Nanotechnology refers to a field of applied science and technology whose theme is the control of matter on the atomic and molecular scale, generally 100 nanometers or smaller, and the fabrication of devices or materials that lie within that size range. For the song by 311, see Grassroots. Applied science is the application of knowledge from one or more natural scientific History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by A nanometre ( American spelling: nanometer, symbol nm) ( Greek: νάνος nanos dwarf; μετρώ metrό count) is a

Overview

Nanotechnology is a highly multidisciplinary field, drawing from fields such as applied physics, materials science, interface and colloid science, device physics, supramolecular chemistry (which refers to the area of chemistry that focuses on the noncovalent bonding interactions of molecules), self-replicating machines and robotics, chemical engineering, mechanical engineering, biological engineering, and electrical engineering. In Academia, Pedagogy, Physical sciences, Earth sciences, Human sciences and Social sciences Materials Science or Materials Engineering is an interdisciplinary field involving the properties of matter and its applications to various areas of Science and Interface and colloid science is a branch of Chemistry dealing with Colloids Heterogeneous systems consisting of a mechanical mixture of particles between Semiconductor devices are Electronic components that exploit the electronic properties of Semiconductor materials principally Silicon, Germanium Supramolecular chemistry refers to the area of Chemistry that focuses on the Noncovalent bonding interactions of molecules A self-replicating machine is an artificial construct that is theoretically capable of autonomously manufacturing a copy of itself using raw materials taken from its environment See also Robot Robotics is the science and technology of Robots and their design manufacture and application Chemical engineering is the branch of Engineering that deals with the application of Physical science (e Mechanical Engineering is an Engineering discipline that involves the application of principles of physics for analysis Design, Manufacturing Biological Engineering (including Biological systems engineering and Bioengineering) is a form of Biotechnology that uses broad-based Electrical engineering, sometimes referred to as electrical and electronic engineering, is a field of Engineering that deals with the study and application of Grouping of the sciences under the umbrella of "nanotechnology" has been questioned on the basis that there is little actual boundary-crossing between the sciences that operate on the nano-scale. Instrumentation is the only area of technology common to all disciplines; on the contrary, for example pharmaceutical and semiconductor industries do not "talk with each other". Corporations that call their products "nanotechnology" typically market them only to a certain industrial cluster. ^[1]

Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are built from molecular components which assemble themselves chemically by principles of molecular recognition. In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by Self-assembly is a term used to describe processes in which a disordered system of pre-existing components forms an organized structure or pattern as a consequence of specific local The term molecular recognition refers to the specific interaction between two or more Molecules through Noncovalent bonding such as including hydrogen bonding In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control. The impetus for nanotechnology comes from a renewed interest in Interface and Colloid Science, coupled with a new generation of analytical tools such as the atomic force microscope (AFM), and the scanning tunneling microscope (STM). Interface and colloid science is a branch of Chemistry dealing with Colloids Heterogeneous systems consisting of a mechanical mixture of particles between The atomic force microscope (AFM or scanning force microscope (SFM is a very high-resolution type of scanning probe microscope, with demonstrated resolution of fractions Scanning tunneling microscope (STM is a powerful technique for viewing surfaces at the atomic level Combined with refined processes such as electron beam lithography and molecular beam epitaxy, these instruments allow the deliberate manipulation of nanostructures, and lead to the observation of novel phenomena. Electron beam lithography (often abbreviated as e-beam lithography) is the practice of scanning a beam of Electrons in a patterned fashion across a surface covered Molecular beam Epitaxy (MBE, is one of several methods of depositing Single crystals It was invented in the late 1960s at Bell Telephone Laboratories

Examples of nanotechnology are the manufacture of polymers based on molecular structure, and the design of computer chip layouts based on surface science. Microchipsjpg|right|thumb|200px|Microchips ( EPROM memory with a transparent window showing the integrated circuit inside Despite the promise of nanotechnologies such as quantum dots and nanotubes, real commercial applications have mainly used the advantages of colloidal nanoparticles in bulk form, such as suntan lotion, cosmetics, protective coatings, drug delivery,^[2] and stain resistant clothing. A quantum dot is a Semiconductor whose Excitons are confined in all three Spatial dimensions. Sunscreen (also known as sunblock or suntan lotion) is a Lotion, spray or other Topical product that absorbs or reflects the Sun 's An industrial coating is a paint or coating defined by its protective rather than its aesthetic properties although it can provide both Drug delivery is the method or process of administering a

Origins

Buckminsterfullerene C₆₀, also known as the buckyball, is the simplest of the carbon structures known as fullerenes. This is a list of the Allotropes of Carbon. Diamond See also Diamond Diamond is one of the best known allotropes "C60" and "C-60" redirect here For other uses see C60 (disambiguation. Members of the fullerene family are a major subject of research falling under the nanotechnology umbrella.

Main article: History of nanotechnology

The first use of the concepts in 'nano-technology' (but predating use of that name) was in "There's Plenty of Room at the Bottom," a talk given by physicist Richard Feynman at an American Physical Society meeting at Caltech on December 29, 1959. Although Nanotechnology is a relatively recent development in scientific research the development of its central concepts happened over a longer period of time There's Plenty of Room at the Bottom is the title of a famous lecture given by physicist Richard Feynman at an American Physical Society meeting Richard Phillips Feynman (ˈfaɪnmən May 11 1918 – February 15 1988 was an American Physicist known for the Path integral formulation of quantum The American Physical Society was founded in 1899 and is the World 's second largest organization of physicists behind the Deutsche Physikalische Gesellschaft. The California Institute of Technology (commonly referred to as Caltech) is a private, Coeducational research university located in Pasadena Events 1170 - Thomas Becket: Thomas Becket Archbishop of Canterbury is assassinated inside Canterbury Cathedral by followers of King Henry II The year 1959 ( MCMLIX) was a Common year starting on Thursday (link will display full calendar of the Gregorian calendar. Feynman described a process by which the ability to manipulate individual atoms and molecules might be developed, using one set of precise tools to build and operate another proportionally smaller set, so on down to the needed scale. In the course of this, he noted, scaling issues would arise from the changing magnitude of various physical phenomena: gravity would become less important, surface tension and Van der Waals attraction would become more important, etc. The Van der Waals equation is an Equation of state that can be derived from a special form of the potential between a pair of molecules (hard-sphere repulsion This basic idea appears plausible, and exponential assembly enhances it with parallelism to produce a useful quantity of end products. The term "nanotechnology" was defined by Tokyo Science University Professor Norio Taniguchi in a 1974 paper^[3] as follows: "'Nano-technology' mainly consists of the processing of, separation, consolidation, and deformation of materials by one atom or by one molecule. Tokyo University of Science (東京理科大学 Tōkyō Rika Daigaku, formerly "Science University of Tokyo" is a prestigious private university of Science and Technology Norio Taniguchi (谷口紀男 ( 27 May[[ 912]] - 15 November 1999) was a professor of Tokyo Science University. Year 1974 ( MCMLXXIV) was a Common year starting on Tuesday (link will display full calendar of the 1974 Gregorian calendar. " In the 1980s the basic idea of this definition was explored in much more depth by Dr. K. Eric Drexler, who promoted the technological significance of nano-scale phenomena and devices through speeches and the books Engines of Creation: The Coming Era of Nanotechnology (1986) and Nanosystems: Molecular Machinery, Manufacturing, and Computation,^[4] and so the term acquired its current sense. Kim Eric Drexler (born April 25, 1955 in Oakland California) is an American engineer best known for popularizing the potential of Molecular Engines of Creation is a seminal Molecular nanotechnology book written by K Engines of Creation: The Coming Era of Nanotechnology is considered the first book on the topic of nanotechnology. Engines of Creation is a seminal Molecular nanotechnology book written by K Nanotechnology and nanoscience got started in the early 1980s with two major developments; the birth of cluster science and the invention of the scanning tunneling microscope (STM). In physics the term clusters denotes small multiatom particles Scanning tunneling microscope (STM is a powerful technique for viewing surfaces at the atomic level This development led to the discovery of fullerenes in 1986 and carbon nanotubes a few years later. "C60" and "C-60" redirect here For other uses see C60 (disambiguation. See also Graphene, Buckypaper Carbon nanotubes (CNTs are Allotropes of carbon with a nanostructure that can have a length-to-diameter In another development, the synthesis and properties of semiconductor nanocrystals was studied; This led to a fast increasing number of metal oxide nanoparticles of quantum dots. Fahlman B D has described a nanocrystal as any nanomaterial with at least one dimension ≤ 100nm and that is singlecrystalline A quantum dot is a Semiconductor whose Excitons are confined in all three Spatial dimensions. The atomic force microscope was invented six years after the STM was invented. The atomic force microscope (AFM or scanning force microscope (SFM is a very high-resolution type of scanning probe microscope, with demonstrated resolution of fractions In 2000, the United States National Nanotechnology Initiative was founded to coordinate Federal nanotechnology research and development.

Fundamental concepts

One nanometer (nm) is one billionth, or 10^-9 of a meter. To put that scale in context, the comparative size of a nanometer to a meter is the same as that of a marble to the size of the earth. ^[5] Or another way of putting it: a nanometer is the amount a man's beard grows in the time it takes him to raise the razor to his face. ^[5]

Typical carbon-carbon bond lengths, or the spacing between these atoms in a molecule, are in the range 0. In Molecular geometry, bond length or bond distance is the average distance between nuclei of two bonded Atoms in a Molecule. 12-0. 15 nm, and a DNA double-helix has a diameter around 2 nm. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known On the other hand, the smallest cellular lifeforms, the bacteria of the genus Mycoplasma, are around 200 nm in length. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called Mycoplasma is a Genus of bacteria which lack a Cell wall. Without a cell wall they are unaffected by many common Antibiotics such

Larger to smaller: a materials perspective

Image of reconstruction on a clean Au(100) surface, as visualized using scanning tunneling microscopy. Surface reconstruction refers to the process by which Atoms at the surface of a Crystal assume a different structure than that of the bulk Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Miller indices are a notation system in Crystallography for planes and directions in crystal (Bravais lattices In particular a family of Lattice planes Scanning tunneling microscope (STM is a powerful technique for viewing surfaces at the atomic level The positions of the individual atoms composing the surface are visible. History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny

Main article: Nanomaterials

A number of physical phenomena become pronounced as the size of the system decreases. Nanomaterials are application with morphological features smaller than a one tenth of a micrometre in at least one dimension These include statistical mechanical effects, as well as quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with great reductions in particle size. Statistical mechanics is the application of Probability theory, which includes mathematical tools for dealing with large populations to the field of Mechanics Quantum mechanics is the study of mechanical systems whose dimensions are close to the Atomic scale such as Molecules Atoms Electrons This effect does not come into play by going from macro to micro dimensions. However, it becomes dominant when the nanometer size range is reached. Additionally, a number of physical (mechanical, electrical, optical, etc. ) properties change when compared to macroscopic systems. One example is the increase in surface area to volume ratio altering mechanical, thermal and catalytic properties of materials. Novel mechanical properties of nanosystems are of interest in the nanomechanics research. Nanomechanics is a branch of Nanoscience studying fundamental mechanical (elastic thermal and kinetic properties of physical systems at the Nanometer The catalytic activity of nanomaterials also opens potential risks in their interaction with biomaterials. The development of biomaterials is not a new area of Science, having existed for around half a century

Materials reduced to the nanoscale can show different properties compared to what they exhibit on a macroscale, enabling unique applications. For instance, opaque substances become transparent (copper); inert materials become catalysts (platinum); stable materials turn combustible (aluminum); solids turn into liquids at room temperature (gold); insulators become conductors (silicon). A material such as gold, which is chemically inert at normal scales, can serve as a potent chemical catalyst at nanoscales. Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst Much of the fascination with nanotechnology stems from these quantum and surface phenomena that matter exhibits at the nanoscale.

Simple to complex: a molecular perspective

Main article: Molecular self-assembly

Modern synthetic chemistry has reached the point where it is possible to prepare small molecules to almost any structure. Molecular self-assembly is the process by which Molecules adopt a defined arrangement without guidance or management from an outside source In Chemistry, chemical synthesis is purposeful execution of Chemical reactions in order to get a product, or several products In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by These methods are used today to produce a wide variety of useful chemicals such as pharmaceuticals or commercial polymers. A drug, broadly speaking is any chemical substance that when absorbed into the body A polymer is a large Molecule ( Macromolecule) composed of repeating Structural units typically connected by Covalent Chemical bonds This ability raises the question of extending this kind of control to the next-larger level, seeking methods to assemble these single molecules into supramolecular assemblies consisting of many molecules arranged in a well defined manner. A supramolecular assembly or "supermolecule" is a well defined complex of molecules held together by noncovalent bonds.

These approaches utilize the concepts of molecular self-assembly and/or supramolecular chemistry to automatically arrange themselves into some useful conformation through a bottom-up approach. Molecular self-assembly is the process by which Molecules adopt a defined arrangement without guidance or management from an outside source Supramolecular chemistry refers to the area of Chemistry that focuses on the Noncovalent bonding interactions of molecules The concept of molecular recognition is especially important: molecules can be designed so that a specific conformation or arrangement is favored due to non-covalent intermolecular forces. The term molecular recognition refers to the specific interaction between two or more Molecules through Noncovalent bonding such as including hydrogen bonding A noncovalent bond is a type of Chemical bond, typically between Macromolecules that does not involve the sharing of pairs of electrons but rather involves more dispersed In Physics, Chemistry, and Biology, intermolecular forces are forces that act between stable Molecules or between functional groups of 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 folding of the protein itself. In Molecular biology, two Nucleotides on opposite complementary DNA or RNA strands that are connected via Hydrogen bonds are called Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins Protein folding is the physical process by which a Polypeptide folds into its characteristic and functional three-dimensional structure. Thus, two or more components can be designed to be complementary and mutually attractive so that they make a more complex and useful whole.

Such bottom-up approaches should be able to produce devices in parallel and much cheaper than top-down methods, but could potentially be overwhelmed as the size and complexity of the desired assembly increases. Most useful structures require complex and thermodynamically unlikely arrangements of atoms. Nevertheless, there are many examples of self-assembly based on molecular recognition in biology, most notably Watson-Crick basepairing and enzyme-substrate interactions. Foundations of modern biology There are five unifying principles In Molecular biology, two Nucleotides on opposite complementary DNA or RNA strands that are connected via Hydrogen bonds are called Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins The challenge for nanotechnology is whether these principles can be used to engineer novel constructs in addition to natural ones.

Molecular nanotechnology: a long-term view

Main article: Molecular nanotechnology

Molecular nanotechnology, sometimes called molecular manufacturing, is a term given to the concept of engineered nanosystems (nanoscale machines) operating on the molecular scale. Molecular nanotechnology (MNT is the concept of engineering functional mechanical systems at the molecular scale It is especially associated with the concept of a molecular assembler, a machine that can produce a desired structure or device atom-by-atom using the principles of mechanosynthesis. A molecular assembler as defined by K Eric Drexler is a "proposed device able to guide chemical reactions by positioning reactive molecules with atomic precision Mechanosynthesis in Chemistry is any Chemical synthesis that takes place by mechanical forces alone Manufacturing in the context of productive nanosystems is not related to, and should be clearly distinguished from, the conventional technologies used to manufacture nanomaterials such as carbon nanotubes and nanoparticles. The Technology Roadmap for Productive Nanosystems defines " productive nanosystems " as functional Nanometer -scale Systems that make Atomically

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 future manufacturing technology based on molecular machine systems. Kim Eric Drexler (born April 25, 1955 in Oakland California) is an American engineer best known for popularizing the potential of Molecular Although Nanotechnology is a relatively recent development in scientific research the development of its central concepts happened over a longer period of time Norio Taniguchi (谷口紀男 ( 27 May[[ 912]] - 15 November 1999) was a professor of Tokyo Science University. A molecular machine has been defined as a discrete number of molecular components that have been designed to perform mechanical-like movements (output in response to specific stimuli The premise was that molecular-scale biological analogies of traditional machine components demonstrated molecular machines were possible: by the countless examples found in biology, it is known that sophisticated, stochastically optimised biological machines can be produced. Stochastic (from the Greek "Στόχος" for "aim" or "guess" means Random. .

It is hoped that developments in nanotechnology will make possible their construction by some other means, perhaps using biomimetic principles. Bionics (also known as biomimetics, biognosis, Biomimicry, or bionical creativity engineering) is the application of biological However, Drexler and other researchers^[6] have proposed that advanced nanotechnology, although perhaps initially implemented by biomimetic means, ultimately could be based on mechanical engineering principles, namely, a manufacturing technology based on the mechanical functionality of these components (such as gears, bearings, motors, and structural members) that would enable programmable, positional assembly to atomic specification (PNAS-1981). The physics and engineering performance of exemplar designs were analyzed in Drexler's book Nanosystems.

But Drexler's analysis is very qualitative and does not address very pressing issues, such as the "fat fingers" and "Sticky fingers" problems. In general it is very difficult to assemble devices on the atomic scale, as all one has to position atoms are other atoms of comparable size and stickyness. Another view, put forth by Carlo Montemagno,^[7] is that future nanosystems will be hybrids of silicon technology and biological molecular machines. Yet another view, put forward by the late Richard Smalley, is that mechanosynthesis is impossible due to the difficulties in mechanically manipulating individual molecules. Richard Errett Smalley ( June 6, 1943 – October 28, 2005) was the Gene and Norman Hackerman Professor of Chemistry

This led to an exchange of letters in the ACS publication Chemical & Engineering News in 2003. The American Chemical Society ( ACS) is a Learned society ( Professional association) based in the United States that supports scientific inquiry Chemical & Engineering News is a weekly chemistry news magazine published by the American Chemical Society. ^[8] Though biology clearly demonstrates that molecular machine systems are possible, non-biological molecular machines are today only in their infancy. Leaders in research on non-biological molecular machines are Dr. Alex Zettl and his colleagues at Lawrence Berkeley Laboratories and UC Berkeley. Alex Zettl is an American condensed matter phyicist He is currently a professor at the University of California Berkeley, where he works on nanoscale devices including They have constructed at least three distinct molecular devices whose motion is controlled from the desktop with changing voltage: a nanotube nanomotor, a molecular actuator, and a nanoelectromechanical relaxation oscillator. A nanomotor is a molecular device capable of converting energy into movement

An experiment indicating that positional molecular assembly is possible was performed by Ho and Lee at Cornell University in 1999. They used a scanning tunneling microscope to move an individual carbon monoxide molecule (CO) to an individual iron atom (Fe) sitting on a flat silver crystal, and chemically bound the CO to the Fe by applying a voltage.

Current research

Graphical representation of a rotaxane, useful as a molecular switch. A rotaxane is a mechanically-interlocked molecular architecture consisting of a "dumbbell shaped molecule" which is threaded through a " Macrocycle

This device transfers energy from nano-thin layers of quantum wells to nanocrystals above them, causing the nanocrystals to emit visible light. A quantum well is a Potential well that confines particles which were originally free to move in three dimensions to two dimensions forcing them to occupy a planar region Fahlman B D has described a nanocrystal as any nanomaterial with at least one dimension ≤ 100nm and that is singlecrystalline ^[9]

Nanomaterials

This includes subfields which develop or study materials having unique properties arising from their nanoscale dimensions. ^[10]

• Interface and Colloid Science has given rise to many materials which may be useful in nanotechnology, such as carbon nanotubes and other fullerenes, and various nanoparticles and nanorods. Interface and colloid science is a branch of Chemistry dealing with Colloids Heterogeneous systems consisting of a mechanical mixture of particles between See also Graphene, Buckypaper Carbon nanotubes (CNTs are Allotropes of carbon with a nanostructure that can have a length-to-diameter "C60" and "C-60" redirect here For other uses see C60 (disambiguation. In Nanotechnology, a particle is defined as a small object that behaves as a whole unit in terms of its transport and properties In Nanotechnology, nanorods are one morphology of nanoscale objects
• Nanoscale materials can also be used for bulk applications; most present commercial applications of nanotechnology are of this flavor. Nanomaterials are application with morphological features smaller than a one tenth of a micrometre in at least one dimension
• Progress has been made in using these materials for medical applications; see Nanomedicine. Nanomedicine is the medical application of Nanotechnology. The approaches to nanomedicine range from the medical use of Nanomaterials, to nanoelectronic

Bottom-up approaches

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. DNA nanotechnology is a subfield of Nanotechnology which seeks to use the unique Molecular recognition properties of DNA and other Nucleic acids In Molecular biology, two Nucleotides on opposite complementary DNA or RNA strands that are connected via Hydrogen bonds are called Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known A nucleic acid is a Macromolecule composed of chains of monomeric Nucleotides In Biochemistry these Molecules carry Genetic information
• Approaches from the field of "classical" chemical synthesis also aim at designing molecules with well-defined shape (e. g. bis-peptides^[11]). Bis-peptides are analogues of Peptides but consist of Bis-amino acids which bear two Carboxyl groups and two Amino groups The connection of specific
• 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. Molecular self-assembly is the process by which Molecules adopt a defined arrangement without guidance or management from an outside source Supramolecular chemistry refers to the area of Chemistry that focuses on the Noncovalent bonding interactions of molecules The term molecular recognition refers to the specific interaction between two or more Molecules through Noncovalent bonding such as including hydrogen bonding

Top-down approaches

These seek to create smaller devices by using larger ones to direct their assembly.

• Many technologies 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. Semiconductor device fabrication is the process used to create chips the Integrated circuits that are present in everyday Electrical and electronic A microprocessor incorporates most or all of the functions of a Central processing unit (CPU on a single Integrated Giant magnetoresistance-based hard drives already on the market fit this description,^[12] as do atomic layer deposition (ALD) techniques. Giant magnetoresistance (GMR is a quantum mechanical effect a type of Magnetoresistance effect observed in thin film structures composed of alternating Ferromagnetic Atomic Layer Deposition (ALD is a gas phase Chemical process used to create extremely thin coatings Peter Grünberg and Albert Fert received the Nobel Prize in Physics for their discovery of Giant magnetoresistance and contributions to the field of spintronics in 2007. Peter Andreas Grünberg ( May 18, 1939) is a German Physicist, and Nobel Prize in Physics laureate for his coincidental Albert Fert (born March 7 1938) is a French physicist and one of the discoverers of Giant magnetoresistance which brought about The Nobel Prize in Physics (Nobelpriset i fysik is awarded once a year by the Royal Swedish Academy of Sciences. ^[13]

• Solid-state techniques can also be used to create devices known as nanoelectromechanical systems or NEMS, which are related to microelectromechanical systems or MEMS. Nanoelectromechanical systems or NEMS are similar to Microelectromechanical systems (MEMS but smaller Microelectromechanical systems ( MEMS) is the technology of the very small and merges at the nano-scale into Nanoelectromechanical systems (NEMS and Nanotechnology
• 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. The atomic force microscope (AFM or scanning force microscope (SFM is a very high-resolution type of scanning probe microscope, with demonstrated resolution of fractions Dip Pen Nanolithography (DPN is a Scanning probe lithography technique where an Atomic force microscope tip is used to transfer molecules to a surface via a This fits into the larger subfield of nanolithography. Nanolithography — or Photolithography at the Nanometer scale — refers to the fabrication of nanometer-scale structures, meaning patterns with at

Functional approaches

These seek to develop components of a desired functionality without regard to how they might be assembled.

• Molecular electronics seeks to develop molecules with useful electronic properties. For quantum mechanical study of the Electron distribution in a molecule see Stereoelectronics. These could then be used as single-molecule components in a nanoelectronic device. ^[14] For an example see rotaxane. A rotaxane is a mechanically-interlocked molecular architecture consisting of a "dumbbell shaped molecule" which is threaded through a " Macrocycle
• Synthetic chemical methods can also be used to create synthetic molecular motors, such as in a so-called nanocar. Synthetic molecular motors are Molecular machines capable of rotation under energy input The nanocar is a molecule designed in 2005 at Rice University in the group of Professor James Tour.

Speculative

These subfields seek to anticipate what inventions nanotechnology might yield, or attempt to propose an agenda along which inquiry might progress. Futures Studies, Foresight, or Futurology is the science art and practice of postulating possible probable and preferable futures and the worldviews These often take a big-picture view of nanotechnology, with more emphasis on its societal implications than the details of how such inventions could actually be created. The implications of Nanotechnology run the gamut of human affairs from the medical, Ethical, Mental, legal and environmental to fields

• Molecular nanotechnology is a proposed approach which involves manipulating single molecules in finely controlled, deterministic ways. Molecular nanotechnology (MNT is the concept of engineering functional mechanical systems at the molecular scale This is more theoretical than the other subfields and is beyond current capabilities.
• Nanorobotics centers on self-sufficient machines of some functionality operating at the nanoscale. Nanorobotics is the technology of creating machines or Robots at or close to the microscopic scale of a Nanometres (10-9 Metres. There are hopes for applying nanorobots in medicine^[15][16][17], but it may not be easy to do such a thing because of several drawbacks of such devices. ^[18] Nevertheless, progress on innovative materials and methodologies has been demonstrated with some patents granted about new nanomanufacturing devices for future commercial applications, which also progressively helps in the development towards nanorobots with the use of embedded nanobioelectronics concept. ^[19][20]
• Programmable matter based on artificial atoms seeks to design materials whose properties can be easily and reversibly externally controlled. Programmable matter is a term originally coined in 1991 by Toffoli andMargolus to refer to an ensemble of fine-grained computing elementsarranged in space. The term Artificial atom is commonly used to describe objects that have bound discrete electronic states as is the case with naturally occurring atoms
• Due to the popularity and media exposure of the term nanotechnology, the words picotechnology and femtotechnology have been coined in analogy to it, although these are only used rarely and informally. The term picotechnology is a neologism intended to parallel the term Nanotechnology. Femtotechnology is a term used by some futurists to refer to structuring of matter on a Femto[[meter]] scale by analogy with Nanotechnology and Picotechnology

Tools and techniques

Typical AFM setup. The atomic force microscope (AFM or scanning force microscope (SFM is a very high-resolution type of scanning probe microscope, with demonstrated resolution of fractions A microfabricated cantilever with a sharp tip is deflected by features on a sample surface, much like in a phonograph but on a much smaller scale. Microfabrication or micromanufacturing are the terms to describe processes of fabrication of miniature structures of Micrometre sizes and smaller A cantilever is a beam supported on only one end The beam carries the load to the support where it is resisted by moment and Shear stress. The phonograph, or gramophone, was the most common device for playing recorded Sound from the 1870s through the 1980s A laser beam reflects off the backside of the cantilever into a set of photodetectors, allowing the deflection to be measured and assembled into an image of the surface. A laser is a device that emits Light ( Electromagnetic radiation) through a process called Stimulated emission. Photosensors or photodetectors are Sensors of Light or other Electromagnetic energy

The first observations and size measurements of nano-particles were made during the first decade of the 20th century. They are mostly associated with the name of Zsigmondy who made detailed studies of gold sols and other nanomaterials with sizes down to 10 nm and less. He published a book in 1914. ^[21] He used ultramicroscope that employs a dark field method for seeing particles with sizes much less than light wavelength. The ultramicroscope is a system of illumination for extremely small objects such as Colloidal particles Fog droplets or Smoke particles Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency.

There are traditional techniques developed during 20th century in Interface and Colloid Science for characterizing nanomaterials. Interface and colloid science is a branch of Chemistry dealing with Colloids Heterogeneous systems consisting of a mechanical mixture of particles between These are widely used for first generation passive nanomaterials specified in the next section.

These methods include several different techniques for characterizing particle size distribution. The particle size distribution (PSD of a powder or granular material or particles dispersed in fluid is a list of values or a mathematical function that defines the relative amounts This characterization is imperative because many materials that are expected to be nano-sized are actually aggregated in solutions. Some of methods are based on light scattering. Scattering is a general physical process whereby some forms of Radiation, such as Light, Sound or moving particles for example are forced to deviate from Other apply ultrasound, such as ultrasound attenuation spectroscopy for testing concentrated nano-dispersions and microemulsions. Not to be confused with Supersonic. Ultrasound is cyclic Sound pressure with a Frequency greater than the upper Ultrasound attenuation spectroscopy is a method for characterizing properties of Fluids and Dispersed particles. ^[22]

There is also a group of traditional techniques for characterizing surface charge or zeta potential of nano-particles in solutions. Surface charge is the Electric charge present at an interface, for instance on the Surface of a Semiconductor material or for example on the Zeta potential is an abbreviation for Electrokinetic potential in colloidal systems. These information is required for proper system stabilzation, preventing its aggregation or flocculation. Flocculation is a process where a Solute comes out of Solution in the form of floc or flakes These methods include microelectrophoresis, electrophoretic light scattering and electroacoustics. Microelectrophoresis is a method of studying Electrophoresis of various Dispersed particles using Optical Microscopy. Electrophoretic light scattering is based on Dynamic light scattering. The last one, for instance colloid vibration current method is suitable for characterizing concentrated systems. Colloid vibration current is an electroacoustic phenomenon that arises when Ultrasound propagates through a Fluid that contain Ions and either

Next group of nanotechnological techniques include those used for fabrication of nanowires, those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, focused ion beam machining, nanoimprint lithography, atomic layer deposition, and molecular vapor deposition, and further including molecular self-assembly techniques such as those employing di-block copolymers. Focused ion beam, also known as FIB, is a technique used particularly in the semiconductor and materials science fields for site-specific analysis deposition and ablation of However, all of these techniques preceded the nanotech era, and are extensions in the development of scientific advancements rather than techniques which were devised with the sole purpose of creating nanotechnology and which were results of nanotechnology research.

There are several important modern developments. The atomic force microscope (AFM) and the Scanning Tunneling Microscope (STM) are two early versions of scanning probes that launched nanotechnology. The atomic force microscope (AFM or scanning force microscope (SFM is a very high-resolution type of scanning probe microscope, with demonstrated resolution of fractions Scanning tunneling microscope (STM is a powerful technique for viewing surfaces at the atomic level There are other types of scanning probe microscopy, all flowing from the ideas of the scanning confocal microscope developed by Marvin Minsky in 1961 and the scanning acoustic microscope (SAM) developed by Calvin Quate and coworkers in the 1970s, that made it possible to see structures at the nanoscale. Scanning probe microscopy (SPM is a branch of Microscopy that forms images of surfaces using a physical probe that scans the specimen Confocal microscopy is an optical imaging technique used to increase Micrograph contrast and/or to Reconstruct three-dimensional Images by Marvin Lee Minsky (born August 9, 1927) is an American cognitive scientist in the field of Artificial intelligence (AI co-founder A Scanning Acoustic Microscope ( SAM) is a device which uses focused sound to investigate measure or image an object (a process called Scanning Acoustic Tomography Calvin F Quate (born 7 December 1923) is one of the inventors of the Atomic force microscope. The tip of a scanning probe can also be used to manipulate nanostructures (a process called positional assembly). Feature-oriented scanning-positioning methodology suggested by Rostislav Lapshin appears to be a promising way to implement these nanomanipulations in automatic mode. Feature-oriented scanning (FOS is a method intended for high-precision measurement of nanotopography as well as other surface properties and characteristics on a scanning probe Feature-oriented positioning (FOP is a method of precise movement of a scanning microscope probe across the surface under investigation However, this is still a slow process because of low scanning velocity of the microscope. Various techniques of nanolithography such as dip pen nanolithography, electron beam lithography or nanoimprint lithography were also developed. Nanolithography — or Photolithography at the Nanometer scale — refers to the fabrication of nanometer-scale structures, meaning patterns with at Dip Pen Nanolithography (DPN is a Scanning probe lithography technique where an Atomic force microscope tip is used to transfer molecules to a surface via a Electron beam lithography (often abbreviated as e-beam lithography) is the practice of scanning a beam of Electrons in a patterned fashion across a surface covered Nanoimprint lithography is a novel method of fabricating nanometer scale patterns Lithography is a top-down fabrication technique where a bulk material is reduced in size to nanoscale pattern.

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 technique both for characterization and synthesis of nanomaterials. Scanning probe microscopy (SPM is a branch of Microscopy that forms images of surfaces using a physical probe that scans the specimen Atomic force microscopes and scanning tunneling microscopes can be used to look at surfaces and to move atoms around. The atomic force microscope (AFM or scanning force microscope (SFM is a very high-resolution type of scanning probe microscope, with demonstrated resolution of fractions Scanning tunneling microscope (STM is a powerful technique for viewing surfaces at the atomic level By designing different tips for these microscopes, they can be used for carving out structures on surfaces and to help guide self-assembling structures. By using, for example, feature-oriented scanning-positioning approach, atoms can be moved around on a surface with scanning probe microscopy techniques. Feature-oriented scanning (FOS is a method intended for high-precision measurement of nanotopography as well as other surface properties and characteristics on a scanning probe Feature-oriented positioning (FOP is a method of precise movement of a scanning microscope probe across the surface under investigation At present, it is expensive and time-consuming for mass production but very suitable for laboratory experimentation.

In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include chemical synthesis, self-assembly and positional assembly. In Chemistry, chemical synthesis is purposeful execution of Chemical reactions in order to get a product, or several products Self-assembly is a term used to describe processes in which a disordered system of pre-existing components forms an organized structure or pattern as a consequence of specific local Another variation of the bottom-up approach is molecular beam epitaxy or MBE. Molecular beam Epitaxy (MBE, is one of several methods of depositing Single crystals It was invented in the late 1960s at Bell Telephone Laboratories Researchers at Bell Telephone Laboratories like John R. Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) is the Research organization Arthur. Alfred Y. Cho, and Art C. Gossard developed and implemented MBE as a research tool in the late 1960s and 1970s. Samples made by MBE were key to the discovery of the fractional quantum Hall effect for which the 1998 Nobel Prize in Physics was awarded. Year 1998 ( MCMXCVIII) was a Common year starting on Thursday (link will display full 1998 Gregorian calendar) The Nobel Prize in Physics (Nobelpriset i fysik is awarded once a year by the Royal Swedish Academy of Sciences. MBE allows scientists to lay down atomically-precise layers of atoms and, in the process, build up complex structures. Important for research on semiconductors, MBE is also widely used to make samples and devices for the newly emerging field of spintronics. Spintronics (a Neologism meaning "spin transport electronics" also known as magnetoelectronics is an Emerging technology which exploits the intrinsic

Newer techniques such as Dual Polarisation Interferometry are enabling scientists to measure quantitatively the molecular interactions that take place at the nano-scale. Dual polarisation interferometry ( DPI) is an analytical technique in chemistry that can probe layers adsorbed to the surface of a waveguide by using the Evanescent

Applications

Main article: List of nanotechnology applications

As of April 24, 2008 The Project on Emerging Nanotechnologies claims that over 609 nanotech products exist, with new ones hitting the market at a pace of 3-4 per week. With nanotechnology a large set of materials and improved products rely on a change in the physical properties when the feature sizes are shrunk ^[23] The project lists all of the products in a database. Most applications are limited to the use of "first generation" passive nanomaterials which includes titanium dioxide in sunscreen, cosmetics and some food products; Carbon allotropes used to produce gecko tape; silver in food packaging, clothing, disinfectants and household appliances; zinc oxide in sunscreens and cosmetics, surface coatings, paints and outdoor furniture varnishes; and cerium oxide as a fuel catalyst. ^[24]

The National Science Foundation (a major source of funding for nanotechnology in the United States) funded researcher David Berube to study the field of nanotechnology. The National Science Foundation (NSF is a United States Government agency that supports fundamental Research and Education in all the non-medical His findings are published in the monograph “Nano-Hype: The Truth Behind the Nanotechnology Buzz". This published study (with a foreword by Mihail Roco, Senior Advisor for Nanotechnology at the National Science Foundation) concludes that much of what is sold as “nanotechnology” is in fact a recasting of straightforward materials science, which is leading to a “nanotech industry built solely on selling nanotubes, nanowires, and the like” which will “end up with a few suppliers selling low margin products in huge volumes. Mihail Roco chairs the US National Science and Technology Council 's subcommittee on Nanoscale Science Engineering and Technology (NSET and is Senior Advisor for Nanotechnology " Further applications which require actual manipulation or arrangement of nanoscale components await further research. Though technologies branded with the term 'nano' are sometimes little related to and fall far short of the most ambitious and transformative technological goals of the sort in molecular manufacturing proposals, the term still connotes such ideas. Thus there may be a danger that a "nano bubble" will form, or is forming already, from the use of the term by scientists and entrepreneurs to garner funding, regardless of interest in the transformative possibilities of more ambitious and far-sighted work.

Platinum nanoparticles are now being considered in the next generation of automotive catalytic converters because the very high surface area of nanoparticles could reduce the amount of platinum required. ^[25] However, some concerns have been raised due to experiments demonstrating that they will spontaneously combust if methane is mixed with the ambient air. ^[26] Ongoing research at the Centre National de la Recherche Scientifique(CNRS) in France may resolve their true usefulness for catalytic applications. ^[27] Nanofiltration may come to be an important application, although future research must be careful to investigate possible toxicity. Nanofiltration is a relatively recent membrane process used most often with low Total dissolved solids water such as Surface water and fresh groundwater with the ^[28]

In 1999, the ultimate CMOS transistor developed at the Laboratory for Electronics and Information Technology in Grenoble, France, tested the limits of the principles of the MOSFET 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 in 2003, 90 nm in 2004, 65 nm in 2005 and 45 nm in 2007). It enabled the theoretical integration of seven billion junctions on a €1 coin. However, the CMOS transistor, which was created in 1999, was not a simple research experiment to study how CMOS technology functions, but rather a demonstration of how this technology functions now that we ourselves are getting ever closer to working on a molecular scale. Today it would be impossible to master the coordinated assembly of a large number of these transistors on a circuit and it would also be impossible to create this on an industrial level. ^[29]

Cancer

The small size of nanoparticles endows them with properties that can be very useful in oncology, particularly in imaging. Oncology is the branch of medicine that studies Tumors ( Cancer) and seeks to understand their development diagnosis treatment and prevention Quantum dots (nanoparticles with quantum confinement properties, such as size-tunable light emission), when used in conjunction with MRI (magnetic resonance imaging), can produce exceptional images of tumor sites. These nanoparticles are much brighter than organic dyes and only need one light source for excitation. This means that the use of fluorescent quantum dots could produce a higher contrast image and at a lower cost than today's organic dyes used as contrast media. RadiocontrastIn a medical setting a contrast medium is any Substance that is used to enhance the visibility of structures or fluids within the body

Another nanoproperty, high surface area to volume ratio, allows many functional groups to be attached to a nanoparticle, which can seek out and bind to certain tumor cells. See also Cancer A tumor or tumour is the name for a swelling or lesion formed by an abnormal growth of cells (termed neoplastic Additionally, the small size of nanoparticles (10 to 100 nanometers), allows them to preferentially accumulate at tumor sites (because tumors lack an effective lymphatic drainage system). A very exciting research question is how to make these imaging nanoparticles do more things for cancer. For instance, is it possible to manufacture multifunctional nanoparticles that would detect, image, and then proceed to treat a tumor? This question is under vigorous investigation; the answer to which could shape the future of cancer treatment. ^[30]A promising new cancer treatment that may one day replace radiation and chemotherapy is edging closer to human trials. Kanzius RF therapy attaches microscopic nanoparticles to cancer cells and then "cooks" tumors inside the body with radio waves that heat only the nanoparticles and the adjacent (cancerous) cells. This article is about the inventor John Kanzius For the 15th century theologian see John Cantius.

Health and environmental concerns

Main article: Nanotoxicology

Some of the recently developed nanoparticle products may have unintended consequences. Nanotoxicology is the study of the Toxicity of nanomaterials. Unintended consequences are outcomes that are not (or not limited to what the actor intended in a particular situation Researchers have discovered that silver nanoparticles used in socks to reduce foot odor are being released in the wash with possible negative consequences. ^[31] Silver nanoparticles, which are bacteriostatic, may then destroy beneficial bacteria which are important for breaking down organic matter in waste treatment plants or farms. Bacteriostatic Antibiotics limit the growth of bacteria by interfering with bacterial Protein production DNA replication or other aspects of ^[32]

A study at the University of Rochester found that when rats breathed in nanoparticles, the particles settled in the brain and lungs, which lead to significant increases in biomarkers for inflammation and stress response. The University of Rochester ( U of R UR) is a private, nonsectarian Coeducational Research University located in Rochester ^[33]

A major study published more recently in Nature nanotechnology suggests some forms of carbon nanotubes – a poster child for the “nanotechnology revolution” – could be as harmful as asbestos if inhaled in sufficient quantities. Asbestos is a group of Minerals with long thin fibrous Crystals The word "asbestos" (῾ἀσβεστος is derived from a Greek adjective Anthony Seaton of the Institute of Occupational Medicine 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. See also Graphene, Buckypaper Carbon nanotubes (CNTs are Allotropes of carbon with a nanostructure that can have a length-to-diameter So those sorts of materials need to be handled very carefully. " ^[34]. In the absence of specific nano-regulation forthcoming from governments, Paull and Lyons (2008) have called for an exclusion of engineered nanoparticles from organic food. ^[35]

Implications

Main article: Implications of nanotechnology

Due to the far-ranging claims that have been made about potential applications of nanotechnology, a number of serious concerns have been raised about what effects these will have on our society if realized, and what action if any is appropriate to mitigate these risks. The implications of Nanotechnology run the gamut of human affairs from the medical, Ethical, Mental, legal and environmental to fields

One area of concern is the effect that industrial-scale manufacturing and use of nanomaterials would have on human health and the environment, as suggested by nanotoxicology research. Nanomaterials are application with morphological features smaller than a one tenth of a micrometre in at least one dimension Nanotoxicology is the study of the Toxicity of nanomaterials. Groups such as the Center for Responsible Nanotechnology have advocated that nanotechnology should be specially regulated by governments for these reasons. The Center for Responsible Nanotechnology ( CRN) founded in December 2002 is a non-profit Research and Advocacy organization with a focus Nanosocialism refers generally to an ideology and political movement with the goal of a Socio-economic system in which the research development and use of Others counter that overregulation would stifle scientific research and the development of innovations which could greatly benefit mankind. With nanotechnology a large set of materials and improved products rely on a change in the physical properties when the feature sizes are shrunk

Other experts, including director of the Woodrow Wilson Center's Project on Emerging Nanotechnologies David Rejeski, have testified^[36] that successful commercialization depends on adequate oversight, risk research strategy, and public engagement. The Project on Emerging Nanotechnologies was established in 2005 as a partnership between the Woodrow Wilson International Center for Scholars and the Pew Charitable More recently local municipalities have passed (Berkeley, CA) or are considering (Cambridge, MA) - ordinances requiring nanomaterial manufacturers to disclose the known risks of their products.

The National Institute for Occupational Safety and Health is conducting research on how nanoparticles interact with the body’s systems and how workers might be exposed to nano-sized particles in the manufacturing or industrial use of nanomaterials. The National Institute for Occupational Safety and Health (or NIOSH) is the United States federal agency responsible for conducting research and making recommendations NIOSH offers interim guidelines for working with nanomaterials consistent with the best scientific knowledge. ^[37]

Longer-term concerns center on the implications that new technologies will have for society at large, and whether these could possibly lead to either a post scarcity economy, or alternatively exacerbate the wealth gap between developed and developing nations. Post scarcity or post-scarcity describes a hypothetical form of Economy or Society, often explored in Science fiction, in which things such as The effects of nanotechnology on the society as a whole, on human health and the environment, on trade, on security, on food systems and even on the definition of "human", have not been characterized or politicized.

See also

References

Further reading

• Fritz Allhoff and Patrick Lin (eds. ), Nanotechnology & Society: Current and Emerging Ethical Issues (Dordrecht: Springer, 2008). [1]
• Fritz Allhoff, Patrick Lin, James Moor, and John Weckert (eds. ), Nanoethics: The Ethical and Societal Implications of Nanotechnology (Hoboken: John Wiley & Sons, 2007). [2] [3]
• J. Clarence Davies, EPA and Nanotechnology: Oversight for the 21st Century, Project on Emerging Nanotechnologies, PEN 9, May 2007.
• William Sims Bainbridge: Nanoconvergence: The Unity of Nanoscience, Biotechnology, Information Technology and Cognitive Science, June 27 2007, Prentice Hall, ISBN 0-13-244643-X
• Lynn E. Foster: Nanotechnology: Science, Innovation, and Opportunity, December 21 2005, Prentice Hall, ISBN 0-13-192756-6
• Impact of Nanotechnology on Biomedical Sciences: Review of Current Concepts on Convergence of Nanotechnology With Biology by Herbert Ernest and Rahul Shetty, from AZojono, May 2005.
• Hari Singh Nalwa (2004), Encyclopedia of Nanoscience and Nanotechnology (10-Volume Set), American Scientific Publishers. ISBN 1-58883-001-2
• Michael Rieth and Wolfram Schommers (2006), Handbook of Theoretical and Computational Nanotechnology (10-Volume Set), American Scientific Publishers. ISBN 1-58883-042-X
• Akhlesh Lakhtakia (ed) (2004). The Handbook of Nanotechnology. Nanometer Structures: Theory, Modeling, and Simulation. SPIE Press, Bellingham, WA, USA. ISBN 0-8194-5186-X.  
• Fei Wang & Akhlesh Lakhtakia (eds) (2006). Selected Papers on Nanotechnology -- Theory & Modeling (Milestone Volume 182). SPIE Press, Bellingham, WA, USA. ISBN 0-8194-6354-X.  
• Jumana Boussey, Georges Kamarinos, Laurent Montès (editors) (2003), Towards Nanotechnology, "Nano et Micro Technologies", Hermes Sciences Publ. , Paris, ISBN 2-7462-0858-X.

External links

Portals

• Nanotechnology Now - Nanotechnology news and information portal site
• Nanotechnology at the Open Directory Project
• UnderstandingNano.com - Nanotechnology portal site
• NanoDetails.com - Nanotechnology portal site
• NanoHive@Home - Distributed Computing Project
• Research articles in nanotechnology
• [4] - Minatec, European center for nanatechnologies
• Nanotechnology News center
• [5] - Inventory of consumer products using nanotechnology

Articles

• OnEarth Magazine » Our Silver-Coated Future
• The Ethics and Politics of Nanotechnology, UNESCO brochure on the science, ethics, legal and political issues surrounding nanotechnology
• The new industrial revolution of Nanotechnology

Videos

• VIDEO: Using Nanotechnology to Improve Health in Developing Countries February 27, 2007 at the Woodrow Wilson Center
• VIDEO: Nanotechnology Discussion by the BBC and the Vega Science Trust. The Open Directory Project ( ODP) also known as dmoz (from directory United Nations Educational Scientific and Cultural Organization ( UNESCO) is a specialized agency of the United Nations established on November 16
• 'Nano2Hybrids' Follow an EU Project Video clips of an EU Nanotechnology Research Project.

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