Glossary of terms used on NANO Magazine

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Catalyst

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

Catenane

The latest molecular switches are created using unique molecules, called catenanes, which consist of two tiny mechanically interlocked rings, each ring composed of atoms linked in a circle. Catenanes are an improvement over rotaxane molecules. Rotaxanes are in a solution state and are much more incoherent.

Cations

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).

Cell

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.

Chromatography

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.

Composites

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).

Cyclodextrin

Natural polysaccharide deriving from chitin, chitosan is cationic in acidic media

Dendrimer

A dendrimer is an artificially manufactured or synthesized large molecule comprised of many smaller ones linked together - built up from branched units called monomers. Technically, dendrimers are a unique class of a polymer, about the size of an average protein, with a compact, tree-like molecular structure, which provides a high degree of surface functionality and versatility. The shape of dendrimers give them vast amounts of surface area, making them useful building blocks and carrier molecules at the nanoscale and they come in a variety of forms, with different physical (including optical, electrical and chemical) properties. For example, dendrimers can act as biologically active carrier molecules in drug delivery to which can be attached therapeutic agents and as scavengers of metal ions, offering the potential for environmental clean-up operations because their size allows them to be filtered out with ultra-filtration techniques.

Diode

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.

DNA

DeoxyriboNucleic Acid. DNA is a code used within cells to form proteins.

DRAM

Dynamic random access memory.

EAPs

ElectroActive Polymers

Elastomeric stamp or mould

Key element in soft lithography usually made from polydimethylsiloxane (PDMS), having patterned relief structures on its surface.