By Michael Grebb, Thu Mar 27 13:00:00 GMT 2003

They use distributed computing and communicate wirelessly, and learn as they go.

A swarm of nanobots has escaped the lab. They use distributed computing and communicate wirelessly. They learn as they go. They are able to create widespread mayhem in the environment. And they are unstoppable.

That's the basic premise of Michael Crichton's new book, Prey, which paints a nightmarish scenario of what could happen if scientists tinkering with nanotechnology aren't careful. Like many of his books, Crichton bases the story on science but takes shortcuts to get there (the microscopic machines are made possible by genetic engineering that gets around some of the hurdles of constructing such tiny bots in massive quantities). And like many of Crichton's other books, it has spurred more discussion of the possibilities of a future in which nanobots could be as common as the air we breathe. Of course, the experts have a word of advice for those of us easily excited by science fiction: Don't hold your breath.

"It's not that nanobots aren't going to be possible," says Kevin Ausman, executive director of Rice University's Center for Biological and Environmental Nanotechnology. "But if they're possible, it will be so far in the future that we shouldn't worry about it. And when I say that, I mean with our limited time and resources." Indeed, many problems exist in creating nanobots that are invisible to the human eye and can still move around freely. And once researchers surmount that hurdle, they must figure out a way to make nanobots self-replicating. Otherwise, a factory would have to churn out millions of them for the technology to be useful - a feat that is quite simply cost and time prohibitive.

And then assuming they meet those challenges, devising a networked model in which a cloud of nanobots could work together to clean the air or swim through bloodstreams to kill cancer cells... well, that's an even bigger problem. It's hard enough to make wireless transmitters and receivers small enough to satisfy the public's thirst for tiny handsets, much less master the chemical process that would enable wireless communications at the microscopic level. And you thought battery power was a problem with cell phones? Try powering millions of microscopic gnats.

Nanotechnology: Think Small

Nanotechnology is essentially the art of building structures by manipulating individual atoms. Ausman and others predict it will be at least 20 years before self-replicating nanobots that could exploit a distributed wireless computing infrastructure are even remotely possible. And even that's assuming scientists combine biochemistry with nanotechnology to create machines that model themselves on living organisms. "If we can ever get the chemistry and control good enough to make a nanobot," offers Ausman, "they would be modeled on the self-replicating cells we already know, which is life."

Some nanobot proponents think that modeling nanobots on biological systems isn't necessarily required to create wireless functionality and self-replication. But Ausman says such an approach could be up to 50 years in the future. "And once you're at 50 years, it's not really worth talking about," he says. Chris Peterson, a researcher at the Foresight Institute, agrees that true wireless nanobots could be decades away but insists that the technology would come much sooner if governments created a massive research effort similar to the Apollo project that launched the U.S. space program. "We don't yet have a consensus that it's time to do this project," she says. "We have to have a decision of someone to spend a lot of money. It's a big engineering project."

The hurdles now facing researchers are huge. Before they can even think about the wireless-distributed computing aspect envisioned by science fiction (and vital to create "intelligent" nanobots), they must first master manufacturing at the molecular level. "The big challenge is the thermal noise," says Peterson. Thermal noise consists of the vibrations all around us, which increase as the temperature rises. For large structures, they are practically undetectable. But for microscopic machines, they can ruin the precise manufacturing process. "It's a very serious issue," she says. "We've got to find a way to make the vibrations part of the solution. This is going to be very hard."

In the short term, it may be more plausible to embed wireless communications in extremely small but not technically nano-sized devices. Using micro-electro-mechanical systems (MEMS) technology, devices "the size of a date on a dime" could be used to detect substances in the air or perform other tasks, says Edward Moran, who leads the nanotechnology industry practice for Deloitte & Touche. They may be immobile initially, but they will be wireless. "I think the easiest part of the whole puzzle is the wireless part," he says. "It's very soon that we'll have these tiny, tiny devices networking around us. This is real. This is not science fiction."

Of course, the mobile, microscopic nanobots so dear to science-fiction dreamers remain decades away. And considering the scenarios dreamed up by people like Michael Crichton, maybe that's not such a bad thing.

Michael Grebb has also written for Wireless Week, Business 2.0, and Wired News. From Washington DC, he covers the impact of mobile technology on modern society.