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Foresight Update 2

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A publication of the Foresight Institute


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Nobel Paths to Nanotechnology

What path will be followed to the first assemblers?

Several paths lead to nanotechnology, and work contributing to one or more of those paths has won several recent Nobel prizes. Even without the motive of building assemblers, practical and academic motives have moved technology in directions that bring assemblers closer.

Chemistry, 1987

The 1987 Nobel prize for chemistry went to Charles J. Pedersen, Donald J. Cram, and Jean-Marie Lehn for developing relatively simple molecules that perform functions like those of natural proteins. Pederson synthesized what are known as "crown ethers," a family of molecules that selectively bind specific metal ions in solution, holding them in properly-sized internal hollows. Cram and Lehn have extended this work, using chemical techniques to synthesize a wide range of molecules that specifically bind other molecules. This sort of selective binding is a common protein function.

The molecular machinery of cells self-assembles though the selective binding of one protein to another. Other molecules that bind selectively to one another might likewise be used as a basis for molecular machinery, providing an alternative to proteins for building first-generation assemblers. The ongoing work of Cram, Lehn, and their coworkers may be of great importance to the development of nanotechnology.

If protein design remains too difficult, building initial molecular machines from non-protein molecules may prove an easier path. Myron L. Bender and Ronald Breslow have already made non-protein molecules that function as enzymes.

Physics, 1986

The 1986 Nobel prize for physics when to Gerd Binnig and Heinrich Rohrer for development of the scanning tunneling microscope (STM). This device, reported in 1982, uses vibration isolation, piezoelectric positioning elements, and electronic feedback to position a sharp needle near a conducting surface with atomic precision.

Assemblers, of course, will work by positioning reactive molecules to atomic precision to direct chemical reactions. Several persons familiar with Eric Drexler's work on assemblers (including Drexler, Conrad Schneiker, Steve Witham, and no doubt others) independently observed that, as Engines of Creation notes, mechanisms of the sort used in scanning tunneling microscopy "may be able to replace molecular machinery in positioning molecular tools," perhaps helping to build a first-generation assembler.

Suitable molecular tools remain to be developed. In a series of experiments, R. S. Becker, J. A. Golovchenko, and B. S. Swartzentruber have produced modifications on a germanium surface, measured as 0.8 nanometer wide. These features are thought to represent single atoms of germanium, electrically evaporated from a bare STM tip, with the large size of the features resulting from problems with STM resolution. At last report, they were unable to call their shot (that is, to put the atom in a pre-selected location), and the process did not work for the related element, silicon. The evaporation process requires that the STM tip be retracted from the surface.

Scanning tunneling microscopy also promises to be of use in characterizing molecules, since it can give atomically-detailed pictures of various surfaces. This could speed molecular engineering, helping designers to "see" what they are doing with greater ease. Little has been demonstrated as yet, however. It has been used neither to sequence DNA, nor to characterize unknown chemical structures. George Castro of IBM's Almaden Research Center reports that experimenters have thus far had difficulty detecting molecules on surfaces, to say nothing of determining their structures. Nonetheless STM and related technologies for microscopy and micro-positioning are well worth watching as possible aids to the development of nanotechnology.

Chemistry, 1984

The 1984 Nobel prize for chemistry went to Bruce Merrifield for developing the technique used for synthesizing the most complex, specific chemical structures now made. This technique, known as solid phase synthesis (or simply the Merrifield method) uses a cyclic set of reactions to extend a polymer chain anchored to a solid substrate. Each cycle adds a specific kind of monomer, building polymers with a specific sequence.

The Merrifield method is at the heart of the machines now used to manufacture specific proteins and gene fragments by chemical methods. It is thus central to protein and genetic engineering (either one of which could, in principle, proceed without the other). The Merrifield method could be used to make other polymers, perhaps including non-protein molecules with protein-like functions, such as specific binding and self-assembly. By providing multiple paths to complex molecular systems, the Merrifield method provides multiple paths to nanotechnology.

What path will be followed to the first assemblers, and hence to nanotechnology? It is hard to guess, today. Protein engineering will clearly suffice, because proteins already serve as the components of complex molecular machines. Micro-positioning technologies may help, though development of suitable molecular tools seems likely to prove the hard part of the task. Molecular systems like those explored by Cram and Lehn, together with synthetic techniques based on the Merrifield method provide a wealth of alternatives having many of the advantages of protein engineering, but fewer constraints. With that lack of constraints, however, comes a lack of knowledge, a lack of examples from nature. A reasonable guess is that several paths will be followed, and will contribute in a synergistic fashion. First-generation nanotechnology need not be based on any single class of molecule or device.

In considering this confusing wealth of possibilities, two points are important to keep in mind. The first is that multiple approaches multiply possibilities for success, bringing it closer: assemblers will arrive by whichever is, in practice, the fastest (a simple tautology!), hence difficulties with any single approach need not mean overall delays. The second is that how the first assemblers are built will make little long-term difference: crude assemblers will be used to build better assemblers, and the nature of nanotechnology will soon become independent of the nature of the initial tools. In short, this kind of uncertainty about the path ahead--stemming from a wealth of promising possibilities--gives confidence in the emergence of assemblers, without obscuring the nature of the subsequent nanotechnology.


Foresight Update 2 - Table of Contents

 

Hacking Molecules

Nanotechnology may seem remote. Molecules are invisibly small, and they differ from the familiar objects of daily life. Manipulating them with assemblers is essential to nanotechnology, but assemblers will take years to develop.

Computers, though, can bring nanotechnology closer, letting us design molecular systems using computer models, years before we have assemblers able to build them in real life. This design-ahead process seems sure to occur, but when will it begin? Roger Gregory of the Xanadu hypertext project argues that the answer to this is simple: Almost immediately.

If design-ahead were to require expensive facilities and major funding, it would need to wait for broad acceptance of the importance of nanotechnology, or even for a sense of its imminence. This might take years. But Gregory observes that the early stages of design-ahead need neither funding nor new facilities: personal computers and motivated hackers are enough. ("Hackers" is used here, not in the media's sense of computerish juvenile delinquents, but in the original sense of inventive technologists making computers jump through hoops.) The growth of amateur molecule-hacking may have major consequences for the emergence of nanotechnology.

David Nelson, chief technical officer at Apollo Computer, has plotted trends in computer price and performance. They follow a classic smooth exponential, with performance at a given price growing ten-fold every seven years or so. At this rate, good personal computers today have roughly the power of a seven-year-old minicomputer or a fourteen-year-old mainframe. There is every reason to expect this trend to continue for years to come. (Nanotechnology will eventually put many billions of today's mainframes into an air-cooled desktop package, but that is another story.)

Molecular modeling software--able to describe molecules and the forces that shape them--has advanced over the years while migrating into less and less expensive machines. After long residence on machines such as Digital Equipment Corporation's VAX minicomputers, it has now arrived on personal computers, such as the Macintosh. Prices are still high and offerings sparse, but the barrier to amateur molecular design work is being breached.

An article in Update 6 contains links to current information on molecular modeling available on the Web.

See also review of Chem 3D Plus by Eric Drexler, and links therein to current material, in
article in Update 11.

Can these computer models give accurate results? This depends on one's standard of accuracy, which in turn depends on one's goals.

In engineering, one need only have enough accuracy to distinguish between designs that do and don't work. In nanoengineering, as in ordinary engineering, designers will generally (though not always) aim to maximize such things as stiffness and strength, while minimizing such things as size, mass, and friction. A designer can often compensate for an inexact model by aiming for a large, favorable margin in the uncertain parameters. Software based on modern molecular mechanics models is fairly accurate even by scientific standards; it should be good enough to design a wide range of molecular machines, with substantial confidence in the results.

Molecular modeling software falls into various classes. At the low end are programs that just provide a three-dimensional software sketch pad for patterns of atoms in space. At the high end are systems of programs that do the sort of molecular mechanics mentioned above--that derive molecular shapes and energies from information about the interactions among atoms. (An example of the latter is MicroChem, a program for the Macintosh; we expect to have a copy of version 2.0 to review for the next issue.)

Present systems are expensive and may need some adaptations to make them more useful for the design of molecular machinery. Once suitable software is available at a reasonable price, however, we can expect to see the emergence of a community of molecule hackers. Interest in nanotechnology is high in the computer community, and electronic mail and bulletin board systems will make it easy for designers to swap ideas, designs, and criticisms. Once the process gets rolling, designs for molecular widgets--such as gears, bearings, shafts, levers, and logic gates--should accumulate at a good pace, spawning a lively informal competition to design the best. As computers and software improve, the complexity of feasible designs will grow.

A few examples of more recent molecular device designs:

The spread of amateur nanomachine design will spread an understanding of molecular machines and nanotechnology. It will spread the idea of design-ahead by demonstrating it in action. Within the nanotechnology community, it will provide a channel for creative activity having concrete results, ranging from pictures suitable for video animation to studies suitable for journal publication. It will give people a chance to pioneer future technologies today, while gaining the knowledge, skills, and experience needed to enter the field professionally, when serious research funding begins to grow. By helping people to visualize nanotechnology, it will aid foresight and preparation.

How fast will home molecule hacking get off the ground? It is hard to say, but the activity seems fun, valuable, and worth promoting. The hardware is here, and the software is within reach.

The Foresight Update plans to review software tools useful for molecular design. If you come across reviews or advertisements, or are yourself familiar with such tools, please send us information.


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MIT Seminars

The Foresight Institute will co-sponsor several events at MIT this January in cooperation with the MIT Nanotechnology Study Group. FI president Eric Drexler will lead a four-day seminar on foreseeable breakthroughs entitled "Nanotechnology and the Limits of the Possible." Topics will be covered roughly as follows--Monday: technical basis of nanotechnology, nanomachines, replicators. Tuesday: nanocomputers, thinking machines. Wednesday: applications such as cell repair machines for advanced medicine and life extension; space hardware. Thursday: consequences for war and peace, liberty; the challenge of survival.

Drexler will also lead a seminar on "Hypertext Publishing and the Evolution of Knowledge, " exploring FI's assertion that a suitable hypertext publishing medium (not just "a hypertext system") can speed the evolution of knowledge by aiding the expression, transmission, and evaluation of ideas, and that development of such a medium is a goal of first-rank importance. Technical and implementation issues will be addressed. See "Upcoming Events" for details on these meetings.

Foresight's current hypertext publishing efforts


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Media Coverage

Since May, nanotechnology coverage has appeared in the Washington Post Magazine, The Media Lab (a book by Stewart Brand), OMNI (an excerpt from The Media Lab), Bloomsbury Review, The World & I, Analog (in a lead editorial and a follow-on article), Space World, and SFWA Bulletin. Articles or columns are planned for the January Scientific American and an unspecified issue of Discover.


Foresight Update 2 - Table of Contents

 

Upcoming Events

MIT Hypertext Lecture/Discussion, leader Eric Drexler, Jan. 11, 2 pm, room 16-310, free. Co-sponsored by FI; see writeup in this issue.

MIT Nanotechnology Lecture/Discussion Series, leader Eric Drexler, Jan. 11-14, 7:30 PM, Room 66-110, free. Co-sponsored by FI; see writeup in this issue.

"Where is the Bottom?" MIT lecture by Prof. Ed Fredkin, speculations on physical processes at the smallest possible length, Jan. 21, 7:30 PM, AI Lab 8th floor playroom, 545 Tech Square, free. Sponsored by MIT NSG.

Technological Literacy, the Third National Science, Technology, Society Conference, Feb. 5-7, Arlington, VA. Registration $80. Sponsored/supported by AAAS and NSF, among others. Contact AAAS, 202-326-6500.

Space Development Conference, May 27-30, Stouffer Concourse Hotel, Denver, CO. Co-sponsored by FI. Includes nanotechnology programming; see writeup in this issue. Registration $60 through May 1. Contact Box 300572, Denver, CO 80218, 303-692-6788.


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FI Advisors

An initial Foresight Institute Board of Advisors has been formed, consisting of Marvin Minsky, MIT professor and co-founder of the field of artificial intelligence; Gerald Feinberg, Columbia professor of physics; and Stewart Brand, founder of the Whole Earth Review and a director of the Point Foundation.

Current Foresight Board of Advisors


Foresight Update 2 - Table of Contents

 

Executive Search

FI is still searching for an Executive Director. Friends of the Institute are requested to read the ad in this issue and wrack their brains for ideas on who can fill this role. If you think of a likely prospect, please call Chris Peterson at FI: 415-364-8609.


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Space Conferences Cover Nanotechnology

The L5 Society and its successor, the National Space Society, have been increasing annual conference coverage of nanotechnology every year since 1985; the Foresight Institute will be co-sponsoring their next meeting in Denver over Memorial Day weekend. As this issue goes to press, plans are still in flux, but we expect at least two formal sessions on nanotechnology as well as the usual informal discussions. We urge those of you who would like to meet the FI leadership--and other FI participants--to attend. Both technical and non-technical information will be presented. (See the "Upcoming Events" section for details.)

Explicit coverage at last year's conference in Pittsburgh began with a session chaired by FI president Eric Drexler, with speakers Marvin Minsky (MIT professor, co-founder of the artificial intelligence field, and FI Advisor), Hans Moravec (head of Carnegie Mellon's Robotics Lab) and James Bennett (FI Director and VP of American Rocket Company). Drexler gave an introduction to nanotechnology; Minsky gave a fascinating, indescribable talk.

Bennett discussed the impact of nanotechnology on space development: today space is valued for its properties of microgravity and Earth observation, but with nanotechnology, these features will become less important. Space will then be valued for its resources, which nanotechnology will help us to use: energy, materials, and room to grow.

Moravec examined trends in computation, pointing out that today's supercomputers have a computational capacity somewhere between that of a mouse-brain and that of an insect-brain. But an extrapolation of the smooth curve of progress in computation--starting at the turn of the century with mechanical calculators, through vacuum tubes, transistors and so on--indicates that we should expect supercomputers equivalent to a human brain shortly after the year 2000, and personal computers of that power shortly after 2020.

In a later session on nanotechnology, Drexler went into detail on mechanical nanocomputers (which if built could result in megabrain-equivalent PCs) and cell repair technology. Nanotechnology-oriented discussion also dominated two panels covering the financial and legal aspects of space settlement--reasonably enough, since the time frames for the two developments may be comparable. It's clear that the nanotechnology meme is making rapid progress in the space community, thanks to conference organizers such as Dale Amon (Chair, '87), Jill Steele (Chair, '88), and Laura Powers (Program Chair, '88).


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From Foresight Update 2, originally published 15 November 1987.


Foresight thanks Dave Kilbridge for converting Update 2 to html for this web page.



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