Nanotechnology is a word that seems to mean all things to all men. All it is, however, is technology on a “nano” scale: ie, employing devices with dimensions measured in nanometres (billionths of a metre). Since that is the scale of large molecules, many cynics regard it as merely a fancy name for chemistry.
The inventor of the term, Eric Drexler, then an engineer at the Massachusetts Institute of Technology, had greater ambitions. In “Engines of Creation”, a book published in 1986, he argued that it would be possible one day to construct self-replicating “nanomachines” that could assemble atoms into molecules, thus building new objects from the inside out.
On the face of things, that sounds ambitious. But there are already things that work more or less this way: living cells. If Dr Drexler's vision is ever to come to pass, it may not take the form of molecule-sized cogs and fly-wheels, as he originally thought, but of artefacts that interact with the natural nanotechnology of biology.
“Nanobiotechnology” or “nanomedicine”, as this field is variously called, is a natural marriage. A cell is a warehouse of nanoscale machines. It is held in shape by a scaffold of microtubules, whose components have diameters measured in nanometres. Its proteins are manufactured on nanoscale assembly lines called ribosomes and packaged into shape by another nanoscale device known as the Golgi apparatus. Those proteins are often themselves nanoscale machines called enzymes—machines designed to rip molecules apart or join them together, according to a cell's needs. Artificial devices that interacted with these machines could analyse a cell's contents, deliver drugs to it, kill it if it became a nuisance—or even harness it to work as a miniature factory.......................
