Source: SCIENCE NANO-COPTER twirls its tiny nickel propellers when fueled with ATP, the molecule that powers cells. The biomotor is made of ATPase (top left), which is attached to the nickel propellers and mounted on a nickel post (bottom left). Put in a solution of ATP and other chemicals, the propellers spin at a rate of eight revolutions per second.

"It is a staggeringly small world that is below," Richard Feynman said in his famous 1959 speech about nanotechnology, There¿s Plenty of Room at the Bottom. "In the year 2000, when they look back at this age, they will wonder why it was not until the year 1960 that anybody began seriously to move in this direction." In fact, what may now inspire greater wonder is just how far nanotechnologists have come in 40 years. In the past week alone, a flurry of papers describing advances on many fronts have come forth, both in the November 23 issue of Nature and in the November 24 issue of Science, which contains a special section on nanotechnology.

The reports come fast after several calls for concern over the pace at which nanotechnology is progressing. In the April issue of Wired, Bill Joy, co-founder of Sun Microsystems, warned that research in nanotechnology should be stopped before it becomes the "gray goo" K. Eric Drexler described in his 1986 book Engines of Creation. The goo, as Drexler envisioned it, would consist of legions of miniature assemblers that replicated themselves ad infinitum, wiping out anything living or not in their path. In June, nanotechnologists from the Foresight Institute--a think tank where Drexler is chair--followed suit, issuing their own prophylactic guidelines to stop goo.

But other scientists--many of whom air their views in news items that accompany Science's special section--dismiss the grim predictions. And if nanotechnology doesn't devour humanity, it does appear to hold tremendous promise to help it. In the cover story from Nature, Galen Stucky and his colleagues at the University of California, Santa Barbara describe glassy materials with nanoscale pores, cages and channels that might be used, among others things, "to sense biotoxins and for the removal of toxic heavy metals from the environment." In that same issue, Virginia Tech chemist Harry Dorn describes a new breed of metal-containing fullerenes, which can be used as nanoscale building blocks.

In Science, Caltech physicists Stephen Quake and Axel Scherer review how soft materials--which are perhaps better suited than stiff silicon for nanoscale devices handling biological samples--are coming into their own. Cornell researcher Harold Craighead explains how new nanoelectromechanical systems (NEMS)--the smaller cousins of microelectromechanical systems (MEMS)--are paving the way for "a revolution in applications such as sensors, medical diagnostics, displays and data storage." And other papers lay out work being done to develop so-called nanonurses, which travel the body to find and fix problems within cells, and labs-on-chips, designed to carry out genetic analyses and other diagnostic tasks. The list goes on. Perhaps three of the more exciting results--twirling biomolecular nano-coptors, microrobots based on bending plastic actuators and dancing tin nanomotors--are described in greater depth below. --Kristin Leutwyler

Twirling Motors

Researchers from the Cornell Nanobiotechnology Center have devised a way to power virus-sized motors using the very same molecule that provides energy within cells, adenosine triphosphate (ATP). In Science, Carlo Montemagno and his colleagues explain how they built and tested the first such biomolecular motors, marrying inorganic nickel propellers to ATPase enzyme (see illustration). "With this demonstration, we believe we are defining a whole new technology," Montemagno says. "We have shown that hybrid nanodevices can be assembled, maintained and repaired using the physiology of life."

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