

Water could be the key to cheaper nanoelectronics!

Previously we saw that water could play a role in enhancing the density of memory storage devices. (http://nanosciencetech.blogspot.com/2008/11/ultra-dense-memory-storage-devices.html).

Now a recent study at the Kavli Institute of Nanoscience in DELFT, Netherlands shows that a splash of the wet stuff could help make nanoelectronic manufacturing both quicker and cheaper.

Now days, nanoscale components are embedded in the electronic circuit boards, but they are very difficult and they require superior level of accuracy. To get complicated nanostructures nanostructures on a silicon chip it is sometimes necessary to grow them in separate layers and then transfer these one by one onto the final chip (PDF) to build them into working components.

Often it takes strong chemicals to separate the layers from the surface on which they are grown, and high temperatures may be needed to activate the thermal adhesives that keep the components in place at their destination.

Researchers have found a way to use water to transfer layers quickly and easily from one surface to another. They exploit the fact that different materials have different hydrophilicity defined by the tendency to attract water through transient hydrogen bonds.

The team took a relatively hydrophilic silicon wafer onto which a graphene structure had been deposited in the desired pattern. Then they dipped it into a solution containing a hydrophobic polymer that dried to form a strong, solid hydrophobic layer on top of the wafer.

Next, they submerged the silicon wafer in water. Because graphene is equally hydrophobic, the water molecules wiped out both layers out of the way to wet the hydrophilic silicon beneath it, gradually "wedging" them off the silicon base. The polymer-graphene film then floated to the surface of the water.

Now the team placed a second silicon wafer beneath the floating film and used a needle to prod the film into position before draining away the water. Intermolecular forces between the graphene and silicon then provide a surprisingly stable attachment.

They then dissolved away the hydrophobic polymer to leave the graphene attached to the new wafer. Repeating the technique several times would allow graphene layers to be built up into a complex electronic nanostructure.

WANDA: Reducing the Human Error!

Berkeley Lab scientists have established a revolutionary nanocrystal-making robot, capable of producing nanocrystals with extreme precision. This one-of-a-kind robot provides colloidal nanocrystals with custom-made properties for electronics, biological labeling and luminescent devices.

This robotic engineer is named WANDA (Workstation for Automated Nanomaterial Discovery and Analysis) and was developed in collaboration with Symyx Technologies at the Molecular Foundry, a U.S. Department of Energy User Facility located at Berkeley Lab. By automating the synthesis of these nanocrystals, WANDA overcomes the issues facing traditional techniques, which can be laborious and are difficult to reproduce from one laboratory to the next. What's more, WANDA's synthetic prowess can help researchers sift through a large, diverse pool of materials for specific applications. Such a combinatorial approach has been used for decades in the pharmaceutical industry and now is being applied to nanomaterials at the Foundry.

WANDA makes nanocrystals of exceptional quality - every time - optimized for different applications. It can also be used to discover new nanocrystal compositions with advantageous properties.

WANDA's liquid-handling robotics prepares and initiates reactions by injecting nanocrystal precursor chemicals into an array of reactors. After a series of reactions is complete, the structural and optical properties of these nanocrystals can be screened rapidly, also using automated methods. WANDA is kept inside a nitrogen-filled chamber, designed to keep oxygen and water from interacting with reactive precursor chemicals and freshly formed nanocrystals. Since this robot is controlled by software protocols, novice users can direct WANDA to perform complex workflows that traditionally require extensive chemistry experience.

Scientists have directed WANDA to produce and optimize a diverse set of nanomaterials under conditions analogous to those employed in traditional flask-based chemistry. Starting with widely studied and practically useful nanomaterials; such as cadmium selenide quantum dots, whose size can be adjusted to emit different colors of visible light. Scientists showed how WANDA can optimize the size, crystal structure and luminescence properties of different nanocrystals.

Scientists are expecting a revolutionary change in the way nanoscience research is performed. Not only does WANDA enable the optimization and mass production of nanoparticles users need, but this robot also facilitates experiments that give us a deeper understanding into the chemistry and physics of nanoscale materials.

Lithium Ion Batteries Boosted by Nanocomposites

Nanocomposites aim to boost the capacity of lithium ion batteries by five-times by hanging nanometer-sized silicon particles on trees of carbon black that self-assemble into porous micron-sized spheres, which increase an electrode's surface area with interconnected internal channels.

High-performance lithium ion batteries today use anodes made from carbon (graphite). Silicon has been proposed as a substitute for graphite since it offers a theoretical improvement of 10-times in capacity over graphite, but so far prototypes have proven too unstable for creating lithium batteries with a long lifetime.

The problem is that silicon particles crack when they are formed at the same granularity of graphite particles—about 15 to 20 microns. The new nanocomposite material solves that problem by hanging 30 nanometer sized silicon particles on trees of carbon black which then self-assemble into porous spheres about 10-to-30 microns in diameter. The resulting electrode remains stable due to the durable carbon-superstructure that prevents cracking, but benefits from the increased surface area afforded by the smaller silicon nanoparticles.

Common chemical vapor deposition processes allow the new hybrid silicon-carbon electrodes to be mass produced economically. As the tiny silicon nanoparticles are permanently attached to the micron-sized carbon black trees, they avoid the health hazards of processes that require handling of nanoscale particles.

So far Georgia Tech has fabricated experimental anode electrodes, which it is testing for use in standard manufacturing processes for lithium batteries. Their prototype has survived over one hundred recharge cycles without any degradation, leading the researchers to predict they will last for thousands of recharges.

Silicon Technology For Medical Application

A team of cardiologists, materials scientists, and bioengineers have created and tested a new type of implantable device for measuring the heart's electrical output that they say is a vast improvement over current devices. The new device represents the first use of flexible silicon technology for a medical application.

This technology may herald a new generation of active, flexible, implantable devices for applications in many areas of the body, commented Brian Litt, an associate professor of Neurology at the University Of Pennsylvania School Of Medicine and also an associate professor of Bioengineering in Penn's School of Engineering and Applied Science.

Implantable silicon-based devices have the potential to serve as tools for mapping and treating epileptic seizures, providing more precise control over deep brain stimulation, as well as other neurological applications, say Story Landis, PhD, director of the National Institute of Neurological Disorders and Stroke, which provided support for the study.

The new devices bring electronic circuits right to the tissue, rather than having them located remotely, inside a sealed can that is placed elsewhere in the body, such as under the collar bone or in the abdomen, explained Litt. This enables the devices to process signals right at the tissues, which allows them to have a much higher number of electrodes for sensing or stimulation than is currently possible in medical devices.

Now, for example, devices for mapping and eliminating life-threatening heart rhythms allow for up to 10 wires in a catheter that is moved in and around the heart, and is connected to rigid silicon circuits distant from the target tissue. This design limits the complexity and resolution of devices since the electronics cannot get wet or touch the target tissue.

The team tested the new devices - made of nanoscale, flexible ribbons of silicon embedded with 288 electrodes, forming a lattice-like array of hundreds of connections - on the heart of a porcine animal model. The tissue-hugging shape allows for measuring electrical activity with greater resolution in time and space. The new device can also operate when immersed in the body's salty fluids. The devices can collect large amounts of data from the body, at high speed. This allowed the researchers to map electrical activity on the heart of the large animal.

In this experiment, the researchers built a device to map waves of electrical activity in the heart of a large animal. The device uses the 288 contacts and more than 2,000 transistors spaced closely together, while standard clinical systems usually use about five to 10 contacts and no active transistors. High-density maps of electrical activity on the heart were recorded from the device, during both natural and paced beats.

Scientists are also planning to design advanced, intelligent pacemakers that can improve the pumping function of hearts weakened by heart attacks and other diseases. For each of these applications, the team is conducting experiments to test flexible devices in animals before starting human trials.

Another focus of ongoing work is to develop similar types of devices that are not only flexible, like a sheet of plastic, but fully stretchable, like a rubber band. The ability to fully conform and wrap around large areas of curved tissues will require stretch ability, as well as flexibility.

About Soft Interference Lithography (SIL)

Researchers at Northwestern University had developed a nano manufacturing technique (2007) which can be used to produce nanostructures measuring tens of square centimeters. This new technique, dubbed ‘soft interference lithography’ (SIL), can lead to nanomaterials with optical properties mimicking some metamaterials in the natural world such as peacock feathers and butterfly wings. As said the researchers, their SIL technique combines the ability of interference lithography to produce wafer-scale nanopatterns with the versatility of soft lithography and used it to create plasmonic metamaterials.

Here is how scientists described SIL. “The optical nanomaterials in this research are called ‘plasmonic metamaterials’ because their unique physical properties originate from shape and structure rather than material composition only. Two examples of metamaterials in the natural world are peacock feathers and butterfly wings. Their brightly colored patterns are due to structural variations at the hundreds of nanometers level, which cause them to absorb or reflect light. Through the development of a new nanomanufacturing technique, researchers succeeded in making gold films with virtually infinite arrays of perforations as small as 100 nanometers — 500-1000 times smaller than a human hair. On a magnified scale, these perforated gold films look like Swiss cheese except the perforations are well-ordered and can spread over macroscale distances. The researchers’ ability to make these optical metamaterials inexpensively and on large wafers or sheets is what sets this work apart from other techniques.”

In the research section of her site, Mrs. Odom describes plasmonic materials and their optical properties. “Plasmonics is an exciting and emerging area that uses metal nanostructures to manipulate light on the nanoscale. Depending on their size, shape, and materials properties, noble metal nanoparticles can scatter and absorb light to produce colors ranging from the ultra-violet to the near-infrared. In addition, significantly more light can be transmitted through metal films perforated with subwavelength hole arrays than is permitted by geometric optics, a phenomena known as enhanced optical transmission.”

And she gives some additional details. “We focus primarily on the optical properties of two different but complementary systems that can control light on the nanometer scale: (i) metallic films of nanohole arrays and (ii) pyramidal nanoparticles. The former have properties dominated by SPPs, and the latter have properties dominated by LSPs. Such nanostructures are easily made by our innovative fabrication scheme, PEEL, for preparing large-area, free-standing films of nanoscale holes and particles. PEEL is a simple procedure which combines Phase-shifting photolithography, Etching, Electron-beam deposition, and Lift-off of the metal film.”

RAPID: A NEW NANOFABRICATION PROCESS

For exploring the full potentiality of nanotechnology and its sea like vast application in elctronics and hardware industry, the ability to create tiny patterns is important. They are extremely important for fabrication of computer chips and many other application. Yet, creating ever smaller features, through a widely-used process called photolithography, has required the use of ultraviolet light, which is difficult and expensive to work with. John Fourkas, Professor of Chemistry and Biochemistry in the University of Maryland College of Chemical and Life Sciences, and his research group have developed a new, table-top technique called RAPID (Resolution Augmentation through Photo-Induced Deactivation) lithography that makes it possible to create small features without the use of ultraviolet light. Photolithography uses light to deposit or remove material and create patterns on a surface. There is usually a direct relationship between the wavelength of light used and the feature size created. Therefore, nanofabrication has depended on short wavelength ultraviolet light to generate ever smaller features.

The RAPID lithography technique have been developed to create patterns twenty times smaller than the wavelength of light employed; by this process it streamlines the nanofabrication process. That’s how RAPID can be used in many applications in areas such as electronics, optics, and biomedical devices.

In this process, two laser lights of same color have been used for controlling the operation. First, short burst of light used to harden the material and secondly, a constant light source used to prevent it. The technique has been highly appreciated for its easiness to implement, as there is no need to control the timing between two different pulsed lasers.

Cold atoms could replace hot gallium in focused ion beams

Scientists at the National Institute of Standards and Technology (NIST) have developed a radical new method of focusing a stream of ions into a point as small as one nanometer (one billionth of a meter). Because of the versatility of their approach—it can be used with a wide range of ions tailored to the task at hand—it is expected to have broad application in nanotechnology both for carving smaller features on semiconductors than now are possible and for nondestructive imaging of nanoscale structures with finer resolution than currently possible with electron microscopes. Researchers and manufacturers routinely use intense, focused beams of ions to carve nanometer-sized features into a wide variety of targets. In principle, ion beams also could produce better images of nanoscale surface features than conventional electron microscopy. But the current technology for both applications is problematic. In the most widely used method, a metal-coated needle generates a narrowly focused beam of gallium ions. The high energies needed to focus gallium for milling tasks end up burying small amounts in the sample, contaminating the material. And because gallium ions are so heavy, if used to collect images they inadvertently damage the sample, blasting away some of its surface while it is being observed. Researchers have tried using other types of ions but were unable to produce the brightness or intensity necessary for the ion beam to cut into most materials.

The NIST team took a completely different approach to generating a focused ion beam that opens up the possibility for use of non-contaminating elements. Instead of starting with a sharp metal point, they generate a small "cloud" of atoms and then combine magnetic fields with laser light to trap and cool these atoms to extremely low temperatures. Another laser is used to ionize the atoms, and the charged particles are accelerated through a small hole to create a small but energetic beam of ions. Researchers have named the groundbreaking device "MOTIS," for Magneto-Optical Trap Ion Source.

Because the lasers cool the atoms to a very low temperature, they're not moving around in random directions very much. As a result, when ions are accelerated, they travel in a highly parallel beam, which is necessary for focusing them down to a very small spot, explains Jabez McClelland of the NIST Center for Nanoscale Science and Technology. The team was able to measure the tiny spread of the beam and show that it was indeed small enough to allow the beam to be focused to a spot size less than 1 nanometer. The initial demonstration used chromium atoms, establishing that other elements besides gallium can achieve the brightness and intensity to work as a focused ion beam .

JUNCTIONLESS TRANSISTORS!

From the early ages of transistors i.e. in 1940s when they were over 1 centimeter size to the modern age where transistors are less than 30 nanometers long – transistors are shrinking their size over three thousands times. The outcome is that more transistor based circuits are integrated into a single chip. But this development cannot continue for much longer. One of the increasingly difficult problems that chip designers are facing is that the high density of components packed on a chip makes interconnections increasingly difficult; and, as conventional chip structures continue to shrink, Moore's Law is on a collision course with the laws of physics.

All existing transistors are based on junctions – obtained by changing the polarity of silicon from positive to negative. It is a little bit like changing the color of silicon from black to white, explains Jean-Pierre Colinge, a professor at Tyndall National Institute, whose team has just reported a breakthrough in nanoelectronics by demonstrating the world's first junctionless transistor.

In modern transistors, a negative-positive-negative structure needs to be created, where the width of the positive region is only a few dozens of atoms wide.

In a junctionless gated transistor the doping concentration in the channel is identical to that in the source and drain. Because the gradient of the doping concentration between source and channel or drain and channel is zero, no diffusion can take place, which eliminates the need for costly ultrafast annealing techniques and allows one to fabricate devices with shorter channels.

The devices have full CMOS functionality, but they contain no junctions or doping gradients and are, therefore, much less sensitive to thermal budget issues than regular CMOS devices.

The key to fabricating a junctionless gated transistor is the formation of a semiconductor layer that is thin and narrow enough to allow for full depletion of carriers when the device is turned off. The semiconductor also needs to be heavily doped to allow for a reasonable amount of current flow when the device is turned on. Putting these two constraints together imposes the use of nanoscale dimensions and high doping concentrations.

The electrical current flows in this silicon nanowire, and the flow of current is perfectly controlled by a wedding ring structure that electrically squeezes the silicon wire. These structures are easy to fabricate even on a miniature scale which leads to the major breakthrough in potential cost reduction.

Germanium Nanoelectronics

In the world of miniaturization we are always thinking of faster and smaller things. The use of germanium instead of silicon as primary material of transistor would provide us smaller transistor chip which are faster than its previous counterparts.

During the production of transistor, foreign atoms such as phosphorus and boron are implanted into the semiconductor material so that it becomes partly conducting. But this production step damages the material; it must be repaired by subsequent annealing. As the phosphorus atoms are strongly redistributed within the material during annealing, it has not been possible to manufacture large scale integrated transistors using germanium.

Scientists of the research center Forschungszentrum Dresden-Rossendorf (FZD) surmount this problem with two novel techniques.

Germanium was the basic material of first-generation transistors before it was replaced by silicon at the end of the 1960s. This was due to the excellent electronic properties of the interface between the semiconductor silicon and its insulating and passivating oxide. However, this advantage cannot be utilized if transistor dimensions are further reduced since the oxide must then be replaced by so-called high-k dielectrics. This again stimulates science and industry to search for the most suitable basic material. Higher switching speeds could also be achieved using germanium and some other semiconductors.

By inserting foreign atoms the conductivity of semiconductors can be varied in a purposeful way. One possibility is ion implantation (ions are charged atoms) with subsequent heat treatment, which is called annealing. Annealing of the germanium crystal is necessary as the material is heavily damaged during implantation, and leads to the requested electronic properties. While these methods allow for the manufacturing of p-channel transistors (PMOS) according to future technology needs, it was not possible to produce corresponding n-channel transistors (NMOS) using germanium. This is due to the strong spatial redistribution (diffusion) of the phosphorus atoms which have to be used in manufacturing the n+ regions.

Physicists from the FZD applied a special annealing method that enables repairing the germanium crystal and yields good electrical properties without the diffusion of phosphorus atoms. The germanium samples were heated by short light pulses of only a few milliseconds. This period is sufficient in order to restore the crystal quality and to achieve electrical activation of phosphorus, but it is too short for the spatial redistribution of the phosphorus atoms. The light pulses were generated by the flash lamp equipment which was developed at the research center FZD. Analysis of the electrical and structural properties of the thin phosphorus-doped layers in germanium was performed in close collaboration with colleagues from the Belgian microelectronics center IMEC in Leuven and from the Fraunhofer-Center for Nanoelectronic Technologies (CNT) in Dresden.

STRANGE CARBON NANOTUBES!

Carbon nanotubes (CNTs) are 'strange' nanostructures in a sense that they have both high mechanical strength and extreme flexibility. Deforming a carbon nanotube into any shape would not easily break the structure, and it recovers to original morphology in perfect manner. Researchers in China are exploiting this phenomenon by making CNT sponges consisting of a large amount of interconnected nanotubes, thus showing a combination of useful properties such as high porosity, super elasticity, robustness, and little weight (1% of water density).

The nanotube sponges not only show exciting properties as a porous material but they also are very promising to be used practically in a short time. The production method is simple and scalable, the cost is low, and the sponges can find immediate use in many fields related to water purification.

One of the researchers explains that the nanotube sponges are a completely new structure compared with artificial porous materials in several aspects. The sponge is built entirely with nanotubes through a random (yet desired) interconnection. With a high porosity of >99%, the sponge can be compressed to less than 10% of its original volume yet still recover perfectly. Usually, porous materials tend to become brittle at increasing porosity, thus obtaining a material with both high porosity and flexibility has been challenging.

Carbon nanotubes could take advantage of their high surface area and excellent mechanical strength and flexibility. The scientists synthesized the sponges by a chemical vapor deposition (CVD) process during which the CNTs (multi-walled nanotubes with diameters in the range of 30 to 50nm and lengths of tens to hundreds of micrometers,) self-assembled into a porous, interconnected, three-dimensional framework.

The growth process of the sponges is like a consecutive stacking and penetration of numerous CNT 'piles' into centimeter thickness, which is substantially different from aligned arrays where most of CNTs grow continuously from the bottom to top surface or thin sheets where CNTs were densified into a two-dimensional network during vacuum filtration.

According to the scientists, the CNT sponges are capable of absorbing a wide range of solvents and oils with excellent selectivity, recycle ability, and absorption capacities up to 180 times their own weight, two orders of magnitude higher than activated carbon.

The potential application areas for these sponges are vast. They could be used in large-area oil spill clean-ups, water purification and toxic gas filtration. In addition to environmental applications, the CNT sponges can find use as protective coating, thermal insulator, and high strength-to-weight composite. For example, the sponges can absorb mechanical energy during large-strain deformation, therefore resist foreign force or impact. Their high surface area and porosity are also useful for supporting fine catalyst particles in photo-catalytic devices and fuel cells.

NANOCOMPOSITES COULD CHANGE DIABETES TREATMENT

The people who are suffering from diabetes may soon be able to wear contact lenses that continuously alert them to variations in their glucose levels by changing colors. This facility reduces the need to routinely draw blood throughout the day.

The non-invasive technology, developed by Chemical and Biochemical Engineering professor Jin Zhang at The University of Western Ontario, uses extremely small nanoparticles embedded into the hydrogel lenses. These engineered nanoparticles react with glucose molecules found in tears, causing a chemical reaction that changes their color.

Zhang received $216,342 from the Canada Foundation for Innovation (CFI)  to further develop technologies using multifunctional nanocomposites.These technologies have vast potential applications beyond biomedical devices, including for food packaging. For example, nanocomposite films can prevent food spoilage by preventing oxygen, carbon dioxide and moisture from reaching fresh meats and other foods, or by measuring pathogenic contamination; others can make packaging increasingly biodegradable.

SURFACE TO TOUCH SCREEN: BY THIN FILMS.

DISPLAX, a Portugal-based company, promises to turn any surface — flat or curved — into a touch-sensitive display. The company has created a thinner-than-paper polymer film that can be stuck on glass, plastic or wood to turn it into an interactive input device.

It is extremely powerful, precise and versatile and film can be used on top of anything including OLED and LCD displays.

Human-computer interaction that goes beyond keyboards and mouse has become a hot new area of emerging technology. Since Apple popularized the swipe and pinch gestures with the iPhone, touch has become a new frontier in the way we interact with our devices.

In the past, students have shown a touchscreen where pop-up buttons and keypads can dynamically appear and disappear. That facilitates the user to experience the physical feel of buttons on a touchscreen. In 2008, Microsoft offered Surface, a multitouch product that allows users to manipulate information using gesture recognition.

Displax’s films range from 3 inches to 120 inches diagonally.

Grids of nanowires are embedded in the thin polymer film that is just about 100 microns thick. A microcontroller processes the multiple input signals it receives from the grid. A finger or two placed on the screen causes an electrical disturbance. The microcontroller analyzes this to decode the location of each input on that grid. The film comes with its own firmware, driver — which connect via a USB connection — and a control panel for user calibration and settings.

Currently, it can detect up to 16 fingers on a 50-inch screen. And the projective capacitance technology that Displax uses is similar to that seen on the iPhone, so the responsiveness of the touch surface is great.

And if feeling around the screen isn’t enough, Displax allows users to interact with the screen by blowing on it. Displax says the technology can also be applied to standard LCD screens.

Displax’s versatility could make it valuable for a new generation of displays that are powering devices such as e-readers. For instance, at the Consumer Electronics Show last month, Pixel Qi showed low-power displays that can switch between an active color LCD mode and an e-reader-like, low-power black-and-white mode. Pixel Qi’s displays, along with other emerging display technologies from the likes of Qualcomm’s Mirasol and E Ink’s color screen are keenly awaited in new products because they promise to offer a good e-reader and a netbook in a single device.

But touch is a feature that is missing in these emerging displays. Displax could help solve that problem.

It is also more versatile than Microsoft Surface. The film is about 100 microns thick, while Surface is about 23 inches deep. Surface is not just another hardware solution, it includes integrated software applications and vision technology so it can respond to just the shape of the object.

Displax’s thin film offers a big breakthrough for display manufacturers because it they don’t have to make changes to their manufacturing process to use it. Displax says the first screens featuring its multitouch technology will start shipping in July.

NANOPARTICLE ORGANIC MEMORY FIELD-EFFECT TRANSISTOR

For the first time, CNRS (Centre National de la Recherche Scientifique; National Center for Scientific Research) and CEA researchers have developed a unique transistor that can simulate the main functionalities of a synapse.

This organic transistor, based on pentacene and gold nanoparticles and known as a NOMFET (Nanoparticle Organic Memory Field-Effect Transistor), has revolutionized modern computing world and inspired the researchers to create new generations of neuro-inspired computers, capable of responding in a manner similar to the nervous system.

In the development of new information processing strategies, one approach consists in mimicking the way biological systems such as neuron networks operate to produce electronic circuits with new features. In the nervous system, a synapse is the junction between two neurons, enabling the transmission of electric messages from one neuron to another and the adaptation of the message as a function of the nature of the incoming signal. For example, if the synapse receives very closely packed pulses of incoming signals, it will transmit a more intense action potential. Conversely, if the pulses are spaced farther apart, the action potential will be weaker. It is exactly the nature what researchers succeeded to have copied in the NOMFET.

A transistor, the basic building block of an electronic circuit, can be used as a simple switch - it can then transmit, or not, a signal - or instead offer numerous functionalities for example :amplification, modulation, encoding, etc.

The innovation of the NOMFET resides in the original combination of an organic transistor and gold nanoparticles. These encapsulated nanoparticles, fixed in the channel of the transistor and coated with pentacene, have a memory effect that allows them to transmit in a way a synapse does during the transmission of action potentials between two neurons. This property therefore makes the electronic component capable of evolving as a function of the system in which it is placed. Its performance is comparable to the seven CMOS transistors that have been needed until now to achieve this plasticity.

The devices produced have been optimized to nanometric sizes in order to be able to integrate them on a large scale. Neuro-inspired computers, produced using this technology, are capable of functions comparable to those of the human brain.

Unlike silicon computers, widely used in high performance computing, neuro-inspired computers can resolve much more complex problems, such as visual recognition.

NANOSCALE OPTICAL FIBERS FOR DETECTION OF BIOTERRORIST AGENTS

In an age when bacterial agents may be intentionally released as method of terrorist attack, there is an increased need for quick diagnostic methods that require limited resources and personnel. Thomas Inzana, the Tyler J. and Frances F. Young Chair of Bacteriology in the Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech, has been awarded a grant from the National Institutes of Health to develop such a diagnostic test.

He and his co-investigators, James “Randy” Heflin, a professor in the Department of Physics in the university’s College of Science, and Abey Bandera, a research assistant professor in the veterinary college, are working to develop nanoscale optical fiber biosensor tests, or assays, for detection of Francisella tularensis, Burkholderia mallei, and B. pseudomallei.

Currently, testing involves either the use of cultures in Biosecurity Level-3(BSL-3) laboratories, or since facilities do not have BSL-3 capabilities -- serology or antibody-based testing. Both require extensive materials and training, and the results can take days or weeks.

“This assay will be rugged, portable, inexpensive, and rapid,” said Inzana, who is also the associate vice president for research programs at the university. All of these are critical to minimizing the affect on an intentionally introduced biological weapon.

The increased speed of detection allowed by this new, optical fiber assay will also increase the speed of treatment for those affected, according to Inzana.

The optical fiber is coated with antibodies or DNA that will bind to antigens or DNA in the specimen. When this happens, the light that normally passes through the fiber will be decreased, indicating the presence of a biological agent.

According to Inzana, there are advantages and disadvantages to both. Antigens are more abundant and closer to the surface of the agent, but aren’t always very specific. DNA, however, is very specific, but is less plentiful and resides deep within the cell.

NEW METHOD PRESENTED FOR SYNTHESIS & GROWTH OF CARBON NANOTUBES

Researchers at the Plasma Physics Research Center of Iran's Islamic Azad University devised a new method to improve the synthesis and growth of carbon nanotubes. Carbon nanotubes synthesized in this new way can be used in manufacturing electron emitters and solid devices with high thermal conductivity.

Since 1991, along with the discovery of carbon nanotubes, researchers have always attempted to optimize their production and to utilize them in different industries. Majid Mojtahedzadeh Larijani, one of the researchers, undertook this study with the aim of synthesizing carbon nanotubes by a novel method, which is the growth on the beds with catalytic base by means of ionic bombardment.

The bed used in this study was steel. First in the process, sub-layer underwent surface was treated by argon ionic bombardment at different ion energies and doses. Then by Chemical Vapor Deposition method carbon nanotube growth on bombarded samples using hydrogen and steel gases was accomplished.

The results showed that ion energy and dose in which sub-layer surface turns into fine grains are very appropriate for the growth of dense and adhesive carbon nanotubes. These nanotubes could be applied for manufacturing electron emitters and solid devices with high thermal conductivity in electronics industry.