1. Introduction. That synthesis might be undertaken by direct manipulation of atoms was suggested by Richard Feynman in 1959, although term nano-technology (1) was not coined until 1974, by Norio Taniguchi. In 1986, K. Eric Drexler published his book Engines of creation: coming era of nanotechnology, which contained notion of a assembler with capacity to build copies of itself and other items, by atomic level manipulation. The groundbreaking invention, in 1981, of scanning tunnelling microscope (STM) demonstrated that individual atoms could be visualised, and technology was further developed to physically move adsorbed atoms and molecules around on a surface (2). Notable examples (2) demonstrated for publicity purposes are sign-writing of IBM using 35 xenon atoms on a Ni(110) surface, and of 2000 using 47 CO molecules on a Cu(211) surface, by researchers in eponymous organisation, to auger in new millennium. Considerably larger molecules can also be moved using an STM tip, for example 1,4-diiodobenzene and biphenyl, which have been towed around on copper surfaces. The tunnelling electrons may also be used to initiate chemical reactions, products of which can be subsequently manipulated over surface, so providing proof of chemical change having occurred, e.g. conversion of iodobenzene to biphenyl. As a definition, nanotechnology (nanotech) can be described as manipulation of matter over an atomic, molecular, and supramolecular dimension. Molecular nanotechnology is intention of manipulating atoms and molecules, so to create macroscale products. The prefix nano is derived from Greek word meaning dwarf. The US National Nanotechnology Initiative (3) defines nanotechnology as, the manipulation of matter with at least one dimension in range 1-100 nm, where quantum mechanical effects become increasingly important as smaller end of range is accessed. It is critical that particular materials, and devices made from them, should possess properties that are different from bulk (micrometric or larger) materials, as a consequence of their small size, which may include enhanced mechanical strength, chemical reactivity, electrical conductivity, magnetism and optical effects (e.g. Figure 1). One nm is one billionth, or 10 (9), of a metre, which in relative size to a metre is about same as that of a marble to Earth (4). Placed in a different context, an average man's beard grows about 1 nm in time it takes him to lift razor to his face (4). The lower limit is set by size of atoms, which are fundamental building blocks of nanotechnology devices, while upper limit is of a more arbitrary quality but is of dimension at which particular phenomena of quantum realm begin to appear, which are essential to nano-device. A device that is merely a miniaturised form of an equivalent macroscopic version does not ascribe to nanotechnology, lacking these particular phenomena, but is classified under heading microtechnology'. In regard to fabrication of nanodevices, we find bottom-up approach, where materials and devices are constructed from molecular components which self-assemble via molecular recognition, while in top-down approach, nano-objects are built from larger entities, not involving control at an atomic level (6). [FIGURE 1 OMITTED] The plural forms nanotechnologies and nanoscale technologies thus refer to many and various aspects, devices and their applications that have in common this scale of quantum realm. Indeed, there are multifarious potential applications of materials, including industrial and military uses, as attested by investment of $3.7 billion, by US National Nanotechnology Initiative, $1.2 billion by European Union and $ 750 million in Japan (1). It may be that nanotechnology can provide advances in medicine, electronics, biomaterials, energy production and, as is subject of this article, in agriculture and more broadly in food industry. …
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Apr 6, 2015
A González-Tudela + 4
Open Access
