It is a measure of the potential and newness of this technology that the public knows of it mainly through science fiction and films
In Michael Crichton's 2002 sci-fi thriller, Prey, Jack Forman, a Silicon Valley computer programmer with serious job and marital problems, has been thrust into a military experiment in nanotechnology that has gone haywire. Xymos, a defense contractor on the Nevada desert, has developed molecular-scale cameras that can be injected into the bloodstream to monitor diseases -- think Fantastic Voyage without Raquel Welch. The medical application, however, is only a cover for what they are actually making: clouds or "swarms" of tiny nanoscale cameras designed to spy on the enemy.
Jack's wife works for the same top-secret firm, and things quickly get terribly personal for him. But his real problem is trying to bring a runaway technology back under control. It seems that Xymos has magically achieved the fantasy goal of nanotechnology: not only creating molecules by manipulating atoms, but programming atoms to come together on their own, a process known as "self-assembly." The problem is that, once they can self-replicate, these nanoparticles start to behave functionally like living creatures; they don't need humans anymore and anything can happen. Armed with a smidgeon of artificial intelligence, the swarms, so called for their mimicry of the social behavior of bees, are able to learn and evolve with astonishing speed. They go after Jack and anyone who threatens their freedom. The whole world is at peril. Jack wins, but just barely.
Prey ends with some unbelievable death-defying scenes and, for the sake of a good yarn, takes this still-infant technology to implausible extremes. But like the best science fiction writers, the late Crichton could be remarkably prescient about technological breakthroughs, if not their human and social impacts, which are always up for grabs. For example, as I write this, a DARPA-funded company is showing off a tiny flying gadget, its so-called Nano Hummingbird, complete with spy video camera -- not strictly nano but on the road to it.
A counterbalance to Crichton's dystopian vision is the one given by theoretical physicist Michio Kaku in his new book, Physics of the Future. Sensitive to the critiques of nanotechnology, he asks if it will "unleash the fire of enlightenment and knowledge or the winds of chaos?" Kaku looks on the bright side and opts emphatically for the former view; it can and will be controlled, he insists. He then takes us through near, middle and far future scenarios, based on interviews with working scientists. His examples include super gyroscopes, designer molecules that hunt down cancer cells, DNA "on a chip" that monitors our health, remote-controlled "nanocars" that patrol our bloodstream for cancers (Fantastic Voyage, again), carbon nanotubes stronger than steel, non-silicon substrates for faster chips and computers, shape-shifting and self-healing structures (think here Terminator II) and the nanotechnologist's holy grail, the "replicator" that perhaps by 2100 will manufacture everything at the atomic level practically from nothing, including body organs. The world's major problem will then be the sociopolitical one of learning how to cope with this limitless supply of goods.