Your SlideShare is downloading. ×
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Nanotech
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Nanotech

6,835

Published on

Published in: Education
2 Comments
8 Likes
Statistics
Notes
No Downloads
Views
Total Views
6,835
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
447
Comments
2
Likes
8
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Table of ContentsNanotechnologyINTRODUCTION .............................................................................................................1History of Nanotechnology.................................................................................................2Fundamental concept of Nanotechnology...........................................................................4Molecular Nanotechnology................................................................................................. 5Potential Benefits of Nanotechnology.................................................................................6Two main approaches for producing Nanomaterials............................................................7Tools and techniques used in Nanotech...............................................................................9Applications of Nanotechnology.........................................................................................11Nanotechnology used in various fields................................................................................12Implications and Regulations of Nanotech..........................................................................23Conclusion and References..................................................................................................24
  • 2. NanotechnologyINTRODUCTIONA lot of universities and centers, governments research centers and many other institutesdealing with nano-tachnology offer different definition for the nanotechnology. As thedefinition we can say that:“Nanotechnology is basically the control and understanding of the meter at the smallestlevel of about 1 to 100 nanometers, where, where this unique technology enhances novelapplications.”The technology of nano is that which is differentiated first and foremost on the basis of thescale on which it acts; the nanotechnology can be up to one billionth of a meter or the one-tenthousandth of the thickness of a human hair. Individual atoms or molecules are fundamentalactivities that are engaged in nano scale. Consequently, nanotechnology is said to besimulated exploitation of atomic or molecular matter or processes. Simply, now a day’snanotechnology is being manufactured at a very small scale like we can say that at the levelof atomic or molecular scale.Nanotechnology (sometimes shortened to "nanotech") is the manipulation of matter on anatomic and molecular scale. Generally, nanotechnology works with materials, devices, andother structures with at least one dimension sized from 1 to 100 nanometres. Quantummechanical effects are important at this quantum-realm scale. With a variety of potentialapplications, nanotechnology is a key technology for the future and governments haveinvested billions of dollars in its research. Through its National Nanotechnology Initiative,the USA has invested 3.7 billion dollars. The European Union has invested 1.2 billion andJapan 750 million dollars.Nanotechnology is very diverse, ranging from extensions of conventional device physics tocompletely new approaches based upon molecular self-assembly, from developing newmaterials with dimensions on the nanoscale to direct control of matter on the atomic scale.Nanotechnology entails the application of fields of science as diverse as surface science,organic chemistry, molecular biology, semiconductor physics, microfabrication, etc.Nanotechnology is also regarded as a feature of all methodical disciplines such as physics,chemistry, environmental science, material science, manufacturing-moderately than anotherfield of science. Nanotechnology has developed such an importance that is providesassistance to all industries except being an industry itself.Scientists debate the future implications of nanotechnology. Nanotechnology may be able tocreate many new materials and devices with a vast range of applications, such as in medicine,electronics, biomaterials and energy production. On the other hand, nanotechnology raisesmany of the same issues as any new technology, including concerns about the toxicity andenvironmental impact of nanomaterials, and their potential effects on global economics, aswell as speculation about various doomsday scenarios. These concerns have led to a debateamong advocacy groups and governments on whether special regulation of nanotechnology iswarranted.
  • 3. HISTORY OF NANOTECHNOLOGYThe background of nanotechnology is full of mysteries & cynicism. Some people weredetermined on this statement that this is fresh form of scientific development & it would notflourish until the arrival of 1990s.Some other verified that the history of nanotechnology can be map out back in early 1959.Moreover, as scientific expansion goes wider, nanotechnology is still spanking new arena ofscientific research.Still other developers believe that human has engaged realistic nanotechnological methodsfor thousands of years, possibly even longer.Nanotechnology is the maturity of evolution, as most of people situate it, and growth hasincluded the vulcanization of rubber. These progresses count in the record of nanotechnologyaccording to many recognized scientific experts.Possibly it might be more secure to admit that the fundamentals of history of nanotechnologyhave been applied for thousands of years or longer but we as a scientific society did not placea name to it until somewhere in 1960s.The mid nineteen’s generate the talent to identify the particles via the use of an ultramicroscope that could notice particles as small as 1/1 millionth of a millimetre. This is aparticle smaller than most general public cannot visualize perfectly. So, there are up till noweven more detractor that describes the history of nanotechnology actually began in the mid 19teens when the familiar case comes to pass.Certainly, the phrase itself comes with the olden times. The word allocate to this type ofscientific progression known to have originate from a paper that was released in 1974 writtenfrom the Tokyo Science University. There, a student invents the term “nanotechnology” inhis paper and the name fixed firmly from then on. This is one region of this science’s timepast that is not willingly argued, or argument able.At some stage in this time, nanotechnology truly boomed and as early as 1974 there were somany cracks that guided scientist to carry on this science with passion. Discoveries, such asthe famous Finns’ process of atomic layering assist to put nanotechnology on the map whilstit added up to being recognized by the rest of scientific community.In order to exactly manuscript the history of nanotechnology, one could disagree that itstarted when we developed the aptitude to resolve particle size, which is designate to bearound the turn of 20th century.It was during this occasion that particle size became an invariable factor in scientificdiscovery. These dimensions were witness at smaller than 10nm, which in lay terms interpretroughly into less microscopic.Although nanotechnology is a relatively recent development in scientific research, thedevelopment of its central concepts happened over a longer period of time. The emergence ofnanotechnology in the 1980s was caused by the convergence of experimental advances suchas the invention of the scanning tunneling microscope in 1981 and the discovery of fullerenesin 1985, with the elucidation and popularization of a conceptual framework for the goals ofnanotechnology beginning with the 1986 publication of the book Engines of Creation.The 1980s and the early 1990s saw a noteworthy boost in the reputation of nanotechnology.This is the science that can shape out how to strengthen our lives with nothing more thanmolecules and atoms. This is the science where innovations are always turning out and beinganalysed. It won’t be so long before we look to nano, scientist’s effort to fix some of theworlds chubby social difficulties with the execution of technology & progress. K. Eric Drexler developed and popularized the concept of nanotechnology and founded thefield of molecular nanotechnology. In 1979, Drexler encountered Richard Feynmans 1959
  • 4. talk "Theres Plenty of Room at the Bottom". The term "nanotechnology", originally coinedby Norio Taniguchi in 1974, was unknowingly appropriated by Drexler in his 1986 bookEngines of Creation: The Coming Era of Nanotechnology, which proposed the idea of ananoscale "assembler" which would be able to build a copy of itself and of other items ofarbitrary complexity. He also first published the term "grey goo" to describe what mighthappen if a hypothetical self-replicating molecular nanotechnology went out of control.Drexlers vision of nanotechnology is often called "Molecular Nanotechnology" (MNT) or"molecular manufacturing," and Drexler at one point proposed the term "zettatech" whichnever became popular.In the early 2000s, the field was subject to growing public awareness and controversy, withprominent debates about both its potential implications, exemplified by the Royal Societysreport on nanotechnology, as well as the feasibility of the applications envisioned byadvocates of molecular nanotechnology, which culminated in the public debate between EricDrexler and Richard Smalley in 2001 and 2003. Governments moved to promote and fundresearch into nanotechnology with programs such as the National Nanotechnology Initiative.The early 2000s also saw the beginnings of commercial applications of nanotechnology,although these were limited to bulk applications of nanomaterials, such as the Silver Nanoplatform for using silver nanoparticles as an antibacterial agent, nanoparticle-basedtransparent sunscreens, and carbon nanotubes for stain-resistant textiles. FUNDAMENTAL CONCEPT OF NANOTECHNOLOGYNanotechnology is the engineering of functional systems at the molecular scale. This coversboth current work and concepts that are more advanced. In its original sense, nanotechnologyrefers to the projected ability to construct items from the bottom up, using techniques andtools being developed today to make complete, high performance products.One nanometer (nm) is one billionth, or 10−9, of a meter. By comparison, typical carbon-carbon bond lengths, or the spacing between these atoms in a molecule, are in the range 0.12–0.15 nm, and a DNA double-helix has a diameter around 2 nm. On the other hand, thesmallest cellular life-forms, the bacteria of the genus Mycoplasma, are around 200 nm inlength. By convention, nanotechnology is taken as the scale range 1 to 100 nm following thedefinition used by the National Nanotechnology Initiative in the US. The lower limit is set bythe size of atoms (hydrogen has the smallest atoms, which are approximately a quarter of anm diameter) since nanotechnology must build its devices from atoms and molecules. Theupper limit is more or less arbitrary but is around the size that phenomena not observed inlarger structures start to become apparent and can be made use of in the nano device. Thesenew phenomena make nanotechnology distinct from devices which are merely miniaturisedversions of an equivalent macroscopic device; such devices are on a larger scale and comeunder the description of microtechnology.To put that scale in another context, the comparative size of a nanometer to a meter is thesame as that of a marble to the size of the earth. Or another way of putting it: a nanometer isthe amount an average mans beard grows in the time it takes him to raise the razor to hisface.Two main approaches are used in nanotechnology. In the "bottom-up" approach, materialsand devices are built from molecular components which assemble themselves chemically byprinciples of molecular recognition. In the "top-down" approach, nano-objects areconstructed from larger entities without atomic-level control.
  • 5. MOLECULAR NANOTECHNOLOGYMolecular nanotechnology, sometimes called molecular manufacturing, describes engineerednanosystems (nanoscale machines) operating on the molecular scale. Molecularnanotechnology is especially associated with the molecular assembler, a machine that canproduce a desired structure or device atom-by-atom using the principles of mechanosynthesis.Manufacturing in the context of productive nanosystems is not related to, and should beclearly distinguished from, the conventional technologies used to manufacture nanomaterialssuch as carbon nanotubes and nanoparticles.When the term "nanotechnology" was independently coined and popularized by Eric Drexler(who at the time was unaware of an earlier usage by Norio Taniguchi) it referred to a futuremanufacturing technology based on molecular machine systems. The premise was thatmolecular scale biological analogies of traditional machine components demonstratedmolecular machines were possible: by the countless examples found in biology, it is knownthat sophisticated, stochastically optimised biological machines can be produced. It is hopedthat developments in nanotechnology will make possible their construction by some othermeans, perhaps using biomimetic principles. However, Drexler and other researchers haveproposed that advanced nanotechnology, although perhaps initially implemented bybiomimetic means, ultimately could be based on mechanical engineering principles, namely,a manufacturing technology based on the mechanical functionality of these components (suchas gears, bearings, motors, and structural members) that would enable programmable,positional assembly to atomic specification. The physics and engineering performance ofexemplar designs were analyzed in Drexlers book Nanosystems.In general it is very difficult to assemble devices on the atomic scale, as all one has toposition atoms on other atoms of comparable size and stickiness. Another view, put forth byCarlo Montemagno, is that future nanosystems will be hybrids of silicon technology andbiological molecular machines. Yet another view, put forward by the late Richard Smalley, isthat mechanosynthesis is impossible due to the difficulties in mechanically manipulatingindividual molecules. Fig:- Fullerene and CNT
  • 6. POTENTIAL BENEFITS OF NANOTECHNOLOGYThere are a number of fields in which nanotechnology now a days involving and having itspotential benefits regarding these fields. According to the different researches, thenanotechnology is involved in the manufacturing of new materials, new medical,pharmaceutical, agricultural, environmental processes and procedures, new electronicdevices, new sensors, and new computer technologies. Now a day there is a hugeadvancement is looking the fields of the mobiles where a numerous number of advancementsare coming regarding nanotechnology. Small phones with much more functions are also anapplication to the nanotechnology. Similarly it has increase the number of ways in which ithas capacity to utilize the atomic and molecular possessions of materials to make thediversified new methods and meanings of the producing current products. Due to thistechnology we are able to have overlooked on it more precisely this far-reachingnanotechnology that is now making it one of the most successful and innovative areas ofscience, and one that has the most commercialization about its products and the concept.People now like it due to its convenience, accessibility and attractive smaller designs.The Nanotechnology has an ability to transform the current trends of the manufacturing of theproducts in such a way that is almost impossible to imagine. Nanotechnology is already beingused in our everyday items like sunscreen to needles. And it has also wide application in thefield of architecture that has been appreciated a lot. In the near future, it will take us to usethe building resources like coating, bricks and other essentials things to be developed in sucha way that it will not remain too much complicated. Although by these means and ways, theseinitiatives in the nanotechnology industry can change the future of the human being and it canbe very helpful for us to use these materials very easily and efficiently. Similarly thedevelopment of the carbon nanotubes and other materials related to the building is going tochange the building design and performance relative to previous concepts and areas. Thedevelopment of nanotechnology is offering new combinations of the strength, durability andtoughness that is helpful for the solution to our problems. For example the bio-mimeticmaterials that are based on the structures and compounds present in the nature. And has theability to adjust their interfaces, shape memory, self repairing and to handle strain materials. Fig:- Nanoparticles and atoms
  • 7. TWO MAIN APPROACHES FOR PRODUCING NANOMATERIALSTwo main approaches are used in nanotechnology. In the "bottom-up" approach,materials and devices are built from molecular components which assemble themselveschemically by principles of molecular recognition. In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control.TOP-DOWN APPROACH:Several phenomena become pronounced as the size of the system decreases. These includestatistical mechanical effects, as well as quantum mechanical effects, for example the“quantum size effect” where the electronic properties of solids are altered with greatreductions in particle size. This effect does not come into play by going from macro to microdimensions. However, quantum effects become dominant when the nanometer size range isreached, typically at distances of 100 nanometers or less, the so-called quantum realm.Additionally, a number of physical (mechanical, electrical, optical, etc.) properties changewhen compared to macroscopic systems. One example is the increase in surface area tovolume ratio altering mechanical, thermal and catalytic properties of materials. Diffusion andreactions at nanoscale, nanostructures materials and nanodevices with fast ion transport aregenerally referred to nanoionics. Mechanical properties of nanosystems are of interest in thenanomechanics research. The catalytic activity of nanomaterials also opens potential risks intheir interaction with biomaterials.These seek to create smaller devices by using larger ones to direct their assembly. Many technologies that descended from conventional solid-state silicon methods for fabricating microprocessors are now capable of creating features smaller than 100 nm, falling under the definition of nanotechnology. Giant magnetoresistance-based hard drives already on the market fit this description,[26] as do atomic layer deposition (ALD) techniques. Peter Grünberg and Albert Fert received the Nobel Prize in Physics in 2007 for their discovery of Giant magnetoresistance and contributions to the field of spintronics.[27] Solid-state techniques can also be used to create devices known as nanoelectromechanical systems or NEMS, which are related to microelectromechanical systems or MEMS. Focused ion beams can directly remove material, or even deposit material when suitable pre-cursor gasses are applied at the same time. For example, this technique is used routinely to create sub-100 nm sections of material for analysis in Transmission electron microscopy. Atomic force microscope tips can be used as a nanoscale "write head" to deposit a resist, which is then followed by an etching process to remove material in a top-down method.Materials reduced to the nanoscale can show different properties compared to what theyexhibit on a macroscale, enabling unique applications. For instance, opaque substances
  • 8. become transparent (copper); stable materials turn combustible (aluminum); insolublematerials become soluble (gold). A material such as gold, which is chemically inert at normalscales, can serve as a potent chemical catalyst at nanoscales. Much of the fascination withnanotechnology stems from these quantum and surface phenomena that matter exhibits at thenanoscale.BOTTOM –UP APPROACH:Modern synthetic chemistry has reached the point where it is possible to prepare smallmolecules to almost any structure. These methods are used today to manufacture a widevariety of useful chemicals such as pharmaceuticals or commercial polymers. This abilityraises the question of extending this kind of control to the next-larger level, seekingmethods to assemble these single molecules into supramolecular assemblies consistingof many molecules arranged in a well defined manner.These approaches utilize the concepts of molecular self-assembly and/or supramolecularchemistry to automatically arrange themselves into some useful conformation through abottom-up approach. The concept of molecular recognition is especially important: moleculescan be designed so that a specific configuration or arrangement is favored due to non-covalent intermolecular forces. The Watson–Crick basepairing rules are a direct result of this,as is the specificity of an enzyme being targeted to a single substrate, or the specific foldingof the protein itself. Thus, two or more components can be designed to be complementaryand mutually attractive so that they make a more complex and useful whole.These seek to arrange smaller components into more complex assemblies. DNA nanotechnology utilizes the specificity of Watson–Crick basepairing to construct well-defined structures out of DNA and other nucleic acids. Approaches from the field of "classical" chemical synthesis (inorganic and organic synthesis) also aim at designing molecules with well-defined shape (e.g. bis-peptides). More generally, molecular self-assembly seeks to use concepts of supramolecular chemistry, and molecular recognition in particular, to cause single-molecule components to automatically arrange themselves into some useful conformation. Atomic force microscope tips can be used as a nanoscale "write head" to deposit a chemical upon a surface in a desired pattern in a process called dip pen nanolithography. This technique fits into the larger subfield of nanolithography.Such bottom-up approaches should be capable of producing devices in parallel and be muchcheaper than top-down methods, but could potentially be overwhelmed as the size andcomplexity of the desired assembly increases. Most useful structures require complex andthermodynamically unlikely arrangements of atoms. Nevertheless, there are many examplesof self-assembly based on molecular recognition in biology, most notably Watson–Crickbasepairing and enzyme-substrate interactions. The challenge for nanotechnology is whetherthese principles can be used to engineer new constructs in addition to natural ones.
  • 9. TOOLS AND TECHNIQUES USED IN NANOTECHNOLOGYThere are several important modern developments. The atomic force microscope (AFM) andthe Scanning Tunneling Microscope (STM) are two early versions of scanning probes thatlaunched nanotechnology. There are other types of scanning probe microscopy, all flowingfrom the ideas of the scanning confocal microscope developed by Marvin Minsky in 1961and the scanning acoustic microscope (SAM) developed by Calvin Quate and coworkers inthe 1970s, that made it possible to see structures at the nanoscale.The tip of a scanning probe can also be used to manipulate nanostructures (a process calledpositional assembly). Feature-oriented scanning methodology suggested by Rostislav Lapshinappears to be a promising way to implement these nanomanipulations in automatic mode.However, this is still a slow process because of low scanning velocity of the microscope.Various techniques of nanolithography such as optical lithography, X-ray lithography dip pennanolithography, electron beam lithography or nanoimprint lithography were also developed.Lithography is a top-down fabrication technique where a bulk material is reduced in size tonanoscale pattern.Another group of nanotechnological techniques include those used for fabrication ofnanotubes and nanowires, those used in semiconductor fabrication such as deep ultravioletlithography, electron beam lithography, focused ion beam machining, nanoimprintlithography, atomic layer deposition, and molecular vapor deposition, and further includingmolecular self-assembly techniques such as those employing di-block copolymers. However,all of these techniques preceded the nanotech era, and are extensions in the development ofscientific advancements rather than techniques which were devised with the sole purpose ofcreating nanotechnology and which were results of nanotechnology research.The top-down approach anticipates nanodevices that must be built piece by piece in stages,much as manufactured items are made. Scanning probe microscopy is an important techniqueboth for characterization and synthesis of nanomaterials. Atomic force microscopes andscanning tunneling microscopes can be used to look at surfaces and to move atoms around.By designing different tips for these microscopes, they can be used for carving out structureson surfaces and to help guide self-assembling structures. By using, for example, feature-oriented scanning approach, atoms or molecules can be moved around on a surface withscanning probe microscopy techniques. At present, it is expensive and time-consuming formass production but very suitable for laboratory experimentation.In contrast, bottom-up techniques build or grow larger structures atom by atom or moleculeby molecule. These techniques include chemical synthesis, self-assembly and positionalassembly. Dual polarisation interferometry is one tool suitable for characterisation of selfassembled thin films. Another variation of the bottom-up approach is molecular beam epitaxyor MBE. Researchers at Bell Telephone Laboratories like John R. Arthur. Alfred Y. Cho, andArt C. Gossard developed and implemented MBE as a research tool in the late 1960s and1970s. Samples made by MBE were key to the discovery of the fractional quantum Halleffect for which the 1998 Nobel Prize in Physics was awarded. MBE allows scientists to laydown atomically precise layers of atoms and, in the process, build up complex structures.
  • 10. Important for research on semiconductors, MBE is also widely used to make samples anddevices for the newly emerging field of spintronics.However, new therapeutic products, based on responsive nanomaterials, such as theultradeformable, stress-sensitive Transfersome vesicles, are under development and alreadyapproved for human use in some countries.Fig:- Typical AFM setup. A microfabricated cantilever with a sharp tip is deflected byfeatures on a sample surface, much like in a phonograph but on a much smaller scale. A laserbeam reflects off the backside of the cantilever into a set of photodetectors, allowing thedeflection to be measured and assembled into an image of the surface. Fig:-STM microscope working
  • 11. APPLICATIONS OF NANOTECHNOLOGYAs of August 21, 2008, the Project on Emerging Nanotechnologies estimates that over 800manufacturer-identified nanotech products are publicly available, with new ones hitting themarket at a pace of 3–4 per week. The project lists all of the products in a publicly accessibleonline database. Most applications are limited to the use of "first generation" passivenanomaterials which includes titanium dioxide in sunscreen, cosmetics, surface coatings,[39]and some food products; Carbon allotropes used to produce gecko tape; silver in foodpackaging, clothing, disinfectants and household appliances; zinc oxide in sunscreens andcosmetics, surface coatings, paints and outdoor furniture varnishes; and cerium oxide as afuel catalyst.Further applications allow tennis balls to last longer, golf balls to fly straighter, and evenbowling balls to become more durable and have a harder surface. Trousers and socks havebeen infused with nanotechnology so that they will last longer and keep people cool in thesummer. Bandages are being infused with silver nanoparticles to heal cuts faster.[40] Cars arebeing manufactured with nanomaterials so they may need fewer metals and less fuel tooperate in the future.[41] Video game consoles and personal computers may become cheaper,faster, and contain more memory thanks to nanotechnology. Nanotechnology may have theability to make existing medical applications cheaper and easier to use in places like thegeneral practitioners office and at home.The National Science Foundation (a major distributor for nanotechnology research in theUnited States) funded researcher David Berube to study the field of nanotechnology. Hisfindings are published in the monograph Nano-Hype: The Truth Behind the NanotechnologyBuzz. This study concludes that much of what is sold as “nanotechnology” is in fact arecasting of straightforward materials science, which is leading to a “nanotech industry builtsolely on selling nanotubes, nanowires, and the like” which will “end up with a few suppliersselling low margin products in huge volumes." Further applications which require actualmanipulation or arrangement of nanoscale components await further research. Thoughtechnologies branded with the term nano are sometimes little related to and fall far short ofthe most ambitious and transformative technological goals of the sort in molecularmanufacturing proposals, the term still connotes such ideas. According to Berube, there maybe a danger that a "nano bubble" will form, or is forming already, from the use of the term byscientists and entrepreneurs to garner funding, regardless of interest in the transformativepossibilities of more ambitious and far-sighted work
  • 12. NANOTECHNOLOGY IN VARIOUS FIELDSMEDICINEThe biological and medical research communities have exploited the unique properties ofnanomaterials for various applications (e.g., contrast agents for cell imaging and therapeuticsfor treating cancer). Terms such as biomedical nanotechnology, nanobiotechnology, andnanomedicine are used to describe this hybrid field. Functionalities can be added tonanomaterials by interfacing them with biological molecules or structures. The size ofnanomaterials is similar to that of most biological molecules and structures; therefore,nanomaterials can be useful for both in vivo and in vitro biomedical research andapplications. Thus far, the integration of nanomaterials with biology has led to thedevelopment of diagnostic devices, contrast agents, analytical tools, physical therapyapplications, and drug delivery vehicles.DiagnosticsNanotechnology-on-a-chip is one more dimension of lab-on-a-chip technology. Magneticnanoparticles, bound to a suitable antibody, are used to label specific molecules, structures ormicroorganisms. Gold nanoparticles tagged with short segments of DNA can be used fordetection of genetic sequence in a sample. Multicolor optical coding for biological assays hasbeen achieved by embedding different-sized quantum dots into polymeric microbeads.Nanopore technology for analysis of nucleic acids converts strings of nucleotides directly intoelectronic signatures.Drug deliveryNanotechnology has been a boon for the medical field by delivering drugs to specific cellsusing nanoparticles. The overall drug consumption and side-effects can be loweredsignificantly by depositing the active agent in the morbid region only and in no higher dosethan needed. This highly selective approach reduces costs and human suffering. An examplecan be found in dendrimers and nanoporous materials. Another example is to use block co-polymers, which form micelles for drug encapsulation. They could hold small drug moleculestransporting them to the desired location. Another vision is based on small electromechanicalsystems; nanoelectromechanical systems are being investigated for the active release ofdrugs. Some potentially important applications include cancer treatment with ironnanoparticles or gold shells. A targeted or personalized medicine reduces the drugconsumption and treatment expenses resulting in an overall societal benefit by reducing thecosts to the public health system. Nanotechnology is also opening up new opportunities inimplantable delivery systems, which are often preferable to the use of injectable drugs,because the latter frequently display first-order kinetics (the blood concentration goes uprapidly, but drops exponentially over time). This rapid rise may cause difficulties withtoxicity, and drug efficacy can diminish as the drug concentration falls below the targetedrange.
  • 13. Buckyballs can "interrupt" the allergy/immune response by preventing mast cells (whichcause allergic response) from releasing histamine into the blood and tissues, by binding tofree radicals "dramatically better than any anti-oxidant currently available, such as vitaminE".Tissue engineeringNanotechnology can help reproduce or repair damaged tissue. “Tissue engineering” makesuse of artificially stimulated cell proliferation by using suitable nanomaterial-based scaffoldsand growth factors. For example, bones can be regrown on carbon nanotube scaffolds. Tissueengineering might replace todays conventional treatments like organ transplants or artificialimplants. Advanced forms of tissue engineering may lead to life extension.Fig:- Nano-biotechnology Fig:-Nanotechnology in treating cancer Fig:-Nanotech in medicine
  • 14. INFORMATION AND COMMUNICATIONCurrent high-technology production processes are based on traditional top down strategies,where nanotechnology has already been introduced silently. The critical length scale ofintegrated circuits is already at the nanoscale (50 nm and below) regarding the gate length oftransistors in CPUs or DRAM devices.Memory storageElectronic memory designs in the past have largely relied on the formation of transistors.However, research into crossbar switch based electronics have offered an alternative usingreconfigurable interconnections between vertical and horizontal wiring arrays to create ultrahigh density memories. Two leaders in this area are Nantero which has developed a carbonnanotube based crossbar memory called Nano-RAM and Hewlett-Packard which hasproposed the use of memristor material as a future replacement of Flash memory.Novel semiconductor devicesAn example of such novel devices is based on spintronics.The dependence of the resistanceof a material (due to the spin of the electrons) on an external field is calledmagnetoresistance. This effect can be significantly amplified (GMR - Giant Magneto-Resistance) for nanosized objects, for example when two ferromagnetic layers are separatedby a nonmagnetic layer, which is several nanometers thick (e.g. Co-Cu-Co). The GMR effecthas led to a strong increase in the data storage density of hard disks and made the gigabyterange possible. The so called tunneling magnetoresistance (TMR) is very similar to GMR andbased on the spin dependent tunneling of electrons through adjacent ferromagnetic layers.Both GMR and TMR effects can be used to create a non-volatile main memory forcomputers, such as the so called magnetic random access memory or MRAM.In 1999, the ultimate CMOS transistor developed at the Laboratory for Electronics andInformation Technology in Grenoble, France, tested the limits of the principles of theMOSFET transistor with a diameter of 18 nm (approximately 70 atoms placed side by side).This was almost one tenth the size of the smallest industrial transistor in 2003 (130 nm in2003, 90 nm in 2004, 65 nm in 2005 and 45 nm in 2007). It enabled the theoreticalintegration of seven billion junctions on a €1 coin. However, the CMOS transistor, which wascreated in 1999, was not a simple research experiment to study how CMOS technologyfunctions, but rather a demonstration of how this technology functions now that we ourselvesare getting ever closer to working on a molecular scale. Today it would be impossible tomaster the coordinated assembly of a large number of these transistors on a circuit and itwould also be impossible to create this on an industrial level.[4]Novel optoelectronic devicesIn the modern communication technology traditional analog electrical devices areincreasingly replaced by optical or optoelectronic devices due to their enormous bandwidthand capacity, respectively. Two promising examples are photonic crystals and quantum dots.Photonic crystals are materials with a periodic variation in the refractive index with a latticeconstant that is half the wavelength of the light used. They offer a selectable band gap for thepropagation of a certain wavelength, thus they resemble a semiconductor, but for light or
  • 15. photons instead of electrons. Quantum dots are nanoscaled objects, which can be used,among many other things, for the construction of lasers. The advantage of a quantum dotlaser over the traditional semiconductor laser is that their emitted wavelength depends on thediameter of the dot. Quantum dot lasers are cheaper and offer a higher beam quality thanconventional laser diodes.DisplaysThe production of displays with low energy consumption could be accomplished usingcarbon nanotubes (CNT). Carbon nanotubes are electrically conductive and due to their smalldiameter of several nanometers, they can be used as field emitters with extremely highefficiency for field emission displays (FED). The principle of operation resembles that of thecathode ray tube, but on a much smaller length scale.Quantum computersEntirely new approaches for computing exploit the laws of quantum mechanics for novelquantum computers, which enable the use of fast quantum algorithms. The Quantumcomputer has quantum bit memory space termed "Qubit" for several computations at thesame time. This facility may improve the performance of the older systems. Fig:-MOSFET using nanosized wires Fig:-Nanoelectronics
  • 16. GREEN NANOTECHGoalsGreen Nanotechnology has two goals: producing nanomaterials and products withoutharming the environment or human health, and producing nano-products that providesolutions to environmental problems. It uses existing principles of Green Chemistry andGreen Engineering[2] to make nanomaterials and nano-products without toxic ingredients, atlow temperatures using less energy and renewable inputs wherever possible, and usinglifecycle thinking in all design and engineering stages.In addition to making nanomaterials and products with less impact to the environment, GreenNanotechnology also means using nanotechnology to make current manufacturing processesfor non-nano materials and products more environmentally friendly. For example, nanoscalemembranes can help separate desired chemical reaction products from waste materials.Nanoscale catalysts can make chemical reactions more efficient and less wasteful. Sensors atthe nanoscale can form a part of process control systems, working with nano-enabledinformation systems. Using alternative energy systems, made possible by nanotechnology, isanother way to "green" manufacturing processes.The second goal of Green Nanotechnology involves developing products that benefit theenvironment either directly or indirectly. Nanomaterials or products directly can cleanhazardous waste sites, desalinate water, treat pollutants, or sense and monitor environmentalpollutants. Indirectly, lightweight nanocomposites for automobiles and other means oftransportation could save fuel and reduce materials used for production; nanotechnology-enabled fuel cells and light-emitting diodes (LEDs) could reduce pollution from energygeneration and help conserve fossil fuels; self-cleaning nanoscale surface coatings couldreduce or eliminate many cleaning chemicals; and enhanced battery life could lead to lessmaterial use and less waste. Green Nanotechnology takes a broad systems view ofnanomaterials and products, ensuring that unforeseen consequences are minimized and thatimpacts are anticipated throughout the full life cycle Fig:-Green Nanotech
  • 17. FiltrationA strong influence of photochemistry on waste-water treatment, air purification andenergy storage devices is to be expected. Mechanical or chemical methods can be used foreffective filtration techniques. One class of filtration techniques is based on the use ofmembranes with suitable hole sizes, whereby the liquid is pressed through themembrane. Nanoporous membranes are suitable for a mechanical filtration withextremely small pores smaller than 10 nm (“nanofiltration”) and may be composed ofnanotubes. Nanofiltration is mainly used for the removal of ions or the separation ofdifferent fluids. On a larger scale, the membrane filtration technique is namedultrafiltration, which works down to between 10 and 100 nm. One important field ofapplication for ultrafiltration is medical purposes as can be found in renal dialysis.Magnetic nanoparticles offer an effective and reliable method to remove heavy metalcontaminants from waste water by making use of magnetic separation techniques. Usingnanoscale particles increases the efficiency to absorb the contaminants and iscomparatively inexpensive compared to traditional precipitation and filtration methods.Some water-treatment devices incorporating nanotechnology are already on the market, withmore in development. Low-cost nanostructured separation membranes methods have beenshown to be effective in producing potable water in a recent study.EnergyThe most advanced nanotechnology projects related to energy are: storage, conversion,manufacturing improvements by reducing materials and process rates, energy saving (bybetter thermal insulation for example), and enhanced renewable energy sources.Reduction of energy consumptionA reduction of energy consumption can be reached by better insulation systems, by the use ofmore efficient lighting or combustion systems, and by use of lighter and stronger materials inthe transportation sector. Currently used light bulbs only convert approximately 5% of theelectrical energy into light. Nanotechnological approaches like light-emitting diodes (LEDs)or quantum caged atoms (QCAs) could lead to a strong reduction of energy consumption forillumination.Increasing the efficiency of energy productionTodays best solar cells have layers of several different semiconductors stacked together toabsorb light at different energies but they still only manage to use 40 percent of the Sunsenergy. Commercially available solar cells have much lower efficiencies (15-20%).Nanotechnology could help increase the efficiency of light conversion by usingnanostructures with a continuum of bandgaps.The degree of efficiency of the internal combustion engine is about 30-40% at present.Nanotechnology could improve combustion by designing specific catalysts with maximizedsurface area. In 2005, scientists at the University of Toronto developed a spray-onnanoparticle substance that, when applied to a surface, instantly transforms it into a solarcollector.
  • 18. HEAVY INDUSTRIESAerospaceLighter and stronger materials will be of immense use to aircraft manufacturers, leading toincreased performance. Spacecraft will also benefit, where weight is a major factor.Nanotechnology would help to reduce the size of equipment and thereby decrease fuel-consumption required to get it airborne.Hang gliders may be able to halve their weight while increasing their strength and toughnessthrough the use of nanotech materials. Nanotech is lowering the mass of supercapacitors thatwill increasingly be used to give power to assistive electrical motors for launching hanggliders off flatland to thermal-chasing altitudes.Space operations can also benefit from the use of nanorobots, presented as single devices orforming swarms of larger sets. For the last option, nano-sized technology may be useful forpolishing telescopes with a better accuracy than with existing methods, even in space, or forthe exploration of extraterrestrial bodies, such as the Moon, or Mars.Space exploration can take leverage of nanorobotic swarms to study Earth’s and outer bodies’atmosphere (when existing) or surface, providing more accurate information about theircomposition and distribution. For example, it may enhance our knowledge of the waterdistribution on the Moon’s Poles, providing a better accuracy than the obtained with currentmethods, and thus enabling us a further exploration of the Moon, with the aim to place afuture permanent base.CatalysisChemical catalysis benefits especially from nanoparticles, due to the extremely large surfaceto volume ratio. The application potential of nanoparticles in catalysis ranges from fuel cell tocatalytic converters and photocatalytic devices. Catalysis is also important for the productionof chemicals.The synthesis provides novel materials with tailored features and chemical properties: forexample, nanoparticles with a distinct chemical surrounding (ligands), or specific opticalproperties. In this sense, chemistry is indeed a basic nanoscience. In a short-term perspective,chemistry will provide novel “nanomaterials” and in the long run, superior processes such as“self-assembly” will enable energy and time preserving strategies. In a sense, all chemicalsynthesis can be understood in terms of nanotechnology, because of its ability to manufacturecertain molecules. Thus, chemistry forms a base for nanotechnology providing tailor-mademolecules, polymers, etcetera, as well as clusters and nanoparticles.Platinum nanoparticle are now being considered in the next generation of automotivecatalytic converters because the very high surface area of nanoparticles could reduce theamount of platinum required.[5] However, some concerns have been raised due to experimentsdemonstrating that they will spontaneously combust if methane is mixed with the ambientair.[6] Ongoing research at the Centre National de la Recherche Scientifique (CNRS) inFrance may resolve their true usefulness for catalytic applications. Nanofiltration may come
  • 19. to be an important application, although future research must be careful to investigatepossible toxicity.ConstructionNanotechnology has the potential to make construction faster, cheaper, safer, and morevaried. Automation of nanotechnology construction can allow for the creation of structuresfrom advanced homes to massive skyscrapers much more quickly and at much lower cost. Inthe near future Nanotechnology can be used to sense cracks in foundations of architecture andcan send nanobots to repair them.Nanotechnology and constructionsNanotechnology is one of the most active research areas that encompass a number ofdisciplines Such as electronics, bio-mechanics and coatings including civil engineering andconstruction materials.The use of nanotechnology in construction involves the development of new concept andunderstanding of the hydration of cement particles and the use of nano-size ingredients suchas alumina and silica and other nanoparticles. The manufactures also investigating themethods of manufacturing of nano-cement. If cement with nano-size particles can bemanufactured and processed, it will open up a large number of opportunities in the fields ofceramics, high strength composites and electronic applications. Since at the nanoscale theproperties of the material are different from that of their bulk counter parts. When materialsbecomes nano-sized, the proportion of atoms on the surface increases relative to those insideand this leads to novel properties. Some applications of nanotechnology in construction aredescribe below.Nanoparticles and steelSteel has been widely available material and has a major role in the construction industry.The use of nanotechnology in steel helps to improve the properties of steel. The fatigue,which led to the structural failure of steel due to cyclic loading, such as in bridges ortowers.The current steel designs are based on the reduction in the allowable stress, servicelife or regular inspection regime. This has a significant impact on the life-cycle costs ofstructures and limits the effective use of resources.The Stress risers are responsible forinitiating cracks from which fatigue failure results .The addition of copper nanoparticlesreduces the surface un-evenness of steel which then limits the number of stress risers andhence fatigue cracking. Advancements in this technology using nanoparticles would lead toincreased safety, less need for regular inspection regime and more efficient materials freefrom fatigue issues for construction.The nano-size steel produce stronger steel cables which can be in bridge construction. Alsothese stronger cable material would reduce the costs and period of construction, especially insuspension bridges as the cables are run from end to end of the span. This would require highstrength joints which leads to the need for high strength bolts. The capacity of high strengthbolts is obtained through quenching and tempering. The microstructures of such productsconsist of tempered martensite. When the tensile strength of tempered martensite steelexceeds 1,200 MPa even a very small amount of hydrogen embrittles the grain boundariesand the steel material may fail during use. This phenomenon, which is known as delayed
  • 20. fracture, which hindered the strengthening of steel bolts and their highest strength is limitedto only around 1,000 to 1,200 MPa.The use of vanadium and molybdenum nanoparticles improves the delayed fracture problemsassociated with high strength bolts reducing the effects of hydrogen embrittlement andimproving the steel micro-structure through reducing the effects of the inter-granularcementite phase.Welds and the Heat Affected Zone (HAZ) adjacent to welds can be brittle and fail withoutwarning when subjected to sudden dynamic loading.The addition of nanoparticles ofmagnesium and calcium makes the HAZ grains finer in plate steel and this leads to anincrease in weld toughness. The increase in toughness at would result in a smaller resourcerequirement because less material is required in order to keep stresses within allowablelimits.The carbon nanotubes are exciting material with tremendous properties of strength andstiffness, they have found little application as compared to steel,because it is difficult to bindthem with bulk material and they pull out easily, Which make them ineffective inconstruction materials.Nanoparticles in glassGlass is also an important material in construction. Research is being carried out on theapplication of nanotechnology to glass. Titanium dioxide (TiO2) nanoparticles are used tocoat glazing since it has sterilizing and anti-fouling properties. The particles catalyzepowerful reactions which break down organic pollutants, volatile organic compounds andbacterial membranes. The TiO2 is hydrophilic (attraction to water) which can attract raindrops which then wash off the dirt particles. Thus the introduction of nanotechnology in theGlass industry, incorporates the self cleaning property of glass.Fire-protective glass is another application of nanotechnology. This is achieved by using aclear intumescent layer sandwiched between glass panels (an interlayer) formed of silicananoparticles (SiO2) which turns into a rigid and opaque fire shield when heated. Most ofglass in construction is on the exterior surface of buildings. So the light and heat entering thebuilding through glass has to be prevented. The nanotechnology can provide a better solutionto block light and heat coming through windows.Nanoparticles in fire protection and detectionFire resistance of steel structures is often provided by a coating produced by a spray-on-cementitious process.The nano-cement has the potential to create a new paradigm in this areaof application because the resulting material can be used as a tough, durable, hightemperature coating. It provides a good method of increasing fire resistance and this is acheaper option than conventional insulation.Vehicle manufacturersMuch like aerospace, lighter and stronger materials will be useful for creating vehicles thatare both faster and safer. Combustion engines will also benefit from parts that are more hard-wearing and more heat-resistant.
  • 21. IMPLICATIONS AND REGULATIONS IN NANOTECHImplicationsThe Center for Responsible Nanotechnology warns of the broad societal implications ofuntraceable weapons of mass destruction, networked cameras for use by the government, andweapons developments fast enough to destabilize arms races.Another area of concern is the effect that industrial-scale manufacturing and use ofnanomaterials would have on human health and the environment, as suggested bynanotoxicology research. For these reasons, groups such as the Center for ResponsibleNanotechnology advocate that nanotechnology be regulated by governments. Others counterthat overregulation would stifle scientific research and the development of beneficialinnovations. Public health research agencies, such as the National Institute for OccupationalSafety and Health are actively conducting research on potential health effects stemming fromexposures to nanoparticles.Some nanoparticle products may have unintended consequences. Researchers havediscovered that bacteriostatic silver nanoparticles used in socks to reduce foot odor are beingreleased in the wash. These particles are then flushed into the waste water stream and maydestroy bacteria which are critical components of natural ecosystems, farms, and wastetreatment processes.Public deliberations on risk perception in the US and UK carried out by the Center forNanotechnology in Society found that participants were more positive aboutnanotechnologies for energy applications than for health applications, with healthapplications raising moral and ethical dilemmas such as cost and availability.Experts, including director of the Woodrow Wilson Centers Project on EmergingNanotechnologies David Rejeski, have testified that successful commercialization depends onadequate oversight, risk research strategy, and public engagement. Berkeley, California iscurrently the only city in the United States to regulate nanotechnology; Cambridge,Massachusetts in 2008 considered enacting a similar law, but ultimately rejected it.Relevantfor both research on and application of nanotechnologies, the insurability of nanotechnologyis contested. Without state regulation of nanotechnology, the availability of private insurancefor potential damages is seen as necessary to ensure that burdens are not socialised implicitly.Health and environmental concernsResearchers have found that when rats breathed in nanoparticles, the particles settled in thebrain and lungs, which led to significant increases in biomarkers for inflammation and stressresponse and that nanoparticles induce skin aging through oxidative stress in hairless mice.A two-year study at UCLAs School of Public Health found lab mice consuming nano-titanium dioxide showed DNA and chromosome damage to a degree "linked to all the bigkillers of man, namely cancer, heart disease, neurological disease and aging".
  • 22. A major study published more recently in Nature Nanotechnology suggests some forms ofcarbon nanotubes – a poster child for the “nanotechnology revolution” – could be as harmfulas asbestos if inhaled in sufficient quantities. Anthony Seaton of the Institute of OccupationalMedicine in Edinburgh, Scotland, who contributed to the article on carbon nanotubes said"We know that some of them probably have the potential to cause mesothelioma. So thosesorts of materials need to be handled very carefully." In the absence of specific regulationforthcoming from governments, Paull and Lyons (2008) have called for an exclusion ofengineered nanoparticles in food. A newspaper article reports that workers in a paint factorydeveloped serious lung disease and nanoparticles were found in their lungs.[61]Extremely small fibers, so called nanofibers, can be as harmful for the lungs as asbestos is.This scientists warn for in the publication "Toxicology Sciences" after experiments with mice.Nanofibers are used in several areas and in different products, in everything from aircraftwings to tennis rackets. In experiments the scientists have seen how mice breathed nanofibersof silver. Fibers larger than 5 micrometer were capsuled in the lungs where they causedinflammations(a precursor for cancer[64] like mesothelioma).RegulationCalls for tighter regulation of nanotechnology have occurred alongside a growing debaterelated to the human health and safety risks of nanotechnology. There is significant debateabout who is responsible for the regulation of nanotechnology. Some regulatory agenciescurrently cover some nanotechnology products and processes (to varying degrees) – by“bolting on” nanotechnology to existing regulations – there are clear gaps in theseregimes.Davies (2008) has proposed a regulatory road map describing steps to deal with theseshortcomings.Stakeholders concerned by the lack of a regulatory framework to assess and control risksassociated with the release of nanoparticles and nanotubes have drawn parallels with bovinespongiform encephalopathy ("mad cow" disease), thalidomide, genetically modifiedfood,nuclear energy, reproductive technologies, biotechnology, and asbestosis. Dr. AndrewMaynard, chief science advisor to the Woodrow Wilson Center’s Project on EmergingNanotechnologies, concludes that there is insufficient funding for human health and safetyresearch, and as a result there is currently limited understanding of the human health andsafety risks associated with nanotechnology. As a result, some academics have called forstricter application of the precautionary principle, with delayed marketing approval, enhancedlabelling and additional safety data development requirements in relation to certain forms ofnanotechnology.The Royal Society report identified a risk of nanoparticles or nanotubes being released duringdisposal, destruction and recycling, and recommended that “manufacturers of products thatfall under extended producer responsibility regimes such as end-of-life regulations publishprocedures outlining how these materials will be managed to minimize possible human andenvironmental exposure” (p. xiii). Reflecting the challenges for ensuring responsible lifecycle regulation, the Institute for Food and Agricultural Standards has proposed thatstandards for nanotechnology research and development should be integrated acrossconsumer, worker and environmental standards. They also propose that NGOs and othercitizen groups play a meaningful role in the development of these standards.
  • 23. The Center for Nanotechnology in Society has found that people respond differently tonanotechnologies based upon application – with participants in public deliberations morepositive about nanotechnologies for energy than health applications – suggesting that anypublic calls for nano regulations may differ by technology sector.Fig:-Nanotech battery Fig:-Nanotechnologically manufactured DNAFig:-Rotaxane-molecular switch Fig:-Gold as imaged by STM
  • 24. CONCLUSIONNanotechnology gives us an ability to build large numbers of products that are incrediblypowerful by todays standards and easy to carry and handle as compare to the previous agesmachines. For example we can have comparison of pocket pc’s and the frame computers inlast ages. This technology creates both opportunity and risk. In this paper we are discussingdifferent aspects of the nanotachnolgy with our life styles, its history and what would be thefuture of this technology. There are also considered many risk along with the opportunitiesdiscussed above. We have to work more to enhance these opportunities while decreasing thethreats of risks associated with this technology.REFERENCES1.Nanotechnology, http://www.zyvex.com/nano/2.Wikipedia,Google

×