rise of nanotech

Download Rise of Nanotech

Post on 12-Mar-2015

127 views

Category:

Documents

2 download

Embed Size (px)

TRANSCRIPT

Articial Molecules Deliver Drugsp. 72

DNA Building Blocksp. 30

Nanotech in Sci-Fip. 80

REPORTSspecial edition on nanotechnology

w w w. Sc i A m.com

NANOTECHHow control of molecules is changing the worldInvisibility Cloak?Bending Light with Plasmonics

THE RISE OF

Computing with DNATiny Machines Speak to Cells

Carbon NanonetsElectronics Gets a Boost

Weird PhysicsSmall Size, Big DifferencesCarbon nanotube

COPYRIGHT 2007 SCIENTIFIC AMERICAN, INC.

Page Intentionally Blank

SCIENTIFIC AMERICAN Digital

REPORTSScienti c American Reports is published by the staff of Scientic American, with project management by:E D I T O R I N C H I E F : John Rennie E X E C U T I V E E D I T O R : Mariette DiChristina I S S U E E D I T O R : Dawn Stover A R T D I R E C T O R : Patricia Nemoto P H O T O G R A P H Y E D I T O R S : Emily Harrison,

letter from the editor

Small Worldi f you h av e heard about nanotechnology at all, you may be aware of its science-ction-sounding hype. Proponents picture a future in which tiny bots would magically repair tissue to prolong our life span. On the dark side is the disturbing vision of gray goo, where self-replicating nanodevices destroy the planet. The reality of the burgeoning field of nanotech, however, is hardly less startling in its transformative potential. Some have proclaimed it the next industrial revolution. Nanotechnology broadly applies to control of materials and comCarbon nanotube ponents only a few billionths of a meter in size. Already manufacturers sell several hundred products that use nanotech, mainly skin lotions. Next up are advances in biotechnology and electronics and a merging of the two. Consider, for instance, molecular building blocks called bis-amino acids, which chemists string together into proteinlike structures, as described by Christian E. Schafmeister in his article, Molecular Lego, starting on page 22. Applications include medicines, enzymes for catalyzing reactions, sensors, nanoscale valves and computer storage devices. Other researchers are using natural molecular machines to process information: they receive input from other biological molecules and output a tangible result, such as a signal or a therapeutic drug. For more, turn to Bringing DNA Computers to Life, by Ehud Shapiro and Yaakov Benenson, on page 40. Nanoscience advances are pushing traditional electronics in new directions as well. In Carbon Nanonets Spark New Electronics (page 48), George Gruner describes applications that encompass sensors, solar cells, electronic paper and bendable touch screens. Imagine a morning paper with headlines that change as news breaks. Or how about an invisibility cloak? In The Promise of Plasmonics (page 56), Harry A. Atwater explains how optical signals squeeze through minuscule wires, producing so-called plasmons. Plasmonic circuits could help to move lots of data and improve the resolution of microscopes, the efciency of light-emitting diodes, and the sensitivity of detectors. Such materials could alter the electromagnetic eld around an object to such an extent that it would become invisible. The nanoregime offers enormous promise indeed. Mariette DiChristina Executive Editor Scientic American editors@SciAm.com

Smitha AlampurP R O D U C T I O N E D I T O R : Richard Hunt C O P Y D I R E C T O R : Maria-Christina Keller C O P Y C H I E F : Daniel C. Schlenoff A S S I S T A N T C O P Y C H I E F : John Matson C O P Y A N D R E S E A R C H : Rachel Dvoskin,

Aaron Shattuck, Kenneth Silber, Kevin Singer, Michelle WrightE D I T O R I A L A D M I N I S T R A T O R : Jacob Lasky S E N I O R S E C R E T A R Y: Maya Harty A S SOCI ATE PUBLISHER, PRODUC TION:

William ShermanM A N U F A C T U R I N G M A N A G E R : Janet Cermak ADVERTISING PRODUC TION MANAGER:

Carl CherebinPREPRES S AND QUALIT Y MANAGER:

Silvia De SantisP R O D U C T I O N M A N A G E R : Christina Hippeli CUS TOM PUBLISHING MANAGER:

Madelyn Keyes-MilchA S SOCI ATE PUBLISHER, CIRCUL ATION:

Simon AroninC I R C U L A T I O N D I R E C T O R : Christian Dorbandt R E N E W A L S M A N A G E R : Karen Singer FULFILLMENT AND DIS TRIBUTION MANAGER:

Rosa DavisVICE PRESIDENT AND PUBLISHER:

Bruce BrandfonS A L E S D E V E L O P M E N T M A N A G E R : David Tirpack S A L E S R E P R E S E N T A T I V E S : Jeffrey Crennan,

Stephen Dudley, Stan SchmidtA S SOCI ATE PUBLISHER, S TR ATEGIC PL A NNING:

Laura SalantP R O M O T I O N M A N A G E R : Diane Schube R E S E A R C H M A N A G E R : Aida Dadurian P R O M O T I O N D E S I G N M A N A G E R : Nancy Mongelli G E N E R A L M A N A G E R : Michael Florek B U S I N E S S M A N A G E R : Marie Maher MANAGER, ADVERTISING ACCOUNTING AND C O O R D I N A T I O N : Constance Holmes DIREC TOR, SPECIAL PROJEC TS:A L F RED PA S IEK A SPL /Photo Researchers, Inc.

Barth David SchwartzM A N A G I N G D I R E C T O R A N D V I C E P R E S I D E N T, O N L I N E :

Mina C. LuxDIREC TOR, WEB TECHNOLOGIES, ONLINE:

Vincent MaS A L E S R E P R E S E N T A T I V E , O N L I N E : Gary Bronson DIREC TOR, ANCILL ARY PRODUC TS:

Diane McGarveyP E R M I S S I O N S M A N A G E R : Linda Hertz C H A I R M A N : Brian Napack C H A I R M A N E M E R I T U S : John J. Hanley VICE PRESIDENT AND MANAGING DIREC TOR, I N T E R N A T I O N A L : Dean Sanderson V I C E P R E S I D E N T: Frances Newburg

w w w. S c i A m . c o m

COPYRIGHT 2007 SCIENTIFIC AMERICAN, INC.

SCIENTIFIC A MERIC A N REPORT S

1

Contents12

401 Letter from the Editor BUILDING BLOCKS 4 Plenty of Room Indeedby Michael Roukes There is plenty of room for practical innovation at the nanoscale. But rst, scientists have to understand the unique physics that governs matter there.

LIVING MACHINES 30 Nanotechnology and the Double Helixby Nadrian C. Seeman DNA is more than just the secret of life it is also a versatile component for making nanoscopic structures and devices.

40 Bringing DNA Computers to Lifeby Ehud Shapiro and Yaakov Benenson Tapping the computing power of biological molecules gives rise to tiny machines that can speak directly to living cells.

12 The Art of Building Smallby George M. Whitesides and J. Christopher Love Researchers are discovering cheap, efficient ways to make structures only a few billionths of a meter in size.

22 Molecular Legoby Christian E. Schafmeister A modest collection of small molecular building blocks enables the design and manufacture of nanometer-scale structures programmed to have virtually any shape desired.Cover illustration by Alfred Pasieka, SPL/Photo Researchers, Inc. The articles in this special edition are updated from previous issues of Scientific American.

2

SCIENTIFIC A MERIC A N REPORT S

S E P T E M B E R 2 0 07

COPYRIGHT 2007 SCIENTIFIC AMERICAN, INC.

Volume 17, Number 3, 2007

REPORTS

80

56THE SMALLEST CIRCUITS 48 Carbon Nanonets Spark New Electronicsby George Gruner Random networks of tiny carbon tubes could make possible low-cost, flexible devices such as electronic paper and printable solar cells.

FANTASTIC VOYAGE 72 Less Is More in Medicineby A. Paul Alivisatos Sophisticated forms of nanotechnology will find some of their first real-world applications in biomedical research, disease diagnosis and, possibly, therapy.

56 The Promise of Plasmonicsby Harry A. Atwater A technology that squeezes electromagnetic waves into minuscule structures may yield a new generation of superfast computer chips and ultrasensitive molecular detectors.

80 Shamans of Smallby Graham P. Collins Like interstellar travel, time machines and cyberspace, nanotechnology has become one of the core plot devices on which sciencefiction writers draw.

64 The Incredible Shrinking Circuitby Charles M. Lieber Researchers have built nanotransistors and nanowires. Now they just need to find a way to put them all together.

Scienti c American Special (ISSN 1936-1513), Volume 17, Number 3, 2007, published by Scienti c American, Inc., 415 Madison Avenue, New York, NY 10017-1111. Copyright 2007 by Scienti c American, Inc. All rights reserved. No part of this issue may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording for public or private use, or by any information storage or retrieval system, without the prior written permission of the publisher. Canadian BN No. 127387652RT; QST No. Q1015332537. To purchase additional quantities: U.S., $10.95 each; elsewhere, $13.95 each. Send payment to Scienti c American, Dept. NT2007, 415 Madison Avenue, New York, NY 10017-1111. Inquiries: fax 212-355-0408 or telephone 212-451-8442. Printed in U.S.A.

w w w. S c i A m . c o m

SCIENTIFIC A MERIC A N REPORT S

3

COPYRIGHT 2007 SCIENTIFIC AMERICAN, INC.

Plenty of

There is plenty of room for practical innovation at the nanoscale. But rst, scientists have to understand the unique physics that governs matter thereBy Michael Roukesack in December 1959, future Nobel laureate Richard Feynman gave a visionary and now oft-quoted talk entitled Theres Plenty of Room at the Bottom. The occasion was an American Physical Society meeting at the California Institute of Technology, Feynmans intellectual home then and mine today. Although he didnt intend it, Feynmans 7,000 words were a dening moment in nanotechnology, long before anything nano appeared on the horizon. What I want to talk about, he said, is the problem of manipulating and controlling things on a small scale. . . . What I have demonstrated is that there is room that you can decrease the size of things in a practical way. I now want to

Room Indeedshow