NANOTECHNOLOGY might be a multibillion-dollar industry in the making, but you'd never know it from a visit to Mark Hildebrand's lab. His workers churn out elaborate microscopic structures for a salary that adds new meaning to the term "minimum wage". "To get billions of them working costs about a dollar," says Hildebrand.

The workers in his lab at the University of California in San Diego are diatoms - microscopic, single-celled algae that are well known for their beautiful and elaborate glass shells. Hildebrand isn't interested in their aesthetic merits, though. He and other like-minded researchers think all sorts of applications could be found for diatoms in nanotechnology, from acting as tiny moulds to fashioning lenses for optical computers and growing gears for micro-robots.

To a nanotechnologist, diatoms seem almost heaven-sent. Not only do they turn out precision-made, three-dimensional structures quickly, cheaply and in enormous quantities, they do so at room ...