A particular right-handed helical form of DNA (possessing 11 base pairs per turn) which is the form that DNA molecules exist in when they are partially dehydrated. A-form DNA is found in fibres at 75% relative humidity and requires the presence of sodium, potassium or cesium as the counterion. Instead of lying flat, the bases are tilted with respect to the helical axis, and there are more base pairs per turn.
Adsorption is a process that occurs when a gas or liquid solute accumulates on the surface of a solid or, more rarely, a liquid (adsorbent), forming a molecular or atomic film (the adsorbate). It is different from absorption, in which a substance diffuses into a liquid or solid to form a solution. The term sorption encompasses both processes, while desorption is the reverse process.
An ion consists of one or more atoms and carries a unit charge of electricity. Those that are negative ions (hydroxyl and acidic atoms or groups) are called anions (cf. cation).
A general-purpose device for molecular manufacturing, capable of guiding chemical reactions by positioning molecules
The smallest unit of a chemical element, about a third of a nanometer in diameter. Atoms make up molecules and solid objects.
Atomic Force Microscopy / Microscope (AFM)
Atomic force microscopy is a technique for analysing the surface of a rigid material all the way down to the level of the atom.
AFM uses a mechanical probe to magnify surface features up to 100 000 000 times, and produces 3D images of the surface. It is derived from a related technology, called scanning tunnelling microscopy (STM). The difference is that AFM does not require the sample to conduct electricity, whereas STM does.
AFM also works in regular room temperatures, while STM requires special temperature and other conditions.
AFM is being used to understand materials problems in many areas including data storage, telecommunications, biomedicine, chemistry, and aerospace. The atomic force microscope was invented in 1986. It uses various forces that occur when two objects are brought within nanometres of each other.
An AFM can work either when the probe is in contact with a surface, causing a repulsive force, or when it is a few nanometres away, where the force is attractive.
A unit of pressure equal to one million (106) dynes, equivalent to 10 newtons, per square centimetre. This is approximately the pressure exerted by Earth’s atmosphere at sea level.
Miniaturization engineering or MEMS applied to biotechnology or medicine. In BioMEMS the number of materials involved is much larger than in a comparable electronics application. Both instruments and sensors are used in BioMEMS. Applications include: Forensic science (e.g. O.J.s DNA); Clinical diagnostics (e.g. glucose in blood); Product development (e.g. new drug); and Quality control (e.g. pH of swimming pools).
The design of systems, materials, and their functionality to mimic nature. Current examples include layering of materials to achieve the hardness of an abalone shell or understanding why spider silk is stronger than steel.
Building organic and inorganic structures atom-by-atom, or molecule-by-molecule.
Brownian motion in a fluid brings molecules together in various position and orientations. If molecules have suitable complementary surfaces, they can bind, assembling to form a specific structure. Brownian assembly is a less paradoxical name for self-assembly.
Motion of a particle in a fluid owing to thermal agitation.
Carbon black is a powdered form of elemental carbon. The primary use of carbon black is in rubber products, mainly tyres and other automotive products, but also in many other rubber products such as hoses, gaskets and coated fabrics. Much smaller amounts of carbon black are used in inks and paints, plastics and in the manufacture of dry-cell batteries.
A substance that increases the rate of a chemical reaction by reducing the activation energy, but which is left unchanged by the reaction. A catalyst works by providing a convenient surface for the reaction to occur. The reacting particles gather on the catalyst surface and either collide more frequently with each other or more of the collisions result in a reaction between particles because the catalyst can lower the activation energy for the reaction.
An ion consists of one or more atoms and carries a unit charge of electricity. Those that are positively electrified (hydrogen and the metals) are called cations (cf. anion).
A small structural unit, surrounded by a membrane, making up living things.
Chemical Vapour Deposition (CVD)
A technique used to deposit coatings, where chemicals are first vaporized, and then applied using an inert carrier gas such as nitrogen.
The characteristic of a structure (usually a molecule) that makes it impossible to superimpose it on its mirror image.
The physical method of separation in which the components to be separated are distributed between two phases, one of which is stationary while the other moves in a definite direction. Chromatography is a widely used for the separation, identification, and determination of the chemical components in complex mixtures.
Coordinate Measuring Machine
A mixture in which one substance is divided into minute particles (called colloidal particles) and dispersed throughout a second substance. The mixture is also called a colloidal system, colloidal solution, or colloidal dispersion. Colloid science is the study of systems involving small particles of one substance suspended in another. Suspensions in liquids form the basis of a wide variety of systems of scientific and technological importance, including paints, ceramics, cosmetics, agricultural sprays, detergents, soils, biological cells, and many food preparations.
Complementary Metal-Oxide Semiconductor (CMOS)
The semiconductor technology used in the transistors that are manufactured into most of today’s computer microchips.
Combinations of metals, ceramics, polymers, and biological materials that allow multi-functional behaviour. One common practice is reinforcing polymers or ceramics with ceramic fibres to increase strength while retaining light weight and avoiding the brittleness of the monolithic ceramic. Materials used in the body often combine biological and structural functions (e.g., the encapsulation of drugs).
Cathode Ray Tube.
A dendrimer is an artificially manufactured or synthesized molecule built up from branched units called monomers. Such processes involve working on the scale of nanometers. Technically, a dendrimer is a polymer, which is a large molecule comprised of many smaller ones linked together.
A diode is a specialized electronic component with two electrodes called the anode and the cathode. Most diodes are made with semiconductor materials such as silicon, germanium, or selenium. Diodes can be used as rectifiers, signal limiters, voltage regulators, switches, signal modulators, signal mixers, signal demodulators, and oscillators.
Dip Pen Nanolithography
A direct-write soft lithography technique that is used to create nanostructures on a substrate of interest by delivering collections of molecules via capillary transport from an AFM tip to a surface.
DeoxyriboNucleic Acid. DNA is a code used within cells to form proteins.
A purpose built microchip used to identify mutations or alterations in a gene’s DNA.
Derives from surface science and physical chemistry, focuses on fabrication of structures in carbon silicon, and other inorganic materials. Unlike the ‘wet’ technology, ‘dry’ techniques admit use of metals and semiconductors. The active conduction electrons of these materials make them too reactive to operate in a ‘wet’ environment, but these same electrons provide the physical properties that make ‘dry’ nanostructures promising as electronic, magnetic, and optical devices. Another objective is to develop ‘dry’ structures that possess some of the same attributes of the self-assembly that the wet ones exhibit.
Electro Scanning Microscope (ESM)
Used for the study of surface morphology and the determination of the thickness of MBE grown films.
A technique used to optically characterize material types such as semiconductors, dielectrics, metals, organic polymers and plastics in thin films, thin films stacks and in nanostructures. Ellipsometry does not contact or damage samples, and is an ideal and precise measurement technique for determining optical and, hence, physical and chemical properties of materials at the nanoscale. It is most commonly used to accurately measure film thickness and optical properties.
Creation of a 3D design or image on paper or other material.
Molecular machines found in nature made of protein, which can catalyse (speed up) chemical reactions.
Electro Scanning Microscope
ExtraCellular Matrix (ECM)
A complex structural entity surrounding and supporting cells that are found within mammalian tissues. The ECM is often referred to as the connective tissue. The ECM is composed of three major classes of biomolecules: structural proteins (collagen and elastin) specialized proteins (e.g. fibrillin, fibronectin, and laminin); and proteoglycans: (composed of a protein core to which is attached long chains of repeating disaccharide units termed of glycosaminoglycans (GAGs) forming extremely complex high molecular weight components of the ECM).
Billions of bits per second. A measure of bandwidth on a digital data transmission medium such as optical fibre.
The study of the full complement of genes that make up an organism.
High Resolution Transmission Electron Microscopy.
An organic compound that contains only carbon and hydrogen; classified, according to the arrangement of the atoms and the chemical properties of the compounds, as alicyclic, aliphatic, and aromatic; derived mostly from crude petroleum and also from coal tar and plant sources.
An atom or group of atoms in which the number of electrons is different from the number of protons. If the number of electrons is less than the number of protons, the particle is a positive ion, also called a cation. If the number of electrons is greater than the number of protons, the particle is a negative ion, also called an anion.
The name of a nanofabrication technique used to create ultrathin films (monolayers and isolated molecular layers), the end result of which is called a Langmuir-Blodgett film.
LCD (Liquid Crystal Display)
Technology used for displays in notebook and other smaller computers. LCDs allow displays to be much thinner than cathode ray tube technology. LCDs consume much less power because they work on the principle of blocking light rather than emitting it.
LED (Light Emitting Diode)
A semiconductor device that emits visible light when an electric current passes through it. The light is not particularly bright, but in most LEDs it is monochromatic, occurring at a single wavelength. The output from an LED can range from red (at a wavelength of ~700nm) to blue-violet (~400nm).
Lipids are fatty acids and their derivatives, and substances related biosynthetically or functionally to these compounds.
Lithium Ion (Li-Ion) battery
A rechargeable battery with twice the energy capacity of a Nickel-Cadmium battery and greater stability and safety.
A complex large molecule formed from simpler molecules, usually with a diameter ranging from about 100-10 000 angstroms (10-5 to 10-3 mm).
Substance within which something else originates, develops, or is contained.
The study of the melding of AI and electromechanical machines to make machines that are greater than the sum of their parts.
In biology a thin, pliable layer of tissue covering surfaces or separating or connecting regions, structures, or organs of an animal or a plant. In chemistry a membrane is a thin sheet of natural or synthetic material that can be penetrated, especially by liquids or gases. In environmental applications of nanotechnology a membrane can be used as a filter.
Mesoporous materials are porous materials with regularly arranged, uniform mesopores (2-50nm in diameter). Their large surface areas make them useful as adsorbents or catalysts.
MicroElectroMechanical Systems (MEMS)
Technology used to integrate various electro-mechanical functions onto integrated circuits. A typical MEMS device combines a sensor and logic to perform a monitoring function. Examples include sensing devices used to control the deployment of airbags in cars and switching devices used in optical telecommunications cables.
Individually encapsulated small particles.
The science of designing, manufacturing, and formulating devices and processes that deal with volumes of fluid on the order of nanolitres (symbolized nl and representing units of 10-9 litre) or picoliters (symbolized pl and representing units of 10-12 litre).
Also known as an assembler, a molecular assembler is a molecular machine that can build a molecular structure from its component building blocks.
Any system with atomically precise electronic devices of nanometre dimensions, especially if made of discrete molecular parts rather than the continuous materials found in today’s semiconductor devices.
Manufacturing using molecular machinery, giving molecule-by-molecule control of products and by-products via positional chemical synthesis.
A quasi-one-dimensional molecule that can transport charge carriers (electrons or holes) between its ends.
Group of atoms held together by chemical bonds, a molecule is the typical unit manipulated by nanotechnology.
The observation made in 1965 by Gordon Moore, co-founder of Intel, that the number of transistors per square inch on integrated circuits had doubled every 18 months since the integrated circuit was invented. Moore predicted that this trend would continue for the foreseeable future.
Magnetic Resonance Imaging
Multi Walled Nanotubes
A prefix meaning one billionth (1/1 000 000 000).
An ultra-sensitive, ultra-miniaturized array for biomolecular analysis.
Applies the tools and processes of nano/microfabrication to build devices for studying biosystems.
An ultra-fine gas bubble of diameter less than 1μm (1μm=1/1,000,000 m). It usually occurs temporarily in the process of shrinking a micro-bubble, but disappears soon because of its physical lability (constant change). Recently scientists have succeeded in producing stabilized nano-bubbles by collapsing micro-bubbles instantaneously in water containing electrolyte ions.
Polymer/inorganic nanocomposites are composed of two or more physically distinct components with one or more average dimensions smaller than 100nm. From the structural point of view, the role of inorganic filler, usually as particles or fibres, is to provide intrinsic strength and stiffness while the polymer matrix can adhere to and bind the inorganic component so that forces applied to the composite are transmitted evenly to the filler.
A computer made from components (mechanical, electronic, or otherwise) built at the nanometre scale.
Molecular-sized solids formed with a repeating, 3D pattern of atoms or molecules with an equal distance between each part. Nanocrystals are aggregates of anywhere from a few hundred to tens of thousands of atoms that combine into a crystalline form of matter known as a ‘cluster’. Typically around 10nm in diameter, nanocrystals are larger than molecules but smaller than bulk solids and therefore frequently exhibit physical and chemical properties somewhere in-between. Nanocrystals are believed to have potential in optical electronics because of their ability to change the wavelength of light.
NanoElectroMechanical Systems (NEMS)
A generic term to describe nano scale electrical/mechanical devices. Nanoscale MEMS.
Electronics on a nanometre scale, whether made by current techniques or nanotechnology; includes both molecular electronics and nanoscale devices resembling today’s semiconductor devices.
Design and manufacture of devices with dimensions measured in nanometres.
Hollow and solid carbon fibres with lengths on the order of a few microns and widths varying from tens of nanometres to around 200nm.
Controlling nanoscale amounts of fluids.
One of the SWNT (single walled carbon nanotube) types, with an irregular horn-like shape.
See soft lithography.
Nanolithography is the art and science of etching, writing, or printing at the microscopic level, where the dimensions of characters are on the order of nanometers. This includes various methods of modifying semiconductor chips at the atomic level for the purpose of fabricating integrated circuits (ICs). Instruments used in nanolithography include the scanning tunnelling microscope (STM) and the atomic force microscope (AFM). Both allow surface viewing in fine detail without necessarily modifying it. Either the STM or the AFM can be used to etch, write, or print on a surface in single-atom dimensions.
The process of manipulating items at an atomic or molecular scale in order to produce precise structures.
One billionth of a metre. 10-9m, or a millionth of a millimetre.
Interaction of light and matter on the nanoscale.
Nanoscopic pores found in purpose-built filters, sensors, or diffraction gratings.
Nanoscale metal spheres that can absorb or scatter light at virtually any wavelength.
A nanowire wrapped into a helix.
Areas of technology where dimensions and tolerances in the range of 0.1nm to 100nm play a critical role.
A branch of tribology which studies friction phenomenon at the nanometer scale. The distinction between nanotribology and tribology is primarily due to the involvement of atomic forces in the determination of the final behaviour of the system.
A one-dimensional fullerene (a convex cage of atoms with only hexagonal and/or pentagonal faces) with a cylindrical shape.
One-dimensional structures, with unique electrical and optical properties, that are used as building blocks in nanoscale devices.
Nuclear Magnetic Resonance
The positively charged core of an atom, an object of -0.00001 atomic diameters containing >99.9% of the atomic mass. Nuclear positions define atomic positions.
LED made from carbon-based molecules, not semiconductors.
Any of various natural or synthetic compounds containing two or more amino acids linked by the carboxyl group of one amino acid to the amino group of another.
The technique used to produce the silicon chips that make up modern-day computers. The traditional process involves shining light through a mask onto a photosensitive polymer (photoresist) on a silicon surface, then subsequently removing the exposed areas.
Electronics using light (photons) instead of electrons to manage data.
The measurement of the polarisation of light; a polarimeter is the scientific instrument used to make these measurements. Polarimetry of thin films and surfaces is commonly known as ellipsometry.
A device used to plane-polarize light.
The set of proteins expressed by the genetic material of an organism under a given set of environmental conditions.
Refers to all the proteins expressed by a genome, and thus proteomics involves the identification of proteins in the body and the determination of their role in physiological and pathophysiological functions.
The chemical building blocks from which mammalian cells, organs, and tissues like muscle are made. Proteins also serve double-duty as hormones, enzymes and antibodies, which help fight off invading germs. Proteins are made of long chains of even smaller building blocks called amino acids. Amino acids determine the size, shape, and length of protein molecules. They also give protein molecules the odd ability to coil and uncoil like tiny, cellular snakes.
PVD Physical Vapour Deposition
Along with CVD, a group of surface treatments applied on tools and machine elements. In the area of machining and tooling PVD coatings are widely used to increase the life and productivity of production tools and therefore reducing manufacturing costs.
A computer that takes advantage of quantum mechanical properties such as superposition and entanglement resulting from nanoscale, molecular, atomic and subatomic components.
Quantum cryptographic systems take advantage of Heisenberg’s uncertainty principle, according to which measuring a quantum system in general disturbs it and yields incomplete information about its state before the measurement. Eavesdropping on a quantum communication channel therefore causes an unavoidable disturbance, alerting the legitimate users. This yields a cryptographic system for the distribution of a secret random cryptographic key between two parties initially sharing no secret information that is secure against an eavesdropper having at her disposal unlimited computing power. Once this secret key is established, it can be used together with classical cryptographic techniques such as the one-time-pad to allow the parties to communicate meaningful information in absolute secrecy.
A nano-scale crystalline structure that can transform the colour of light. The quantum dot is considered to have greater flexibility than other fluorescent materials, which makes it suited to use in building nano-scale computing applications where light is used to process information. They are made from a variety of different compounds, such as cadmium selenide.
A P-N-P junction in which the ‘N’ layer is ~10nm (where traditional physics leaves off and quantum effects take over) and an ‘electron trap’ is created.
Another form of quantum dot, but unlike the single-dimension ‘dot’, a quantum wire is confined only in two dimensions – that is it has ‘length’, and allows the electrons to propagate in a ‘particle-like’ fashion. Constructed typically on a semiconductor base.
The quantum-computing analogue to a bit. Qubits exhibit superposition. Thus, unlike normal bits, qubits can be both 1 and 0 at the same time.
Random Access Memory
Scanning Electron Microscopy (SEM)
Utilized in medical science and biology and in such diverse fields as materials development, metallic materials, ceramics, and semiconductors. SEM involves the manipulation of an electron beam that is scanned across the surface of specially prepared specimens to obtain a greatly enlarged, high-resolution image of the specimen’s exposed structure. Specimens are scanned with a very fine probe (‘tip’) and the strength of interaction between the tip and surface us monitored. The specimen can be observed whole for assessing external structure or freeze-fracture techniques can be used to image internal structures.
Scanning Force Microscope (SFM)
A SFM works by detecting the vertical position of a probe while horizontally scanning the probe or the sample relative to the other. The probe is in physical contact with the sample and its vertical position is detected by detecting the position of a reflected laser beam with a photo diode that consists of two or four segments.
Scanning Near Field Optical Microscopy (SNOM)
The operational principle behind near-field optical imaging involves illuminating a specimen through a sub-wavelength sized aperture whilst keeping the specimen within the near-field regime of the source. Broadly speaking, if the aperture-specimen separation is kept roughly less than half the diameter of the aperture, the source does not have the opportunity to diffract before it interacts with the sample and the resolution of the system is determined by the aperture diameter as oppose to the wavelength of light used. An image is built up by raster-scanning the aperture across the sample and recording the optical response of the specimen through a conventional far-field microscope objective. (As opposed to conventional optical microscopy or ‘far-field optical microscopy’).
Scanning Tunnelling Microscope (STM)
A device that obtains images of the atoms on the surfaces of materials – important for understanding the topographical and electrical properties of materials and the behaviour of microelectronic devices. The STM is not an optical microscope; instead it works by detecting electrical forces with a probe that tapers down to a point only a single atom across. The probe in the STM sweeps across the surface of which an image is to be obtained. The electron shells, or clouds, surrounding the atoms on the surface produce irregularities that are detected by the probe and mapped by a computer into an image. Because of the quantum mechanical effect called ‘tunnelling’ electrons can hop between the tip and the surface. The resolution of the image is in the order of 1nm or less.
Scanning Electron Microscope
A substance, usually a solid chemical element or compound, that can conduct electricity under some conditions but not others, making it a good medium for the control of electrical current. Its conductance varies depending on the current or voltage applied to a control electrode, or on the intensity of irradiation by infrared (IR), visible light, ultraviolet (UV), or X rays.
Scanning Force Microscope
Secondary Ion Mass Spectrometry
Solid Oxide Fuel Cell
A term for a collection of techniques (nanocontact printing, nanoimprinting, etc.) that are simple in concept and based around nanostructured forms, or moulds.
Electronics that exploits the spin of an electron in some way, rather than just its charge.
Refers to the use in materials processing or fabrication of the tendency of some materials to organize themselves into ordered arrays (e.g., colloidal suspensions). This provides a means to achieve structured materials “from the bottom up” as opposed to using manufacturing or fabrication methods such as lithography, which is limited by the measurement and instrumentation capabilities of the day. For example, organic polymers have been tagged with dye molecules to form arrays with lattice spacing in the visible optical wavelength range and that can be changed through chemical means. This provides a material that fluoresces and changes colour to indicate the presence of chemical species.
Reactive materials that combine sensors and actuators, and possibly computers, to enable a response to environmental conditions and changes to those conditions. Examples include uniforms or aircraft skins fabricated from radar-absorbing materials that incorporate avionic links and the ability to modify shape in response to airflow.
Scanning Near Field Optical Microscopy
Scanning Probe Microscope
Scanning Tunnelling Microscope
In nanotechnology the base material where applications are built up.
Single Walled Nanotubes
The maximum amount of tensile stress that can be applied to it before it ceases to be elastic. If too much force is applied the material will break or become plastic, i.e., once the force exertion is stopped the material will not go back to its initial shape.
A terabyte is a measure of computer storage capacity and is 2-40 or approximately a thousand billion bytes – a thousand gigabytes.
Tunnelling Electron Microscope
Thin films are atomically engineered layers of a wide variety of materials including metals, insulators and semiconductors. The major applications of thin films are in modification of the surface properties of solids. Individual films may be electrically conductive or non-conducting, hard or soft, thermally conducting or insulating, optically transparent, or opaque. A thin film coating can transform the electrical, mechanical and/or optical properties of a solid base material in a cost-effective way. Some common examples are scratch-resistant coatings for spectacles, anti-reflection coatings for lenses, transparent conducting coatings for flat-panel displays, and low-friction coatings for bearings. Hard coatings can significantly enhance the lifetime of cutting, drilling, and forming tools. Oxygen and moisture barrier films are in widespread use in the packaging of foodstuffs, contributing to the long shelf life of many convenience foods. Thin film coatings also have unique properties that may be exploited in the polarization, reflection, transmission and absorption of light. Complex coatings can be used to provide eye-protection from lasers without significant reduction in overall transmission and other high-performance films are in use for the multiplexing of telecommunication laser signals. Other inherent properties of thin films are used in microelectronics, magnetic recording and optical recording media.
The application of the principles and methods of engineering and the life sciences toward the fundamental understanding of structure/function relationships in normal and pathological mammalian tissues and the development of biological substitutes to restore, maintain, or improve functions.
Refers to making nanoscale structures by machining and etching techniques.
Unmanned Aerial Vehicle
Universal Dispensing Platform
The study of biological systems that exist primarily in a water environment. The functional nanometre-scale structures of interest here are genetic material, membranes, enzymes and other cellular components. The success of this nanotechnology is amply demonstrated by the existence of living organisms whose form, function, and evolution are governed by the interactions of nanometre-scale structures.
X-ray Photoelectron Spectroscopy
Any one of a family of hydrous aluminum silicate minerals, whose molecules enclose cations of sodium, potassium, calcium, strontium, or barium, or a corresponding synthetic compound, used chiefly as molecular filters and ion-exchange agents.
*The glossary of nanotechnology terms is provided by the UK Institute of Nanotechnology. For more information – http://www.nano.org.uk/about-us