NANOTECH INNOVATIONS

Carbon nanotubes (CNTs) are among the most promising novel nanomaterials and their unique chemical and physical properties suggest an enormous potential for many areas of research and applications. As a consequence, the production of CNT-based material and thus the occupational and public exposure to CNTs will increase steadily. Although there is evidence that nanoparticles (NPs) can enter the nervous system via the blood stream, olfactory nerves or sensory nerves in the skin, there is still only little knowledge about possible toxic effects of CNTs on cells of the nervous system.

The goal of the present study was to analyse the influences of single-walled CNTs (SWCNTs) with different degrees of agglomeration on primary cultures derived from chicken embryonic spinal cord (SPC) or dorsal root ganglia (DRG). As measured by the Hoechst assay treatment of mixed neuro-glial cultures with up to 30 μg/mL SWCNTs significantly decreased the overall DNA content. This effect was more pronounced if cells were exposed to highly agglomerated SWCNTs as compared to better dispersed SWCNT-bundles. Using a cell-based ELISA we found that SWCNTs reduce the amount of glial cells in both peripheral nervous system (PNS) and central nervous system (CNS) derived cultures. Neurons were only affected in DRG derived cultures, where SWCNT treatment resulted in a decreased number of sensory neurons, as measured by ELISA. Additionally, whole-cell patch recordings revealed a diminished inward conductivity and a more positive resting membrane potential of SWCNT treated DRG derived neurons compared to control samples.

The SWCNT suspensions used in this study induced acute toxic effects in primary cultures from both, the central and peripheral nervous system of chicken embryos. The level of toxicity is at least partially dependent on the agglomeration state of the tubes. Thus if SWCNTs can enter the nervous system at sufficiently high concentrations, it is likely that adverse effects on glial cells and neurons might occur.

Columns, pipes, bearings and springs are a few common ways that engineers have made use of the geometric shape known as a 'cylinder.' The utility of this shape is apparent in architecture, plumbing and mechanical devices. Carbon nanotubes are molecular cylinders that are rapidly extending our ability to fabricate nanoscale devices by providing molecular probes, pipes, wires, bearings and springs.Their strength as structural supports comes from their sturdy molecular structure, which looks like what one would get if one could roll a two dimensional sheet of graphite into a three dimensional cylinder.

The limit to how long they can be is unknown, thus aerospace scientists are seriously considering using them as cables extending into space, an idea that is not possible with traditional ropes since they would break under their own weight. Furthermore, carbon nanotubes can easily be cut into sections as small as a few nanometers . One of the first important applications of carbon nanotubes has been in the fabrication of sharp, strong and functionalized AFM probe tips.

The hollow nature of nanotubes allow them to function as pipes for transporting and molding atoms and molecules. Furthermore, the tubes come in insulating, semiconducting and conducting form, meaning that they can also be used as molecular wires and circuits . Whats more, capillary induced filling of the nanotubes with other materials further extends the diversity of nanowires that can be fabricated.

The electronic properties of carbon nanotubes are directly related to their shape, making them an important Nano-Electromechanical System (NEMS). For example, the feasibility of a nanotube-based random access memory device with a memory density around 100 gigabytes/cm2 and an operation frequency around 100 gigahertz has recently been developed at Harvard University.In addition to their high aspect ratio (meaning long and thin) and particle transport capabilities, carbon nanotubes can also function as durable bearings and springs. Nanotubes can be fabricated in two forms: single-wall nanotubes (SWNT) or multi-wall nanotubes (MWNT). While a SWNT consists of only a single cylinder, a MWNT consists of several (between 2 and 30) concentric tubes, each with a specific diameter. Physicists at the University of California, Berkeley have recently demonstrated that a MWNT can act as a molecular bearing when one of the inner tubes rotates, or as a molecular spring when an inner tube is pulled out, causing the MWNT to stretch in a way similar to a telescope .

The consumer world is exploding with “nanotechnology enhanced” products. Consumer products is an area where the experts are saying the most immediate nanotechnology impacts will be made and recognized by the majority of people in the world. Currently there are numerous products on the market that are the result of nanotechnology.For the sporting enthusiast, we have tennis balls that last longer, tennis rackets that are stronger, golf balls that fly straighter, nano ski wax that is easier to apply and more effective than standard wax, and bowling balls that are harder; and these products are just scratching the surface.

These products all use nanostructured materials to give them enhanced performance. Speaking of scratching the surface, we also have nano car wax that fills in those tiny cracks more effectively and gives you a shinier vehicle. There are also nano products available to keep your eyewear and other optical devices cleaner, dryer, and more durable. In the clothing world, we have pants that repel water and won’t stain shirts and shoe inserts that keep you cool in the summer and warm in the winter, and nano socks that don’t “stink” due to the inclusion of nanotech materials (nanosized sliver particles).

Nano-ceramic coatings are being utilized on photo quality picture paper to deliver sharper, higher quality “homemade” digital photo reproductions on your ink jet printer. How about that DVD you watched last night? Any idea how big the features on that now ubiquitous product are? DVD “bumps” to store information at 320 nanometers wide/The world of electronics has been using many of the key methods shared by other nanotechnology disciplines for many years. As an example, think of the evolution of the video game.

Nanotechnology has enabled arcade size video games of yesteryear like Pong, Frogger, and PacMan to be replaced with very sophisticated home Playstations, X-Boxes, and Game Cubes that play “life like” Madden 2005, Grand Theft Auto, and Halo 2 video games. There are also a tremendous amount of other electronic applications out there that are effecting our every day lives. Just take a trip to your local electronics mega-store and you will see a multitude of these including: faster and more powerful computers, palm pilots (blackberries), flash drives, digital cameras and displays, cell phones, LCDs, LEDs, MP3’s, electronic ink displays, thin film batteries, and flexible electronics to name a few. All of these applications are possible and affordable due to the ability to work effectively and efficiently at the nano-scale.

The biotech world also has many real world applications currently in use or under development that are, or will be, affecting our quality of life. Bandages embedded with silver nanoparticles are coming of age in the wound healing arena. And We now have drug delivery via a patch. A variety of time release thin films are now utilized on implantations into the human body (for example screws, joints, and stents) and these films are affecting the long term effectiveness of these devices,. Respiration monitors utilizing nano-materials have been developed that are many times more sensitive than previous state of the art technology.

Man-made skin is a nanofabricated network and is presently in use for skin graft applications. Some other nanotechnology applications which are currently under development in the biotech world are diabetic insulin biocapsules, pharmaceuticals utilizing “bucky ball” technology to selectively deliver drugs, and cancer therapies using targeted radioactive biocapsules.The world around us is filled with applications that nanotechnology makes possible. Don’t believe it? Look around! You won’t have to look far before these applications become evident to you. Nanotechnology is influencing the development of a wide variety of very diverse fields; among these are electronics, biotechnology, and consumer applications. From tennis balls to bandages to palm pilots, nanotechnology is making a significant impact on the jobs we work at and the products that we enjoy.

As devices become smaller the principles of quantum mechanics become more and more imperative. Many new theoretical ideas have come into view and fundamental quantum physics researches have progressed in leaps and bounds over the last few years.

Consequently, features of genuine Quantum Information Processing could soon begin to be feasible commercially. Quantum Information Processing (QIP) is a major area for research materials such as Gallium Nitride (GaN) or diamond-like-Carbon which can be potentially renovated into efficient devices.

Quantum computing which was suggested in 1970s completely relies on quantum physics, which permits the atoms and nuclei to work together as quantum bits or qubits and to be the computers processor and memory. Qubits can execute calculations exponentially faster than conventional computers. One important aspect of the communication sector is the security of information exchange. As the life is going to be networked in all sectors it is crucial to give more emphasis on the confidentiality of the official as well as personal mails. Quantum computing provides us unlimited processing power and secure communications. Those days have come to reality, when we can decode the encrypted conversations by terrorists or others. The compactness and the rapidness were the main achievements that the new developments in this era have brought out. The miniaturization as well as fast and rapid satellite communications, wireless LAN systems, cellular phones etc. are possible only because of the smart nano materials.

Now the science and technology has developed to such an extent that a group of scientists were able to flip the electron and they noticed a current change associated with it. They have tried to flip a single electron upside down in an ordinary commercial transistor chip. That was the beginning of the quantum computers where a single electron spin represents a quantum bit, the fundamental building block of a quantum computer. It was amazing that the conventional silicon technology was sufficient and powerful enough to accommodate the future electronic requirements like quantum computing, which will depend on spin. Another recent approach of Jiang and Xiao was that to shine microwave radio frequency to flip the spin of electron. The experiments last but a fraction of second, but required years of work to reach this point.

With 100 transistors, each containing one of these electrons, we could have the implicit information storage that corresponds to all of the hard disks made in the world this year, multiplied by the number of years the universe has been around. As we have discussed quantum computation makes use of atoms as a basis for computation. Unlike classical logical devices, which only exist in two states (0 or 1), atoms can have three states (0 or 1 or 01 where the latter is a superposition of the first two states). Recently developed DNA computing provides an example of long term information storage. It is very compact and replicable; however it is not very fast. So its use as a model for information processing seems to be limited. Even in biological systems short term information storage is an energy consuming process. One example is the brain activity. This information storage timescales are very low when compared with microelectronics. Quantum structure electronic devices (QSDs) can confine electrons into regions of less than 20 nm, enhancing their performance.

A principal aim of nanotechnology is to produce threedimensionally confined quantum structure electronic devices such as quantum wire and quantum dot devices. Some successful devices in this direction are quantum well lasers for telecommunications; High Electron Mobility Transistors (HEMTs) for low noise, high gain microwave applications; and Vertical Cavity Surface Emitting Lasers (VCSELs), for data communications, sensors, encoding and so on. Other application gadgets based on quantum dots, are on the verge of commercialisation.

Introduction

Ever since the origin of life, communication in one form or the other was there in the history. Even the minute form of life such as bacterium and fungi are communicating, though the mechanism is different. There was an earlier saying that history cannot be changed. But the technology especially nanotechnology makes the revolutions in the history. There is no present and future, the development was such like a dream come true when one gets up from the sleep. In communication sector always the major factor was the medium.

The change was so rapid that no one realized when the pigeon has become electrons. It is really thought provoking that how nanotechnology brings out revolutions in telecommunication as well as computing and networking industries.Forthcoming developments in nanotechnology through which the impossible can be made possible are nanomaterials with novel optical, electrical, and magnetic properties, compact as well as fast non-silicon based chipsets for processors, quantum computing and DNA computing, development of telecom switches which are fast and reliable, micro-electro-mechanical systems and above all the development of imaging and microscopic systems with high resolution. So for these reasons it is not futile to examine the broad range of nanotechnology and the revolutions made by it in the field of telecommunications. Hence a detailed account of the types of communications and the recent development in this field is essential.Electronic communication and informaticsElectronic communication can be defined as a communication by means of guided or unguided electromagnetic energy or both. Or it is a general term describing all forms of communication via electronic means such as internet, facsimile, satellite, cable, television, computers, networks, etc.

A coherent technology will be required to continue the performance improvements in communication and informatics. Nanotechnology interphased with biological, physical and chemical sciences can bring much faster and powerful information handling equipments. The sudden leap to the nano regime will result in single-molecule and single-electron based transistors. And special devices can be made out of these kinds of transistors. Informatics is primarily concerned with the structure, creation, management, storage, retrieval, dissemination and the transfer of information. Informatics mainly has a processor which translates one programme to another which can be accessed and used. Hence it is the backbone of the communication sector. Each processor will contain definite number of transistors with specific functions associated with it.

The first micro processor only had 22 hundred transistors.Now we are looking for the processors with a billion transistors so that the flexibility of designingdevices will be enormous. The present communication systems are based fully on the silicon technology. In 1965, Intel co-founder Gordon Moore saw the future and he predicted that the number of transistors on a chip doubles about every two years. His prediction is popularly known as Moore’s law. Moore’s Law is coming to an end now, since microelectronics has so far not only sustained this pace but it has crossed the limit of the prediction.

Recently Intel has introduced 65 nm generation logic technology which helps in improving performance and reducing power. They introduced sleep transistors which conserve power by allowing transistors to sleep when not in use, similar to the human brain. Intel strained silicon enables faster transistors by physically stretching the lattice structure of silicon atoms, allowing electrons to flow faster with less resistance. As can be seen, the silicon technology is entering into a near molecular regime as the current size has gone down to 25 nm.

This scenario can even slowdown or even curtail the progress of silicon microelectronics where not only the manufacturing technology but also the fundamental science changes. Intel developed a new, ultra-fast, yet very low power 85 nm prototype transistor using indium antimonide (InSb) that could form the basis of microprocessors and other logic products beginning in the second half of the next decade. The prototype transistor is much faster and consumes less power than previously announced transistors. If it is possible to manipulate light at small scales, photonic technologies will takeover silicon technology. Smart molecules can be integrated into devices for specific applications such as protein based transistors. Novel nano electronic properties of carbon nano tubes are also found suitable for developing an alternate technology.

Introduction
Metal nanomaterials have received considerable attention in the last decade in science and technology. The nature and behavior of the metal nanomaterials are different from that of the bulk material. Metal nano particles find wide application in various fields. Metals are unique in their physical and chemical properties as compared to other compound materials such as metal oxides, sulphides and nitrides. Metals have ductility, malleability, luster, high density, fewer defects and are generally crystalline in nature. Though the metal nanoparticles were synthesized and used from the ancient days even in the era of the Alchemists, lack of enough characterization techniques such as electron microscopes has left the nanoscience unexplored till recently.

In ancient days, the only characterization of metal nanoparticles is naked eye. The colouring nature of Au and Ag nanoparticles was fundamental identification for their nanoparticle colloid formation. Making use of this, they have been used as coloring agents in decorative glasses and clothing. This is due to light-absorbing nature of the surface of Au and Ag nanoparticles because of the surface plasmon resonance. Pt nanoparticles are catalytically active for oxidation and reduction reactions. As a result, these nanomaterials find applications for catalytic use. Since Au, Ag and Pt nano particles have considerable stability as compared to other metals, they have gained importance.

However, in the near future, all metals will be possibly shaped in nanosize by using suitable stabilizing agents and medium. In this chapter nature and applications of the nanomaterial of chosen metals are described. However, closer to each other in the periodic table, the physical properties of the nanosize materials of these metals vary drastically. To begin with, it is essential to comprehend fundamental properties of these (Ag, Au and Pt) metals.

The impact of scanning probe microscopy (SPM) over the past 20 years has been dramatic: its invention was, for example recently rated the second most important advance in materials science of the past 50 years.

The impact of scanning probe microscopy (SPM) over the past 20 years has been dramatic: its invention was, for example recently rated the second most important advance in materials science of the past 50 years. SPM techniques share a common feature, the use of a probe to detect a spatially localized signal. In most cases it is the probe that limits the spatial resolution of the technique.

The most common form of SPM is atomic force microscopy (AFM), where the probe is a sharp tip, usually mounted on a microscale cantilever that acts to transduce the tip–sample force (the localized signal). A map of surface topography is constructed by scanning the tip across the substrate. The resultant image is a convolution of the tip geometry with the surface topography. Commercial AFMs can have sub-Ångström noise levels, but the realizable lateral spatial resolution is limited by the tip geometry and is typically around two orders of magnitude larger.

For an ideal AFM tip, the exact tip geometry and chemistry should be known, the tip dimensions should be as small as possible without sacrificing rigidity, and the probe should be capable of imaging over a long lifetime, while aintaining a constant geometry.Attempts have been made to create ‘ideal’ tips using methodologies such as focused ion-beam structuring of the tip apex. However, the above requirements are perhaps best met by carbon nanotubes: cylindrical shells of graphene with diameters as small as 1 nm. Indeed, carbon nanotubes show great promise as AFM tips despite the substantial challenges involved in their fabrication. [Wilson and Macpherson doi: 10.1038/nnano.2009.154 ]present a review article that looks at the progress in the production and application of carbon nanotube AFM tips since their arrival onthe SPM scene in 1996.A readily available source of nanotube tips would further open up the AFM imaging world, increasing tip longevity, reducing tip imaging artefacts, increasing resolution and decreasing tip–surface forces.

It would also have a significant impact in key research areas such as structural biology, biotechnology, metrology and nanoelectronics.The question then remains, why are nanotube tips not being used routinely for AFM imaging and characterization? The answer lies in the fabrication. Progress in this area is being made, but obstacles still remain. However, the significant rewards waiting will ensure that this remains an active area for the foreseeable future.