Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications. Encompassing nanoscale science, engineering and technology, nanotechnology involves imaging, measuring, modeling, and manipulating matter at this length scale.
At the nanoscale, the physical, chemical, and biological properties of materials differ in fundamental and valuable ways from the properties of individual atoms and molecules or bulk matter. Nanotechnology R&D is directed toward understanding and creating improved materials, devices, and systems that exploit these new properties.
In 1959, the year the first artificial satellite climbed into orbit, the brilliant, Bohemian US physicist Richard Feynman gave a talk at an American Physical Society meeting at Caltech called "There's Plenty of Room at the Bottom." It was entertaining and mind-stretching, as were all Feynman's offerings. More importantly, it marked the intellectual beginnings of the field that became known as nanotechnology – an endeavor that promises a cornucopia of scientific miracles or, if things go badly wrong, a quick and messy end to the Earth and everything on it.
The prefix "nano" comes from the Greek nanos for "dwarf." In metric units it means a billionth; so a nanometer is a billionth of a meter. It's a handy unit for measuring the size of atoms and molecules. For instance, a hydrogen atom – the smallest of all atoms – is about a tenth of a nanometer (0.1 nm) across, while a molecule of hemoglobin (the substance that carries oxygen in our blood) is about 5 nm across. Nanotechnology, a term coined by Tokyo Science University professor Norio Taniguchi in 1974, got its name because it has to do with manipulating matter at the atomic and molecular level, typically in the 1 to 100 nm range.
"Consider," said Feynman in his talk, "the final question as to whether, ultimately – in the great future – we can arrange the atoms the way we want; the very atoms, all the way down!" At the time his suggestion must have seemed more like science fiction than anything we could ever actually achieve, but in the 1980s American engineer K. Eric Drexler began promoting the ideas and potential of nanotechnology with evangelical zeal in speeches and a best-selling book, Engines of Creation: The Coming Era of Nanotechnology.
Drexler was inspired early in his career by grand innovative schemes such as space colonies and other ambitious solutions to impending human crises – over-population, resource depletion, and the like. Nanotechnology he saw as a panacea to many of the world's problems. What he called "universal assemblers" (microscopic machines that build atom by atom) could be used, he suggested, to make everything from miniature medical subs that would patrol a patient's blood vessels, delivering drugs or clearing blocked arteries, to molecular-sized environmental scrubbers that took pollutants out of the air.
But even Drexler, extreme advocate of what he saw as one of the next great revolutions, was alive to the perils of meddling at the molecular level. He envisaged the possibility of self-replicating nanomachines – devices that could make perfect copies of themselves – being released into the environment to tackle problems like oil spills or air pollution. If these went awry and began breaking down all kinds of other molecules, they could quickly and disastrously reduce the whole Earth to a ball of uniform nano-sludge he called "gray goo."
Applications and products
While nanotechnology is in the "pre-competitive" stage (meaning its applied use is limited), nanoparticles are being used in a number of industries. Nanoscale materials are used in electronic, magnetic and optoelectronic, biomedical, pharmaceutical, cosmetic, energy, catalytic and materials applications. Areas producing the greatest revenue for nanoparticles reportedly are chemical-mechanical polishing, magnetic recording tapes, sunscreens, automotive catalyst supports, biolabeling, electroconductive coatings and optical fibers.
Today most computer hard drives contain giant magnetoresistance (GMR) heads that, through nano-thin layers of magnetic materials, allow for an order of magnitude increase in storage capacity. Other electronic applications include non-volatile magnetic memory, automotive sensors, landmine detectors and solid-state compasses.
Nanomaterials, which can be purchased in dry powder form or in liquid dispersions, often are combined with other materials today to improve product functionality.
Another important area of nanotechnology R&D is medicine. Medical researchers work at the micro- and nano-scales to develop new drug delivery methods, therapeutics and pharmaceuticals. For a bit of perspective, the diameter of DNA, our genetic material, is in the 2.5 nm range, while red blood cells are approximately 2.5 micrometers.