Reality Check

The Future of Nanotechnology

Nanotechnology is a "bottom-up" approach to engineering in which individual molecules are positioned to build tiny machines. (The prefix nano refers to the scale of a nanometer, one-billionth of a meter.) You've probably already heard the nanotech hype – predictions of molecular-sized robots programmed to eat up pollution, or of tiny machines sailing through our bloodstreams.

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But the reality is far more prosaic. (See "Nanotech: Engines of Hyperbole?" Wired 1.6, page 84.) Only the most tentative steps toward useful engineering tools have been made, and most studies are limited to computer simulation. With that in mind, Wired asked several nanotech experts to estimate when we will reap the rewards of their research.



Molecular Assembler Nanocomputer Cell Repair Commercial Product Nanotech Law Robert R. Birge 2005 2040 2030 2002 1998 Donald W. Brenner 2025 2040 2035 2000 2036 K. Eric Drexler 2015 2017 2018 2015 2015 J. Storrs Hall 2010 2010 2050 2005 1995 Richard E. Smalley 2000 2100 2010 2000 2000 Bottom Line 2011 2041 2029 2004 2009 David Pescovitz

Molecular Assembler: To easily build nanomachines, we need a device that can rotate and precisely position individual molecules. Several of those polled cite progress with scanning tunneling microscopes and atomic force microscopes, both of which are capable of pushing around individual atoms or etching submicrometer-wide lines. But engineering a device that grips molecules so they can be rotated, Birge points out, is a far more difficult feat. The forces that hold together the atoms composing the gripper have to be stronger than the atoms or molecules moved. While Drexler believes that "a crude and somewhat useful assembler" using atomic force microscopes may be just a few years away, he says "major results will require nanoscale assemblers" (machines that are themselves molecular-sized). Nanocomputer: Most of our experts believe computers the size of bacteria will not be developed any time soon. Too bad, because, theoretically, these nanocomputers could process information billions of times faster than any machine we have today. In fact, Drexler believes that nanocomputers could finally provide the horsepower needed for artificial intelligence. He also predicts that we may be able to build nanocomputers without nanoscale assemblers. However, Brenner says that at the nanoscale, "electrons begin to show very odd behavior, governed by quantum mechanics." He believes that nanocomputers "will require serious rethinking of traditional computer design." Birge favors the concept of hybrid computers that combine semiconductors with light-sensitive switches made from certain proteins. Cell Repair: Building a molecular machine that repairs damaged cells "is an enormously complex engineering task," says Drexler, but one that might be possible with the help of artificial intelligence derived from nanotechnology. However, Brenner says that "repairing a cell as one would repair a car – using mechanical forces – is definitely not the way to go." A better approach, he believes, would combine more natural chemical methods with "a specially designed vehicle that would selectively deliver a chemical reagent to a cell." Similarly, the cell-repair machine that Smalley envisions is not built atom by atom but is protein-based and likely to be "less than 10 percent of original, de novo human design." But Hall points out that "gene modification by viruses is done now and will stay ahead of nano in sophistication." Commercial Product: Smalley thinks the first commercial product created with molecular nanotechnology is likely to be a chemically synthesized bio-sensor on the tip of a needle. The sensor would recognize biological agents in the bloodstream or measure blood-sugar levels and send the information out of the body for analysis. Drexler, however, predicts that "a good candidate for the first product to make a big splash in a traditional high-technology field is molecular-based computer memory." Such a system could offer terabytes of storage. Hall believes that early nanotech memory devices might use a modified scanning tunneling microscope-type probe to read and write on a storage medium of a monolayer of molecules created by ordinary chemistry. In fact, a Stanford physicist has already used an atomic force microscope to build transistors that are on the verge of the nanoscale. Nanotech Law: Several of our experts predict that within five years, the government will step in to create laws or regulations concerning nanotechnology. The only specific law that Brenner forsees is "one regulating molecular machines that attack rather than repair human cells, although these may already be covered by existing laws pertaining to chemical, biological, and conventional weapons." Drexler agrees that the potential use of nanotechnology for the creation of powerful weapons systems should be considered. But adds that if "the concern is excessively vivid and distracts from the positive uses of the technology," it could have the wrong impact on policy. "Rather than predicting what readers of this article will do," Drexler says, "I'd rather ask them to think long and hard about what policies would be wise and worth supporting."

Reality Checkers

Robert R. Birge

PhD, distinguished professor of chemistry, and director of the W. M. Keck Center for Molecular Electronics, Syracuse University

Donald W. Brenner

PhD, associate professor, department of materials science and engineering, North Carolina State University

K. Eric Drexler

PhD, chairman, Foresight Institute; author, Engines of Creation: The Coming Era of Nanotechnology.

J. Storrs Hall

PhD, computer scientist, Rutgers University; moderator, sci.nanotechnology Usenet newsgroup

Richard E. Smalley

PhD, professor of chemistry and physics, Rice University; chief instigator of Rice's imminent Center for Nanoscale Science and Technology