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Why The Old Rules Don't Apply


How does nanotech work? For starters, it's tiny. For lots of jobs today, that's a prerequisite. The semiconductor industry needs ever-smaller tools and components to build coming generations of chips. Nothing bigger than nano-scale bits will fit. Similarly, some of the latest fuel cells carry nano-scale meshes on their filters. These help to sift electrons from hydrogen ions -- a crucial step in creating electricity. For exacting work like that, nano -- from the Greek for dwarf -- is a perfect fit.

Nanotech derives much of its power from transformations that occur when matter is reduced to the molecular dimension. For example, breaking down a chunk of a material into nanoparticles vastly increases its surface area, often by a factor of millions. This makes it dramatically more reactive -- quicker to ignite or melt and absorbing more faster. Think of a spoonful of confectioner's sugar dissolving instantly in a cup of coffee, while a sugar cube in another cup has barely begun to lose its sharp corners.

Why does this matter? Drugmakers are betting that nano's greater absorption rate will lead to far more efficient dosages of drugs, many delivered as nano specks. And by making the particles chemically reactive, scientists are building exquisitely sensitive sensors that can detect individual molecules.

Thanks to all that surface area, nanoparticles often appear hypersensitive. Take gold. Although inert when wrapped around a finger or filling a tooth, at its tiniest size it becomes a potent catalyst -- one that could be used to purge carbon monoxide from the atmosphere. And aluminum at the nano scale "can catalyze rocket fuel," says Steve Jurvetson of Silicon Valley venture-capital firm Draper Fisher Jurvetson, which has invested some $95 million in 11 nano startups. "It literally explodes."

Lots of other changes occur when matter sheds its heft. Some nano materials, when reduced to a size smaller than a wavelength of light, become invisible. This opens the possibility of having materials we know as opaque, such as silicon, transmit light. Others become fabulously strong. Carbon nanotubes, for example, share a similar atomic structure with their cousin, the diamond. This makes them sturdy, yet their willowy form leaves them as flexible as a noodle -- a combination of strength and suppleness that's tough to find in the larger universe.

Lots of the nano world remains a mystery. In its miniature form, matter pays little heed to the familiar world of Newtonian physics. The laws of gravity, optics, and acceleration represent averages, not the quirky behavior of each single nanoparticle. For those principles, researchers must venture into quantum physics. Those who come to grips with this realm and can harness its power stand to become the titans of the nano age.

By Stephen Baker and Adam Aston in New York


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