MONOLITHIC COMB DRIVE: A NANOSCALE MANIPULATOR

Jason Vaughn Clark, an assistant professor of electrical and computer engineering and mechanical engineering created a tiny motorized positioning device that has twice the dexterity of similar devices being developed for applications that include biological sensors and more compact, powerful computer hard drives. The device, called a monolithic comb drive, might be used as a "nanoscale manipulator" that precisely moves or senses movement and forces. The devices also can be used in watery environments for probing biological molecules.




The advantage of this device is that it can shrink the size of the overall sensor instrument. The sensors generally detect objects using two different componenets. A probe is moved while at the same time the platform holding the specimen is positioned. The new technology would replace both components with a single one - THE MONOLITHIC COMB DRIVE.



The researchers expected the sensors to work faster and at higher resolution. Also due to the single component they are small enough to fit on a microchip.The higher resolution might be used to design future computer hard drives capable of high-density data storage and retrieval. It could possibly be used to fabricate or assemble miniature micro and nanoscale machines.



Structure wise, the new monolithic device has a single structure with two perpendicular comb drives. It is so called because it contains comb drive components that are not mechanically and electrically separate. Conventional comb drives are structurally decoupled to keep opposite charges separated. Along with that there are certain advantages of comb drive overother technologies. In contrast to piezoelectric actuators that typically deflect, or move, a fraction of a micrometer, comb drives can deflect tens to hundreds of micrometers. And unlike conventional comb drives, which only move in one direction, new device can move in two directions - left to right, forward and backward - an advance that could reallyopen up the door for many applications.

DNA BASED SENSORS

Nano-sized carbon tubes coated with strands of DNA can create tiny sensors with abilities to detect odors and tastes, according to researchers at the University of Pennsylvania and Monell Chemical Sciences Center.According to the researchers, arrays of these nanosensors could detect molecules on the order of one part per million, akin to finding a one-second play amid 278 hours of baseball footage. Here the nanosensors are tested on five different chemical odorants including methanol and dinitrotoluene, or DNT, a common chemical that is also frequently a component of military-grade explosives. The nanosensors could sniff molecules out of the air or taste them in a liquid, suggesting applications ranging from domestic security to medical detectors. The nanaosensors could sniff molecules out of the air or taste them in the liquid.

Sensor is a hybrid of two molecules that are extremely sensitive to outside signals: single stranded DNA, which serves as the 'detector,' and a carbon nanotube, which functions as 'transmitter'. If they are put together they become an extremely versatile type of sensor, capable of finding tiny amounts of a specific molecule. Given the size of such sensors each carbon nanotube is about a billionth of a meter wide, these systems could be used as passive detection system in almost anylocation. The sensor surface is also self-regenerating, with each sensor lasting for more than 50 exposures to the targeted substances, which means they would not need to be replaced frequently.The specificity of single-stranded DNA is what makes these sensors so capable.

Likewise, the nanotubes are ideal for signalling when the DNA has captured a target molecule. Nanotubes are extremely sensitive to electrostatic variations in their environment, whether the nanotube is in a liquid or in air.When the DNA portion of the nanosensor binds to a target molecule, there will be a slight change in the electric charge near the nanotube. The nanotube will then pick up on that change, turning it into an electric signal that can then be reported. In this way an array of 100 sensors with different response characteristics and an appropriate pattern recognition program would be able to identify a weak known odor in the face of a strong and variable background.

ABOUT NANOMATERIALS

Over the past decade, nanomaterials have been the subject of enormous interest. These materials, notable for their extremely small feature size, have the potential for wide-ranging industrial, biomedical, and electronic applications. As a result of recent improvement in technologies to see and manipulate these materials, the nanomaterials field has seen a huge increase in funding from private enterprises and government, and academic researchers within the field have formed many partnerships.
Nanomaterials can be metals, ceramics, polymeric materials, or composite materials. Their defining characteristic is a very small feature size in the range of 1-100 nanometers (nm). The unit of nanometer derives its prefix nano from a Greek word meaning dwarf or extremely small. One nanometer spans 3-5 atoms lined up in a row. By comparison, the diameter of a human hair is about 5 orders of magnitude larger than a nanoscale particle. Nanomaterials are not simply another step in miniaturization, but a different arena entirely; the nanoworld lies midway between the scale of atomic and quantum phenomena, and the scale of bulk materials. At the nanomaterial level, some material properties are affected by the laws of atomic physics, rather than behaving as traditional bulk materials do.
Although widespread interest in nanomaterials is recent, the concept was raised over 40 years ago. Physicist Richard Feynman delivered a talk in 1959 entitled "There's Plenty of Room at the Bottom", in which he commented that there were no fundamental physical reasons that materials could not be fabricated by maneuvering individual atoms. Nanomaterials have actually been produced and used by humans for hundreds of years - the beautiful ruby red color of some glass is due to gold nanoparticles trapped in the glass matrix. The decorative glaze known as luster, found on some medieval pottery, contains metallic spherical nanoparticles dispersed in a complex way in the glaze, which give rise to its special optical properties. The techniques used to produce these materials were considered trade secrets at the time, and are not wholly understood even now.
Development of nanotechnology has been spurred by refinement of tools to see the nanoworld, such as more sophisticated electron microscopy and scanning tunneling microscopy. By 1990, scientists at IBM had managed to position individual xenon atoms on a nickel surface. In the mid-1980s a new class of material - hollow carbon spheres - was discovered. These spheres were called buckyballs or fullerenes, in honor of architect and futurist Buckminster Fuller, who designed a geodesic dome with geometry similar to that found on the molecular level in fullerenes. The C60 (60 carbon atoms chemically bonded together in a ball-shaped molecule) buckyballs inspired research that led to fabrication of carbon nanofibers, with diameters under 100 nm. In 1991 S. Iijima of NEC in Japan reported the first observation of carbon nanotubes1, which are now produced by a number of companies in commercial quantities. The world market for nanocomposites (one of many types of nanomaterials) grew to millions of pounds by 1999 and is still growing fast.
The variety of nanomaterials is great, and their range of properties and possible applications appear to be enormous, from extraordinarily tiny electronic devices, including miniature batteries, to biomedical uses, and as packaging films, super absorbants, components of armor, and parts of automobiles. General Motors claims to have the first vehicle to use the materials for exterior automotive applications, in running boards on its mid-size vans.
What makes these nanomaterials so different and so intriguing? Their extremely small feature size is of the same scale as the critical size for physical phenomena. Fundamental electronic, magnetic, optical, chemical, and biological processes are also different at this level. Where proteins are 10-1000 nm in size, and cell walls 1-100 nm thick, their behavior on encountering a nanomaterial may be quite different from that seen in relation to larger-scale materials. Nanocapsules and nanodevices may present new possibilities for drug delivery, gene therapy, and medical diagnostics.
Surfaces and interfaces are also important in explaining nanomaterial behavior. In bulk materials, only a relatively small percentage of atoms will be at or near a surface or interface (like a crystal grain boundary). In nanomaterials, the small feature size ensures that many atoms, perhaps half or more in some cases, will be near interfaces. Surface properties such as energy levels, electronic structure, and reactivity can be quite different from interior states, and give rise to quite different material properties.

SHATTERED BONES: ANSWER IS CARBON NANO TUBE

Human bones can be broken in accidents, or they can be disintegrated when ravaged by disease and time. But scientists at the University of California may have a new weapon in the battle against forces that damage the human skeleton. They have found a way to create a stronger and safer frame than the artificial bone scaffolds currently in use.

Carbon Nanotube, incredibly strong molecules just billionths of a meter wide, can function as scaffolds for bone regrowth, according to researchers led by Robert Haddon at the same University.

Human Bone is having two parts. One is organic and another one is inorganic. The organic part is made of collagen, which is the most abundant protein in mammals. The inorganic component is a type of calcium crystal named hydroxyapatite. The collagen forms a sort of natural scaffold over which the calcium crystals organize into bone. The idea in Haddon's research is to use the nanotubes as substitutes for the collagen to promote new bone growth when bones have been broken or worn down.

CNT: SUBSTITUTE FOR SILICON

The electrical properties of CNTs are extremely sensitive to defects which can be introduced during the growth, by mechanical strain, or by irradiation with energetic particles such as electrons, heavy ions, alpha-particles, and protons. When highly energetic particles collide, a latchup, electrical interference, charging, sputtering, erosion, and puncture of the target device can occur. Therefore the information on the effects of various types of high energetic irradiation on CNTs and other nanomaterials will be important in developing radiation-robust devices and circuits of nanomaterials under aerospace environment. As a result, degradation of the device performance and lifetime or even a system failure of the underlying electronics may happen. Researchers in South Korea conducted a systematic study of the effects of proton irradiation on the electrical properties of CNT network field effect transistor (FET) devices showing metallic or semiconducting behaviors. The most important outcome of this work is that no significant change in the electrical properties of CNT-based FET was observed, even after high-energy proton beam irradiated directly on the device. This result show that CNT-based devices can be a promising substitute for classical silicon-based devices, which are known to be very fragile against proton radiations.

It has been reported previously that electronic devices became more radiation tolerant when their dimensions are reduced.For example, multi-quantum well or quantum dot devices can be tens or hundreds times more radiation tolerant than conventional bulk devices. It even was shown that quantum dot/CNT-based photovoltaic devices were five orders of magnitude more resistant than conventional bulk solar cells.

NANO IN FUTURE SPACE MISSION

Nanotechnology will play an important role in future space missions. Nanosensors, dramatically improved high-performance materials, or highly efficient propulsion systems are but a few examples. Propulsion Technology, harden electronic components and radiation shielding are the areas where nanotechnology could make a major contribution to human space flight. According to NASA, the risks of exposure to space radiation are the most significant factor limiting humans’ ability to participate in long-duration space missions. Therefore a lot of research has been going on developing countermeasures to protect astronauts from those risks. To meet the needs for radiation protection as well as other requirements such as low weight and structural stability, spacecraft designers are looking for materials that help them develop multifunctional spacecraft hulls. Advanced nanomaterials such as the newly developed, isotopically enriched boron nanotubes could pave the path to future spacecraft with nanosensor-integrated hulls that provide effective radiation shielding as well as energy storage.

Actually space radiation is qualitatively different from the radiation human encounters on Earth. Once astronauts leave the Earth's protective magnetic field and atmosphere, they become exposed to ionizing radiation in the form of charged atomic particles traveling at close to the speed of light. Highly charged, high-energy particles pose the greatest risk to humans in space. A long-term exposure to this radiation can lead to DNA damage and cancer. One of the shielding materials under study is boron 10.

A stable isotope, 105B (Boron), having five protons and five neutrons, that makes up about 20% of natural boron is a good absorber of slow neutrons and is used as a radiation shield. It has also been used in numerous applications such as a dopant in the semiconductor industry. Boron compounds also play important roles as light structural materials, nontoxic insecticides and preservatives, and reagents for chemical synthesis.

Compared to Carbon Nanotubes, boron nanotubes have some better properties which make them more suitable for space industry. They are having high chemical stability, high resistance to oxidation at high temperatures and also they are stable wide band-gap semiconductors. Because of these properties, they can be used for applications at high temperatures or in corrosive environments such as batteries, fuel cells, super capacitors, high-speed machines as solid lubricant.

But the major problem is that large quantity production of pure boron nanotubes requires a large quantity of this material.

NANO HELPS TO REDUCE CORROSION

In a recent advancement by Air Office of Scientific Research, transparent coating have been developed that causes the water to roll off the surface which will in turn to protect Air Force system by preventing corrosion and reducing ice formation on optical systems and Aircraft.

NANO POWER: HOPE FOR THE RURAL HOMES

Now if you go to the country side and see the rooms enlightened, don't frown.Electrification of homes in rural areas would no more be a distant dream with the help of nanotechnology.

Jamshedpur-based Ekta Telecommunication and Systems is working on incorporating nanotechnology in the development of solar modules to provide electricity to all at an affordable rate. The advanced technology can be a boon for rural and urban homes. Increase in efficiency is another benefit of the technology.The technology, based on the use of a combination of solar cells to build a module and eventually a solar cell
would be developed with the use of thin polymer sheets. Electricity would be generated by placing the thin sheet on the rooftop and drawing solar the power for lighting up the entire house. “Solar electricity is the only answer to the power crisis in contemporary times.The adoption of nanotechnology would ensure that we can provide electricity to
people at prices lower than what the commercial power providers charge,” said Niraj Kumar Mishra, the chairman and managing director of Ekta Telecommunication and Systems. The company is also working on making the modules available at affordable prices. Ekta is also focussing on increasing the efficiency of the modules.The cost of the
modules would decrease to Rs 5 from the existing Rs 150 to Rs 250 per watt, said officials. The efficiency of the solar modules would go up to an average of 50 per cent from the present rate of 14 per cent.

BROKEN TEETH: DONT WORRY!

If you have a broken teeth, you may think that it is gone. But wait a minute! Nanotechnolgy helps you to recreate your teeth.

In a new development, scientists revealed recently that teeth broken could soon be regrown using an ultrasound machine half the size of a thumbnail. The process could take just 12 weeks. Ultrasound is already used to help heal broken bones, now the technology is being applied to teeth. Nanotechnology, which can reduce electronic circuitry to one thousandth of the size of a human hair, has enabled scientists to develop an ultrasound device small enough to fit inside the mouth. A wafer-thin ultrasound chip, which is preprogrammed so that it turns on automatically, can be clipped onto the teeth. When it is on, ultrasound waves massage the gums to stimulate and increase blood flow to produce new tooth tissue.

Exploring Nanotechnology: Infants get a new light

An Indian microbiologist is trying to use nanotechnology to help identify an opportunistic pathogen that colonises recto-vaginal areas in up to 50 per cent of women worldwide and causes several life-threatening diseases in infants. Atul Kumar Johri, Associate Professor at JNU's School of Life Sciences in New Delhi, is keen to develop a mechanism to identify Group B Streptococcus (GBS) bacteria that cause pneumonia, sepsis and meningitis in newborns and is responsible for significant morbidity in pregnant women and the elderly.

Dr. Johri along with scientists from the Queensland Institute of Medical Research in Australia is working on a project to make use of nanotechnology for rapid, more sensitive as well as efficient detection of the GBS bacteria in pregnant women.

In the U.S., the UK and France, there is a mandatory test for detection of GBS in pregnant women between 35-37 weeks of their pregnancy. If the bacteria are detected in their samples, four hours before the birth of the child penicillin shots are given to the women through intravenous injections so that they can prevent the bacteria from infecting the baby and causing pneumonia and meningitis.

In India, there is no such test or even much knowledge about the existence and prevention of GBS. The fact that a large number of childbirths in the country happen outside the health centres is another cause for worry.
“Timely detection of GBS can save a lot of babies in India. The problem is that in India, common people are not even aware of such a micro-organism, diseases that it causes, and that it is so easily preventable. GBS has nine serotypes. In India, Type I-A and Type III are predominant. After they made the test mandatory, the number of children getting infected with such diseases in the Western countries has come down significantly,” informs Dr. Johri. He is also working with the Australian researchers to develop one universal vaccine for the GBS.

SUPERSONIC ELECTRIC AIRCRAFT

Commercial aviation is an essential component of the global economy. The cost of aviation fuel is directly determined by the prevailing world price of oil. It accounts for a major proportion of airplane operating costs. Several airline companies now add a fuel surcharge to the ticket cost of a commercial flight to compensate for the recent rapid rise in fuel costs. World oil prices are expected to remain high for several years. The prospect of sustained high aviation fuel prices could propel airline companies to seek alternative aviation fuels. Seeking alternative fuel could become become paramount for the airline industry should the peak-oil phenomena actually occur. The commercial aviation industry would likely compete for fuel and energy in a market of scarcity and escalating fuel prices.

Breakthroughs and Research

It may become possible for supercooled liquid hydrogen to eventually be used as an alternative fuel for some types of commercial airline service. Extensive research will be needed to resolve the numerous logistical problems that are related to its use as an alternative aviation fuel in supersonic and hypersonic aircraft. Other alternative fuels may include high-density energy-storage technologies that result from breakthroughs in research in the areas of nanotechnology and in high-temperature superconductivity.

Sporadic and significant breakthroughs periodically occur in both fields. High-temperature superconductivity holds great promise for use in high-density energy-storage technology. A coil formed into a torus and made from "high-temperature" superconductive material could theoretically store enough energy to enable a full-sized commercial airliner to undertake an extended trans-oceanic or trans-continental flight. Advances in nanotechnology could enable superconductive materials to eventually be manufactured at a cost that could justify their application in airliner propulsion.

Electrical Storage and Propulsion

Energy stored in a superconductive storage technology could power electric motors that drive the identical propulsion fans that are found at the front-end of modern, "high-bypass" turbo-fan aircraft engines. Such fans provide up to 90% of the propulsive thrust of the turbo-fan engine. Each electrically powered propulsion fan may be driven by multiple (induction) lightweight electric motors during take-off. Some electric motors would "cut-out" under reduced power demand at cruising altitude so that the remaining motors will operate at higher efficiency (electric motors have poor part-load effciency).

Coanda fans may propel subsonic commercial aircraft that use high-density electrical storage technology. Such units were originally developed by physicist Henri Coanda and can operate at comparable efficiency and at comparable flight speeds as turbine-driven propulsion fans. Electrically powered aircraft that use either turbine propulsion fans or Coanda fans could be flown in thinner air at higher altitude (up to 65,000-feet) to reduce energy consumption (less drag on aircraft) on extended flights. The cooler air found at such altitudes could assist in keeping the superconductive energy storage systems functioning properly.

Superconductive energy storage systems used in future commercial aircraft would likely be cooled by liquid nitrogen. Both systems would need to be frequently recharged. Commercial aircraft that operate long-haul service usually undergo cleaning and servicing in hangars after long flights. It is during such service periods when the energy storage and cooling systems could be recharged, a process that would likely be both energy-intensive as well as time consuming.

It may be possible to design the energy storage systems along with their cooling systems to be removed and replaceable during shorts layovers. Such technology may be possible and could help reduce the turn-around time of the aircraft. The introduction of superconductive energy storage systems in commercial aircraft in the long-term future would require that future airport terminals be equipt with power generation technology at or near the premises.

Short-haul/Commuter Aircraft

Aircraft turbine engines are very flexible in the kind of fuel that they can burn. Short-haul and commuter airline companies that operate routes of under 500-miles would be the most likely candidates to use alternative aviation fuel. Their fleets are mainly powered by turbo-prop or by turbofan engines and may likely have sufficient capacity in the fuel tanks to carry a cheaper fuel with a lower energy content. They may use such fuel if its cost per BTU undersells fossil aviation fuel. Breakthroughs in electrical storage technology could see a future generation of short-haul and commuter aircraft being propelled by electric motors driving propellers or propulsion fans.

Low-Altitude Flight

Ground-effect aircraft use a specialized wing design that generated a cushion of air between the wing and the surface over which it flies. Large and heavy versions of such aircraft could be flown at moderate speed over water and carry passengers and freight between coastal centres of up to 500-miles apart. Eliminating the need for take-off to at least 10,000-feet would cut fuel costs. The performance of such craft can be enhanced by a recent development from Britain that has been successfully tested in a scale model aircraft.

Aeronautical "paddle wheels" are mounted transversely on the topside of aircraft wings to provide propulsion and increase lift at very low flight speeds. Such craft may to be propelled by electrically driven propellers that are the size of helicopter rotors. Such units can move a large mass of air at lower velocity to deliver high thrust (200,000-lbf per propeller) at higher propulsive efficiency. An alternative system could see heated air being ducted through the thick rotor blades to adjustable jets that are built into the tips of the rotors.

Low Speed (Electrically-powered) Supersonic Flight

An American company called Supersonic Aerospace International (SAI) recently undertook research into reducing the sonic boom of supersonic commercial flight. The result was a unique configuration of supersonic aircraft capable of flying quietly at Mach 1.5. It is theoretically possible to develope an electrically powered engine capable of propelling a commercial aircraft to such a flight speed.

A high-temperature superconductive energy storage system would supply power to 2-sets of electric motors that drive different propulsion systems. A subsonic propulsion system of electrically driven propellers would accelerate the aircraft up to a flight speed of Mach 0.5 when the supersonic engines would engage. These engine would have a cross sectional profile similiar to that of a ramjet.

The electric motor and compressor would be housed in a straight tube intake pipe that would be flowed by a section of gently increasing diameter. A shock wave at the entrance of the pipe would see air speed drop from Mach 1.5 to Mach 0.7. The air temperature would rise from minus 40-degrees F to 95-degrees F. An electrically driven axial flow (single spool) compressor operating at 93% isentropic efficiency and having a pressure ratio of 8 to 1 would further increase air temperature to 580-degrees F.

The heated air would flow into the diffuser (where area quadruples) where air pressure would increase by up to 25% and air temperature would rise to 648-degrees F at the maximum cross section. Air would then flow into a nozzle (smaller cross section) at sonic speed and accelerate into a diverging exhaust section where air would leave at over 2534-feet per second (Mach 1.5 at -40-degrees F is 1507-feet per second). The engine would move a very large volume of air to provide sufficient thrust to maintain flight speed. A pressure ratio of 10:1 on the compressor could raise the exit velocity of the air to 2704-feet per second.

Faster Supersonic Flight

The electrically powered engine that could theoretically propel an aircraft to a flight speed of Mach 1.5 could be modified to operate at higher speed. The engine intake would be modified to an "Oswatitsch" design with variable geometry. That design would generate (weaker) oblique shock waves at the entrance to the engine as well as be able to "dump" excess air or duct in extra air depending on flight conditions.

The faster engine may use a single-spool axial flow compressor that has more pressure ratio (up to 15 to 1 with variable stator blades) to raise air temperature. The aircraft may carry water in special tanks and electrolysis gear to generate hydrogen that may be injected ahead of the nozzle of the engine. The combustion of the hydrogen would increase the air temperature and raise the exit velocity of the gas that leaves the engine. Flight speeds of Mach 2 to Mach 2.4 may be possible.

Power Generation

The number of electrically powered and hydrogen powered road and railway vehicles would likely increase during a post peak-oil period. Commuter aircraft that operate short-haul service could be powered by ethanol or by hydrogen while future supersonic aircraft could use liquid hydrogen as fuel. The commercial aviation industry of the future (post peak oil) could likely require vast amounts of electric power to recharge superconductive energy storage systems, recharge liquid nitrogen cooling systems as well as to generate, compress and supercool large amounts of hydrogen.

Modern commercial aircraft are energy intensive during take-off. Airports that serve metropolitan areas presently process continual processions of large long-distance aircraft during peak periods. Such aircraft could require between 300-Mw-hr and 1000-Mw-hr of power to undertake trans-oceanic flights at subsonic speed. The power requirements of a future electrically based commercial aviation industry could likely overwhelm the power generation industry of most developed nations.

Major international airports may eventually need to generate electric power on-site to meet the energy needs of future fleets of electrically powered and hydrogen-fueled commercial aircraft. Airport power stations may be nuclear; use hydrogen fusion or be based some other unconventional power generation technology that is still subject to research. The heat that will be rejected by these thermal power stations could be reclaimed and put to productive use that would would include:

* Heating buildings (district heating) during winter.

* Putting heat into geothermal storage during summer for use during.

* Powering absorption air-conditioning systems during summer.

* Energising low-grade heat engines to generate electricity during winter.

Energy Storage

The ability to store large amounts of energy at or near major airports could gain importance during a post peak-oil period. Electric power could be purchased from the grid during their off-peak periods and put into short-term storage. Airport power stations that encounter off-peak periods could replenish airport energy storage systems that may include superconductive storage, flow batteries, hydraulic storage in hydroelectric dams in nearby mountains (coastal airports) or off-site pneumatic storage (subterranean salt domes that were emptied). Air that is exhausted from pneumatic storage systems may be sufficiently cold to assist in "replenishing" liquid nitrogen supercooling systems.

Power Regulation (Airports)

Power stations that provide energy for air transportation use may have to be excluded from the regulatory framework. Most of the electrically powered airliners that will be recharged would be "foreign" owned, that is, the owners would be domiciled in a different jurisdiction to where the aircraft would be recharged. The idea of regulators in one jurisdiction looking after the interests of parties who live, do business and pay taxes in another jurisdiction is quite ludicrous. Power stations that supply a future airline industry with electric power would need to be regulatory-free despite the "foreign" airline owners being "captive" customers. It would be possible for power to be supplied to a single airport by several small providers who compete against each other. Power providers and airline companies could negotiate deals including on a daily basis.

Conclusions

Future scientific breakthroughs are likely to occur in both nanotechnology and in superconductivity. High-density energy storage technologies could be the likely result and appear in the distant future. Electrically powered commercial aircraft that fly at subsonic speeds could appear in the future irrespective of whether or not peak-oil actually occurs. Alternative liquid fuels that are cost-competitive to fossil oil are also likely to appear and find application in aviation. Large ground-effect aircraft that fly above water and that carry either passengers or freight between coastal cities are also likely appear in the future.

VIRUS: Nano particle Memory Booster

A new type of digital memory device has been created by incorporating inorganic platinum nanoparticles into the tobacco mosaic virus (TMV).

The work was done by researchers at the University of California, Los Angeles (UCLA), who claim that the result could find application in the development of bio-compatible electronics.

In recent years researchers have exploited the unique selectivity of biomaterials by nanostructuring biological molecules with inorganic materials for applications such as biosensing. The UCLA researchers have taken this idea one-step further with a hybrid biological system that can store digital information.

“We have developed an electronic device, fabricated from the tobacco mosaic virus conjugated with nanoparticles, which exhibits a unique memory effect,” Yang Yang, the group’s lead researcher at the University of California, told physicsweb.org. “This device can be operated as an electrically bistable memory device whose conductance states can be controlled by a bias voltage. The states are non-volatile and can be digitally recognized.”

The TMV is a 300 nm tube consisting of a protein capsid (outer shell) and RNA core. According to the researchers, the TMV’s thin, wire-like structure makes it suitable for attaching nanoparticles. In this case, it allowed them to add an average of sixteen positive platinum ions per virion. The device works by transferring charge, under a high electric field, from the RNA to the Platinum nanoparticles with the TMV’s surface proteins acting as an energy barrier, stabilising the trapped charges.

“The TMV’s surface makes it an ideal template for organizing the nanoparticles, which can bind to the specific carboxyl or hydroxyl sites on the surface,” said Yang. “The RNA core in TMV is likely to serve as the charge donor to the nanoparticles with the coat proteins acting as the barrier to the charge transferring process.”

The TMV hybrid, says the team, has an access time ( the delay between a call for storing data and for data storing to begin) in the microsecond regime. This is comparable to today’s flash memory. In addition, the device is non-volatile, which means that data is retained once the computer’s power is turned off.

The researchers say the device still needs to be scaled-down to a smaller size to increase storage density and to include more circuitry. “There will be issues involving retention time, power consumption, and integration of drivers required to write and read each bit, which we need to consider in order to optimize the system,” said Yang.

In the long term, these devices could one day be integrated in biological tissues for applications in therapeutics or biocompatible electronics.

SILICON QUANTUM COMPUTER

Keio university researchers are working on a project to produce a revolutionary quantum computer using 'silicon', the same material as present classical computers, which can work as a bridge between classical and quantum mechanics. The quantum computer based on silicon is designed and developed. Present computers work on the basis of the law of the classical mechanics that Newton and Maxwell established. On the other hand, a computer operating with the absolutely new concept based on the law of the quantum mechanics that Einstein et al. found in the 20th century is a quantum computer. Its implementation requires not just understanding of the quantum mechanics from its basics but also knowledge and technology to integrate creatively mathematical computer science and nanotechnology at an atomic level.