SPECIAL ISSUE S E P T E M BE R 20 01 $4. 95 W W W. S CI A M. COM Medical Nanoprobes Buckytube Electronics Living Machinery Atom-Moving Tools New Laws of Physics Nano Science Fiction NANOTECH The Science of the Small Gets Down to Business ALSO Eric Drexler on Nanorobots and Richard Smalley on Why They Won’t Work Copyright 2001 Scientific American, Inc. contents september 2001 SCIENTIFIC AMERICAN Volume 285 Number 3 SPECIAL NANOTECHNOLOGY ISSUE features Magnified tip of an atomic force microscope OVERVIEW 32 Little Big Science BY GARY STIX Nanotechnology is all the rage. Will it meet its ambitious goals? And what is it, anyway? NANOFABRICATION NANOVISIONS 74 Machine-Phase Nanotechnology BY K. ERIC DREXLER 38 The Art of Building Small BY GEORGE M. WHITESIDES AND J. CHRISTOPHER LOVE The search is on for cheap, efficient ways to make structures only a few billionths of a meter across. The leading visionary in the field forecasts how nanorobots will transform society. NANOFALLACIES 76 Of Chemistry, Love and Nanobots BY RICHARD E. SMALLEY NANOPHYSICS A Nobel Prize winner explains why self-replicating nanomachines won’t work. 48 Plenty of Room, Indeed BY MICHAEL ROUKES There is plenty of room for practical innovation at the nanoscale— once the physical rules are known. NANOINSPIRATIONS 78 The Once and Future Nanomachine BY GEORGE M. WHITESIDES NANOELECTRONICS Lessons from nature on building small. 58 The Incredible Shrinking Circuit BY CHARLES M. LIEBER Researchers have built nanoresistors and nanowires. Now they have to find a way to put them together. NANOROBOTICS 84 Nanobot Construction Crews BY STEVEN ASHLEY One company’s quest to develop nanorobots. NANOFICTION NANOMEDICINE 66 Less Is More in Medicine 86 Shamans of Small BY A. PAUL ALIVISATOS BY GRAHAM P. COLLINS Nanotechnology’s first applications may include biomedical research and disease diagnosis. Nanotechnology has become a favorite topic of science-fiction writers. www.sciam.com SCIENTIFIC AMERICAN Copyright 2001 Scientific American, Inc. 5 SCIENTIFIC AMERICAN Volume 285 Number 3 departments 8 SA Perspectives The National Nanotechnology Initiative brings a welcome boost to the physical sciences and engineering. 10 10 12 16 18 18 How to Contact SA On the Web Letters 50, 100 & 150 Years Ago News Scan ■ ■ ■ ■ ■ ■ ■ ■ 26 30 Profile: Elizabeth Gould This neurobiologist looks at how memory and healing in the brain may rely on the growth of new neurons. Solved: the solar neutrino problem. Drawbacks of the cancer-fighting drug Gleevec. Retinal displays for pilots. How snowball Earth got rolling. No more anonymous Web surfing? Hunting jaguars with darts. By the Numbers: Reliability of crime statistics. Data Points: Believers in the paranormal. 66 92 Working Knowledge Fleas flee from new “spot” treatments used on pets. 94 Voyages Geological tours expose the innermost secrets of New York City and beyond. 98 Reviews Science, Money, and Politics: Political Triumph and Ethical Erosion depicts American “Big Science” as a bloated, whiny, self-important bureaucracy. columns 29 Skeptic BY MICHAEL SHERMER The new religion of cryonics offers to raise its faithful dead. 102 Puzzling Adventures BY DENNIS E. SHASHA Square dancing without collisions. 103 Anti Gravity BY STEVE MIRSKY Never take off your shoes near a Komodo dragon. 104 Endpoints ABOUT