News Library 1999
Zyvex LLC announced on October 8, 1999, that Dr. Ralph Merkle has joined the company in the newly created position of Principal Fellow. Zyvex press release. Dr. Merkle remains a member of the Foresight Institute Board of Advisors. The following month, Dr. Merkle's nanotechnology web site, one of the earliest and still one of the best and most well known sources of information on the Web about nanotechnology, moved from http://nano.xerox.com/nano/ to http://www.zyvex.com/nano/. For the moment, the old URL's will forward to the corresponding new URL. To find the new page corresponding to the page on the old Xerox nanotechnology site, replace "nano.xerox" in the old URL with "www.zyvex". Thus http://nano.xerox.com/nanotech/hydroCarbonMetabolism.html becomes http://www.zyvex.com/nanotech/hydroCarbonMetabolism.html.
1999. Foresight Conference and Tutorial on Molecular Nanotechnology
The Seventh Foresight Conference on Molecular Nanotechnology was held October 15 -17, 1999 at the Westin Hotel in Santa Clara CA, preceded by an introductory Tutorial on Foundations of Nanotechnology on October 14.
1999. Foresight Perspectives Workshop Series. [This series has been postponed]
The Foresight Perspectives Workshops are a series of small, intensively supported, highly interactive full-day sessions, each focused on a specific topic of major importance in emerging technologies. Often, these topics are highly controversial.
1999. Foresight WeekendFall 1999 Senior Associates Gathering
The Fall 1999 Senior Associates Gathering was held September 17-19, 1999. No matter what your values are, achieving your goals depends on understanding where technology is heading. It's impossible to do this alone; there's far too much going on. Let's put our heads together, examine the rush of technology, and see what is to be done about it.
1999. "Group Genius" Weekend: Foresight for the Next 30 Years
The 1999 Foresight Gathering for Senior Associates of Foresight, IMM, and CCIT was held May 21-23, 1999.
1999. Foresight $40,000 Challenge Grant a success
In the 10 December, 1999 issue of Science Harvard University researchers report a new addition to the nanotechnology toolkit: tweezers made from carbon nanotubes [Philip Kim and Charles M. Lieber, "Nanotube nanotweezers" Science 286: 2148-2150]. Two multiwalled nanotubes each 4 µm long and 50 nm in diameter were attached to each of two independent gold electrodes mounted on a glass micropipette. Applying a bias of about 8 V caused the tweezer ends to close due to elastic deformation of the nanotubes, and applying voltage of the same polarity to both tips caused the tweezers to open. The researchers were able to pick up and manipulate silicon carbide nanoclusters (a bead about 500 nm in diameter) and gallium arsenide nanowires, and to measure their electrical properties.
The authors expect that technical refinements will allow them to make smaller nanotweezers that could manipulate even smaller objects. Perhaps we should not expect such tweezers to ever be capable of manipulating atoms or small groups of atoms, but we might expect the eventual manipulation of molecular building blocks. In an accompanying editorial (pp 2095-2096) Chad A Mirkin describes how the nanotweezers improve upon the limited manipulation capabilites of SPM tips and of earlier silicon microtweezers, and concludes that this demonstration is "an important step toward the development of a useful new tool for the nanotechnologist."
Once again the "news of the week" section of Chemical Engineering & News (December 13, 1999) featured a nanotechnology advance: "'Tweezers' added to nanotoolbox: carbon nanotubes attached to micropipette grasp nanoscale clusters and wires." C&EN quotes Daniel T. Colbert of Rice's Center for Nanoscale Science & Technology on the potential of the nanotweezers "These are not going to be the solution to assembling structures on a nanometer scale for potential applications. But they can be an important tool for assembling individual structures that we study scientificallya machine for building prototypes of interesting structures and characterizing them."
Researchers at Cornell University used an STM to bond a single carbon monoxide molecule to a single iron atom, forming a molecule of Fe(CO). In addition to imaging the product with the STM, the authors were able to use the STM for single molecule vibrational spectroscopy to characterize the bonds formed. The research was published in the Nov. 26, 1999, issue of Science: "Single-Bond Formation and Characterization with a Scanning Tunneling Microscope," H. J. Lee and W. Ho, Science 286: 1719-1722. From the authors' abstract:
A scanning tunneling microscope (STM) was used to manipulate the bonding of a carbon monoxide (CO) molecule and to analyze the structure and vibrational properties of individual products. Individual iron (Fe) atoms were evaporated and coadsorbed with CO molecules on a silver (110) surface at 13 kelvin. A CO molecule was transferred from the surface to the STM tip and bonded with an Fe atom to form Fe(CO). A second CO molecule was similarly transferred and bonded with Fe(CO) to form Fe(CO)2.
News of the achievement headed the "news of the week" section of the Nov. 29 issue of Chemical & Engineering News: "STM: an all-in-one tool Scanning instrument manipulates molecules, makes bonds, images products, and, now, measures molecular vibrations."
In an article entitled "It's a small, kinky world" on nature science update, Philip Ball writes of progress in manipulating carbon nanotubes into "genuine electrical circuits." He reports on research that Alan Johnson and colleagues from the University of Pennsylvania published in the journal Applied Physics Letters (November 8, 1999): "Single-wall carbon nanotube circuits assembled with an atomic force microscope" J. Lefebvre, J. F. Lynch, M. Llaguno, M. Radosavljevic, and A. T. Johnson Applied Physics Letters 75: 3014-3016. These authors report using tapping mode atomic force microscopy to manipulate carbon nanotubes, controllably cutting, moving, rotating, and placing them one on top of another. Further, they can add metal junctions to measure the electronic properties of the nanotube junctions that they've fabricated, and found that they form electron tunneling junctions, opening the possibility that nanotubes can be formed into electronic devices.
Following close on that announcement, Cees Dekker and his colleages extended earlier observations of electical diode behavior in nanotubes by demonstrating that individual kinked nanotubes do in fact exhibit diode behavior. It had been known that single wall nanotubes can be either metallic conductors or semiconductors, depending on the geometry of the tube, so it had been expected that junctions between tube segments with different geometries would behave as diodes, perferentially permitting current flow in one direction. In this research, the authors lay nanotubes across arrays of platinum electrodes and looked for individual nanotubes that had a kink, indicative of an intramolecular junction. They found that a metal-semiconductor junction behaves like a rectifying diode. MSNBC Technology News reported the advance: 'One small step' toward nanocircuits: Kinked molecules may contribute to giant leap in electronics. On the Academic Press InScight Web site: Nanotubes Make Tiny Diodes. The research article was published in the November 18, 1999 issue of Nature: "Carbon nanotube intramolecular junctions" Z Yao, HWC Postma, L Balents and C Dekker Nature 402: 273 - 276.
For a recent overview of the potential of nanotubes, written by Richard Smalley, 1996 Nobel Laureate in chemistry, see "Nanotech Growth" part of the special feature "R&D in the New Millennium" in R&D Magazine online.
"Virtually every technology that depends on electrons traveling over microscopic or macroscopic distances could be revolutionized by nanotubes, which combine high strength and thermal conductivity with unique electrical properties."
The technology section of the New York Times carried an article on November 1, 1999 reporting an impending revolution in molecular electronics: "Computer Scientists Are Poised for Revolution on a Tiny Scale." The article sets the tone of an imminent revolution from the first paragraph:
"Scientists at a variety of elite laboratories around the country are sharing a growing sense that they are on the brink of a new era in digital electronics. It will usher in a world of circuits no more than a few atoms wide, with a potential impact on computing, in terms of speed and memory, that may be too profound to fathom."
The article reports progress, much of it still unpublished in the technical literature, since the announcement last summer of a molecular logic gate by a team at Hewlett-Packard and the University of California at Los Angeles. One of the limitations of that discovery was that the molecular configuration could only be switched once; now, according to the article, a team from Yale and Rice will soon report a new molecular switch that can be switched reversibly. The article also brings word that other advances will soon be announced by other research teams. James C. Ellenbogen, a prominent molecular electronics researcher at Mitre Corp. is quoted as saying "In two to five years, you will begin to see functioning circuits which are of recognizable utility." Speaking of using self-assembly to cheaply fabricate molecular-scale circuits, Mark Reed, chairman of the electrical engineering department at Yale University, is quoted as saying "This should scare the pants off anyone working in silicon." This article reports the mood of the research community more than it reports any specific technical advances, and that mood is perhaps summed up by a quote from Paul Saffo, a researcher at the Institute for the Future, "It feels like we're a year before the invention of the transistor and we're asking: 'What does solid state look like?'"
The same day, a Yale University News Release announced "Yale Research Team First to Describe Molecular-Sized Memory Discovery has Implications for Drastically Reducing Cost of Computer Memory." The research team, led by Mark Reed of Yale and James Tour of Rice University, demonstrated "a memory element the size of a single molecule. This is the ultimate in size that one can achieve in microminaturization. The fabrication of the molecular memory was done using a method called 'self-assembly,' which has the potential to dramatically reduce cost." Detailed results are to be presented at the International Electron Devices Meeting in Washington, D.C. on Dec. 6, 1999. Mark Reed was further quoted as saying "With the single molecule memory, all a general-purpose ultimate molecular computer now needs is a reversible single molecule switch. I anticipate we will see a demonstration of one very soon."
Public Radio also spotlighted progress in molecular electronics, as reported by Foresight Update editor Richard P. Terra:
A report of progress on a different problem in molecular electronics comes from the EETimes online of November 15, 1999: "Chemical researchers build molecular computer"
"A molecular electronics research project at Mitre Corp. has achieved a milestone in the effort to build self-assembled molecular computers. Researchers James Ellenbogen and Christopher Love have invented chemical building blocks that support the operation of a digital half adder, which represents a new level of circuit complexity for the field."
A "dip-pen" nanolithography (DPN) announced in January 1999 (see below) has evolved to become a more sophisticated nano-plotter 9 months later. In the October 15, 1999 issue of Science: "Multiple ink nanolithography: toward a multiple pen nano-plotter" S Hong, J Zhu, CA Mirkin, Science 286: 523-525. By using the AFM tip to make registration marks near the area of interest, the authors, from Northwestern University, are able to return to an area where they have already made lines of molecules on the surface, and accurately lay down a second set of lines or dots, using either the same or a second type of molecule as ink. The lines that they draw vary in width from 15 to 80 nm, and additional lines can be added with a positioning accuracy of 5 nm. Nanostructures produced by this method might have useful electronic or catalytic properties, although they would not be atomically precise structures, of the sort needed for molecular manufacturing. The method is, however, fairly rapid; an accompanying editorial on p. 389 of the same issue shows a 115-word paragraph from Feynman's famous 1959 talk foreshadowing nanotechnology written with lines 60 nm wide, and produced in only 10 minutes by the nano-plotter.
Every living organism, from bacteria to mammals, contains within each cell tens of thousands of ribosomes, the organelle that joins hundreds of amino acids together in a specific sequence to form each of the mryiad protein molecules that make the cell function, in accordance with the genetic code contained in the cell's DNA. Ribosomes are complex organelles, formed from two non-identical subunits, one large and one small, and composed of at least three distinct RNA molecules and more than 50 different proteins, totalling several million daltons, with bacterial ribosomes somewhat smaller than the ribosomes of higher (eukaryotic) organisms. Ribosomes are irregular in shape, and the maximum dimension in each direction for a bacterial ribosome is about 210 Å (21 nm). That these molecular machines, formed only from folded chains of RNA and protein molecules, could perform such a complex function, was one of the early inspirations for nanotechnologists:
"Simple molecular devices combine to form systems resembling industrial machines. In the 1950s engineers developed machine tools that cut metal under the control of a punched paper tape. A century and a half earlier, Joseph-Marie Jacquard had built a loom that wove complex patterns under the control of a chain of punched cards. Yet over three billion years before Jacquard, cells had developed the machinery of the ribosome. Ribosomes are proof that nanomachines built of protein and RNA can be programmed to build complex molecules."
Deciphering the structure of the ribosome has been an intense challenge to biologists and physical scientists for several decades, culminating in several x-ray diffraction studies published during August and September of 1999 that begin to show near-atomic resolution structures for bacterial ribosomes. Although these structures do not yet provide enough information to show in detail how the ribosome works, it is not only clear that such information will soon be forthcoming, but it is already clear that the ribosome is much more machine-like in its operations than many scientists would have believed when Engines of Creation was written.
The August 26, 1999, issue of Nature presents reports by two different teams of researchers on the structures of each of the two ribosomal subunits: "Structure of a bacterial 30S ribosomal subunit at 5.5 Å resolution" WM Clemons Jr, JLC May, BT Wimberly, JP McCutcheon, MS Capel, and V Ramakrishnan, Nature 400: 833-841; "Placement of protein and RNA structures into a 5 Å-resolution map of the 50S ribosomal subunit" N Ban, P Nissen, J Hansen, M Capel, PB Moore, and TA Steitz, Nature 400: 841-847. Since an average-sized atom is about 3 Å in diameter, neither study allows exact identification of atomic positions in the structures, but since much other structural information is available about subfragments of each subunit, a fairly clear picture emerges of the structure of much of each subunit. Further, both teams expect that the crystals they are studying will ultimately give data to 3 Å resolution.
In an accompanying appraisal of the two research articles entitled "Mechanics of the ribosome," R Garrett (pp. 811-812) concludes "The ribosome, together with its accessories, is probably the most sophisticated machine ever made. All its components are active and moving, ... the next decades will be dedicated to studying the machine's movements."
The next step was presented in the September 24, 1999 issue of Science, in which the crystallographic structure of the complete ribosome was presented. Although the resolution was lower (only 7.8 Å-resolution) than in the earlier studies of the separated subunits, the study of the whole ribosome shows the interactions between the subunits and with the messenger RNA and transfer RNAs during protein synthesis. "X-ray crystal structures of 70S ribosome functional complexes" JH Cate, MM Yusupov, GZ Yusupova, TN Earnest, HF Noller, Science 285: 2095-2104. A second paper by the same team in the same issue identifies a specific RNA-protein bridge involved in the interaction between the two subunits. "Identification of an RNA-protein bridge spanning the ribosomal subunit interface" GM Culver, JH Cate, GZ Yusupova, MM Yusupov, HF Noller, Science 285: 2133-2135.In press releases from the team involved in the Science papers, Noller, the senior author, is quoted as saying "The ribosome appears to be a dynamic molecular machine with moving parts and a very complicated mechanism of action," and ""Our images also suggest very strongly that the ribosome is a machine -- and a very complex one with many moving parts."
Molecular machine systems will presumably need to be powered by molecular motors. Indeed, biological molecular machinery provides abundant and diverse examples of molecular motors, which have become of increasing interest to nanotechnologists [for example, from last year's Foresight Conference on Molecular Nanotechnology, see "The question of the mechanism of molecular motors", "using optical tweezers to study biological motors", "Biotechnology/Biomotors", and especially "Constructing biological motor powered nanomechanical devices"].
However, biology no longer has a monopoly on molecular motors. The September 9, 1999 issue of Nature contained two papers from two research collaborations demonstrating prototype synthetic molecular motors. An editorial accompanying these two papers notes that there have been various examples to date of synthetic molecular actuators that are best described as "switches" or "shuttles" because they respond to external forces by switching between two states. But there have been no examples outside of biology of true molecular motors, capable of continuous, unidirectional motion. Each of the two papers points to a different promising route toward the goal of a true molecular motor, although neither quite reaches this goal. The editorial notes that work on these synthetic motors should lead to better understanding of the mysteries of how biological molecular motors work, but the more interesting conclusion is: "...the results of these two groups provide further confirmation that molecular scale engineering is slowly edging toward reality."
In the first of these papers, "Unidirectional rotary motion in a molecular system," by TR Kelly, H De Silva and RA Silva of Boston College [Nature 401:150-152] the authors "dscribe a molecule that uses chemical energy to activate and bias a thermally induced isomerization reaction, and thereby achieve unidirectional intramolecular rotary motion." The molecular system they use has only 78 atoms, and the molecular fuel that supplies the chemical energy for rotation is carbonyl dichloride, which contains only 4 atoms. The molecular system has two components: a three-bladed triptycene that is connected by a single carbon-carbon bond to a bulky helicene component that is asymmetric, or chiral, in shape so that clockwise rotation can be distinguished from counterclockwise rotation. Also, the bulky helicene acts as a friction brake such that spontaneous rotation about the "axle" single C-C bond is inhibited, but not prevented, compared with rotation about a typical single C-C bond. To achieve undirectional rotation, the chemical energy of the carbonyl dichloride is used to lower the energy barrier to rotation in the clockwise direction only. Using several chemical reactions that occur over a period of hours, carbonyl dichloride first reacts with one blade of the triptycene and draws it into strained contact with part of the helicene, forming a distorted, high energy conformation of the molecule that is then thermally driven past the frictional brake. Then chemical cleavage of the bond originally formed using the carbonyl dichloride results in a conformation in which the triptycene has rotated 120 degrees from its original position. One third of a rotation is several hours not exactly a practical motor, but an important demonstration of principle.
The second paper, "Light-driven monodirectional molecular rotor," by N Komura, RWJ Zijlstra, RA van Delden, N Harada, and BL Feringa of the University of Groningen in the Netherlands and Tohoku University in Japan [Nature 401:152-155] reports "...repetitive, monodirectional rotation around a central carbon-carbon double bond in a chiral, helical alkene, with each 360° rotation involving four discrete isomerization steps activated by ultraviolet light or a change in the temperature of the system." The molecular rotor in this case is even smaller than the molecule in the first paper (but with a much longer name). Here two identical halves of the molecule are connected by an "axle" consisting of a carbon-carbon double bond. The central double bond does not allow free rotation, but does provide for a 180° flip (isomerization) between a "cis" and "trans" form of the molecule. The molecule halves each consist of three fused rings with a methyl group substituent on the ring nearest the central double bond. In the cis isomer the two halves are oriented so that the methyl groups are on the same side of the double bond; in the trans isomer the methyl groups are on opposite sides of the double bond. The molecular halves are bulky enough that they do not lie flat on each side of the central double bond, but rather twist into a helical shape. Because each half of the molecule contains a chiral center, the cis and trans forms of the molecule each exist in two distinct forms: one in which the two halves of the molecule are in a right-handed helix (designated P), and one in which they are in a left-handed helix (designated M). Thus there are four conformational species of the molecule, which the authors designate as (P,P)-trans-1, (M,M)-cis-2, (P,P)-cis-2, and (M,M)-trans-1. Irradiation of (P,P)-trans-1 with UV light of wavelength 280 nm at a temperature of -55°C causes the transition to (M,M)-cis-2. When the solution is warmed to 20° a fast, irreversible thermal conversion to (P,P)-cis-2 occurs. Irradiation of this third species with UV light of wavelength 280 nm converts it to (M,M)-trans-1. Warming this species to 60° causes an irreversible thermal conversion to the starting material, thus providing a complete 360° rotation about the central double bond. The reason that for botht he cis and trans isomers the P,P isomer is more stable than the M,M isomer appears to be that the methyl substituents sterically interfere more in the M,M isomers, while they are oriented out of the way in the P,P isomers. Thus one complete rotation is driven by two light-induced 180° rotations about a double bond (cis-trans isomerizations), each of which inverts a sterically favored helical conformation to the unfavored conformation. The energetically downhill conversion to the favored helical conformation prevents reversal of the cis-trans conversion, thus insuring unidirectional rotation.
The September 11, 1999 issue of Science News covered the two papers with an article entitled "Molecular motors spin slowly but surely."
The above molecular motor demonstrations were noted by various reports on Web news sites:
Work with biological molecular motors also made news. The September 1999 issue of Nanotechnology, a special issue featuring papers from the 6th Foresight Conference on Molecular Nanotechnology, included "Constructing nanomechanical devices powered by biomolecular motors" by Carlo Montemagno and George Bachand (pp 225-231) [draft version available here]. Web coverage of the publication of this work included the following:
More detailed understanding of another biological molecular motor came in a report from Princeton scientists. Biophysicist Steven Block and his collaborators showed that "... a molecular motor called kinesin, a protein that travels along the microtubules that form the skeleton of cells, ... burns exactly one ATP molecule for each 8 nm steps it takes, no matter how much resistance it faces."
Fullerene molecules encapsulating a few metal atoms might have a number of novel and useful material properties, but until now it has been difficult to prepare these molecules in high yields. "Small-bandgap endohedral metallofullerenes in high yield and purity" published in the September 2, 1999 issue of Nature 401:55-57 reports that the introduction of a small amount of nitrogen into an electric-arc reactor results in the efficient encapsulation of a metal nitride (an N atom and 3 metal atoms). In the words of the authors: "We expect that our method will provide access to a range of small-bandgap fullerene materials, whose electronic properties can be tuned by encapsulating nitride clusters containing different metals and metal mixtures."
Quantum chemistry is one of the intellectual foundations of computational nanotechnology. Although molecular dynamics based upon classical physics suffices for some calculations, in other cases involving making and breaking chemical bonds, the insights of quantum chemistry are necessary to explore how molecular machine systems would function. Electron orbitals have been described computationally by quantum chemistry theory, but until now these orbits have not been experimentally imaged. This situation changed with the publication of "Direct observation of d-orbital holes and Cu-Cu bonding in Cu2O" in the September 2, 1999 issue of Nature 401:49-52.
In the words of the press release of the authors' university:
Last summer a team of researchers drawn from UCLA and Hewlett-Packard Laboratories reported a massively parallel computer named Teramac with an novel, defect-tolerant architecture permitting it to route around hardware defects [See Update 34 - http://www.imm.org/Reports/Rep003.html#DefTolComp]. Teramac was fabricated using conventional silicon-based CMOS technology, but was proposed as a useful model for future computers in which chemically synthesized (self-assembled) electronic components would be much more numerous (moles of components) and inexpensive, but not all perfect, compared with conventional silicon-based CMOS technology.
This summer, the same team reported a major step towards fabricating molecular electronic components that could be used in a Teramac-like defect-tolerant architecture "Electronically configurable molecular-based logic gates" in the July 16, 1999 issue of Science 285:391-394. The authors describe their ultimate goal as a chemically assembled electronic nanocomputer (CAEN), which will have the following requirement. "Thus, to be economically viable, CAENs must be assembled from extremely inexpensive wires and configurable switches with simple techniques that are amenable to mass production." The components that they report fabricating are a hybrid - a layer one molecule thick, deposited between micron scale wires fabricated by conventional lithography, that forms a junction that can be (irreversibly) configured only in one direction. One example they report is an array of six devices (junctions) in which each junction contains several million rotaxane molecules sandwiched between two metal wires a few microns thick. A major experimental accomplishment was that the molecular monolayer survived the deposition of the top electrode of the junction. Any junction could be selectively opened by applying an oxidizing voltage to that junction, an irreversible event with the rotaxane molecules used. The authors were then able to configure these linear arrays of devices into AND and OR wired-logic gates. Testing such a device revealed a response much better than would be expected for conventional resistors - a factor of 15 difference in current flow between the high and low states. "This nonlinearity is extremely useful because it should allow combination of wired-AND and wired-OR gates with each other to create more complex and intrinsically nonlinear logic circuits." In another experiment, the authors demonstrated that they could reconfigure a three-input OR-gate into a two-input OR-gate. Although the devices reported are only molecular in one dimension, the authors state their belief that they can be scaled down to molecular dimensions in all three dimensions. "The devices presented here provide a compelling argument that molecular switch devices may play an important role in future computational technologies."
An accompanying editorial (pp. 313-314) quotes other experts in the field as saying that this "novel" approach could "have a tremendous impact on the semiconductor market." The two most pressing challenges are to (1) find an organic molecule that can be reversibly switched between states, and (2) reduce the size of the wires to nanometer dimensions, perhaps by replacing metal wires with carbon nanotubes. James Heath, the corresponding author of the research report is quoted as saying that, if a computer could be built from nanotube wires and molecular switches, "you would get 100 workstations in a grain of sand." Chemical and Engineering News (July 19, 1999, pp. 11-12) also hailed a "Key step made toward molecular computing." They reported "The first organic molecule-based electronic components that perform some of the same basic logic operations used by Intel Pentium chips and other computer microprocessors have been developed by a collaborative group in California." They quote molecular electronics expert James Tour as describing the HP-UCLA result as "a really significant achievement" and "an important stepping stone toward a molecular electronic system." They also quote Heath as saying that organic molecule-based computing "would require almost no energy" and could run 109 times faster than a silicon-based computer.
The self-assembled molecular logic gate has been hailed on the Web as a major advance in nanotechnology.
Molecular electronics has rightly received attention as a very promising, relatively near term, application of nanotechnology, and one that promises great impact, both technologically and economically. Further, the needs of the computer industry will support more intensive research in nanoscale science and nanotechnology, and improved computers that result a decade or so from now will enable more computational nanotechnology research. But molecular manufacturing will require the ability to build molecular machine systems, not just molecular circuits.
Those who have followed Foresight's coverage of nanotechnology research for some time will be familiar with the use of DNA to fabricate nanostructures and nanodevices [see for example "A Nanomechanical device based upon conformation change in rigid DNA structure"]. Other researchers have been interested in the possible use of DNA molecules as wires in nanoelectronic devices, but there has been much controversy whether DNA is electrically conducting or not.
Proposing a new explanation for how electronic charge transfer occurs in strands of DNA, a research team from the Georgia Institute of Technology has reported "that electrical charge moves through the DNA bases by creating temporary distortions in their structure as the strands naturally flex. The work suggests that the charge transport process is much more complicated than previously believed."
The National Science Foundation (NSF) agreed to help fund a consortium of institutions to establish a new Nanobiotechnology Center (NBTC) at Cornell. "... the award to Cornell, Princeton and Oregon Health Sciences universities and to the Wadsworth Center of the New York State Department of Health will be coupled with support from the State of New York, industry, private foundations and Cornell University." The funding of the NBTC is one of five new national science-and-technology centers to receive a total of almost $94 million.
The advances listed below have drawn notice as significant advances in nanotechnology. Some of them appear to be directly leading toward developing molecular machine systems, and eventually molecular nanotechnology; others are more specialized examples of nanofabrication technology that may find use primarily in intermediate applications or in advancing enabling technologies.
Molecular switches: A tension-activated protein switch
De novo design of a larger protein with a well-defined structure
Buckyballs made to emit light
MEMS technology produces "nanoharp"
Dr. Richard Smalley, Gene and Norman Hackerman Professor of Chemistry and Professor of Physics at Rice University and 1996 Chemistry Nobel Prize Winner testified on May 12, 1999, at the Senate Science, Technology and Space Subcommittee hearing to examine incentives and barriers created by the federal government in bringing new technologies to the marketplace: "Emerging Technologies in the New Millennium." This hearing had a broader focus than nanotechnology, and Smalley addressed the potential of nanotechnology, and included in his written material excerpts from a draft version of Nanotechnology A Revolution in the Making Vision for R&D in the Next Decade, a report of the Interagency Working Group on Nanoscience, Engineering, and Technology, presented to the OSTP Committee on Technology, March 10, 1999.
The following month Smalley was joined by Foresight Advisor Dr. Ralph Merkle and two other science and technology luminaries in testifying to a hearing concerned solely with nanotechnology before the House Subcommittee on Basic Science "Nanotechnology: The State of Nano-Science and Its Prospects for the Next Decade."
This hearing appears to be part of a general interagency effort (headed by Mike Roco of NSF) to increase funding for nanotechnology.
The EE Times carried a story on the hearing entitled "Congress set to boost nano funding"
Richard Smith, Senior Analyst at Coates and Jarratt, has posted a report on the hearing:
Dr. Richard Smalley, Gene and Norman Hackerman Professor of Chemistry and Professor of Physics at Rice University and 1996 Chemistry Nobel Prize Winner, recently testified before Senate and House committees on nanotechnology (see above). Attached to Prof. Smalley's written statements was the draft executive summary of "Nanotechnologya Revolution in the MakingVision for R&D in the Next Decade", a report of the Interagency Working Group on Nanoscience, Engineering, and Technology, presented to the OSTP Committee on Technology, March 10, 1999.
Budget request from the President could come as early as next year.
by Richard Terra
The possibility of a high-level national initiative in nano-scale science and nanotechnology was the focus of a three-day workshop, "Vision for Nanotechnology R&D in the Next Decade," held at the National Science Foundation (NSF) in Arlington, VA, on 27-29 January. The workshop was organized by the Interagency Working Group on Nano Science, Engineering & Technology (IWGN).
According to a report in The Federal Technology Report (11 Feb 1999), nearly 100 specialists from federal and national laboratories, universities and industry participated. Presentations were made by staff from a variety of federal funding agencies with relevance to nanotechnology, including the NSF, NASA, the National Institutes of Health (NIH) and the departments of Energy and Defense.
The NSF also held a public forum, "From Scientific Discovery to the Nanotechnology of Tomorrow," during the Sixth Foresight Conference last November. Reports on the forum appeared in the Update 35.
According to the announcement published in The Federal Register last December, the stated goal of the January Arlington workshop was "To identify goals, opportunities and policies pertaining to support for R&D in nanotechnology and related fields at NSF and other U.S. Government agencies." The agenda included discussion on issues, opportunities, and future directions for nanotechnology research and development.
Following the workshop, senior federal officials are considering organizing a national nanotechnology initiative that could be included next year in the President Clinton's federal budget request for Fiscal Year 2001. Vice President Al Gore announced a similar initiative, the Information Technology Initiative for the 21st Century (IT2), last month, which will be included in the President's FY-2000 budget request.
Thomas Kalil, a senior director for economic policy at the White House National Economic Council, issued a call for such an R&D effort organized at the national level during the workshop. Such an initiative, said Kalil, would have five major components: Increased investment; high-level attention; multi-agency cooperation; a rationale for the topic being a high priority; and a strategy that articulated "some relationship between the means and the ends."
The range of potential applications for nanotech devices or systems, and the benefits they may offer is impressive in its breadth, Kalil told workshop attendees. It offers "potential for a huge, pervasive impact on our economy [and] quality of life and requires and will enable advances in many disciplines," he said.
Kalil pointed to the increasing activity and growing interest among researchers and a "flurry of recent results" in the burgeoning field of nanotechnology. He also recalled the 1992 Senate hearings held by then-Senator Al Gore, which were the first congressional hearings on nanotechnology. K. Eric Drexler, a research fellow at the Institute for Molecular Manufacturing and a Foresight director, testified at those hearings. Dr. Drexler's written testimony appeared in Update 14; and a transcript of his oral testimony appeared in Update 15.
Kalil also reminded workshop attendees of an April 1998 forecast by Neal Lane, the president's Science and Technology Advisor, that nanoscale science and engineering was the "most likely area of science and engineering to produce the breakthroughs of tomorrow." (See Update 33).
A report based on presentations and other contributions from workshop attendees during breakout sessions is in preparation. Their recommendations on the size, scope, directions and components for a National Nanotechnology Initiative will likely be delivered to OSTP and NSTC officials in the coming months. The next step would be a formal proposal drafted by NSTC, to be considered for inclusion in the administration's science and technology budget planning process for FY 2001.
The possibility was also raised that the initiative could be considered as an additional program during FY-2000, if the appropriate opportunity arose.
A "window of opportunity" for getting a national nanotechnology initiative underway remains open, said Duncan Moore, associate director for technology at the White House Office of Science and Technology Policy. But Duncan cautioned that such an initiative would require a well-thought-out strategy, with a series of technical and commercial checkpoints. It would also require support within industry, academia, and federal agencies and research institutions.
The workshop did not develop a specific figure for funding the initiative, but some numbers mentioned ranged as high as $150 million.
Ned Seeman, winner of the 1995 Feynman Prize in Nanotechnology, has scored a second major advance in less than a year along a potential road toward molecular nanotechnology that involves making devices from branched DNA molecules. In the first advance, last August he and his colleagues reported in Nature that DNA junctions could be made more rigid by incorporating double crossover molecules of DNA (see "DNA Crystal Design" in IMM Report Number 6). This advance last year made possible the realization this year of an earlier idea of Dr. Seeman's (see one of his papers from 1989) to use the reversible change between the B and Z forms of DNA to drive a nanomechanical manipulator. Realization of this B <--> Z DNA nanomanipulator concept was blocked until now by the excessive floppiness of the DNA junction molecules that were available prior to using double crossover molecules of DNA (see Note 1 from Dr. Seeman).
The more recent advance was reported this week in the Jan. 14, 1999, issue of Nature ["A nanomechanical device based on the B - Z transition of DNA," by Chengde Mao, Weiqiong Sun, Zhiyong Shen & Nadrian C. Seeman, Nature 397: 144-146.] The device consists of two rigid DNA 'double-crossover' molecules connected by a long DNA helix of 4.5 double-helical turns. A segment of this central helix is a specific sequence of DNA base pairs that is known to be susceptible to switching from the normal B-form of (right-handed) DNA to Z-form (left-handed) DNA when the solution is changed by increasing salt concentration or adding certain small effector molecules, cobalt hexamine in these experiments. The ends of all helices are closed by short sections of single strand DNA so that the entire structure is made from three cyclic strands of DNA that are multiply concatenated to link the rigid end structures with the central helix containing the Z-DNA section.
To measure the effects of the B <--> Z DNA transition, two fluorescent dye molecules (fluorescein and Cy3) were attached to hairpin loops of DNA near the center of the construction. The distance between these molecules was expected from molecular modeling calculations to increase from 5.1 nm to 7.0 nm as the transition from B to Z DNA caused the central helix to unwind by 3.5 helical turns.
The actual increase in separation was measured by fluorescence resonance energy transfer, which is proportional to the inverse sixth power of the distance between the dye molecules. The experimental results indicate an increase in separation between the dye molecules from 7.0 nm to 8.9 nm when the cobalt hexamine is added. No change was seen in a control construction in which the central helix was altered to a sequence that would not change to Z-DNA. The discrepancy between modeling and experiment in the absolute values of the distances is probably a result of approximations in the modeling programs or in interpreting the experiments. However, the excellent agreement between experiment and modeling for the increase in distance under Z DNA-promoting conditions is compelling evidence that a mechanical change was produced. The authors conclude:
"It should be possible to incorporate this mechanical control in any figure or array produced by DNA nanotechnology, so long as a free swivel containing proto- Z DNA can be included in the design. In addition, it should be possible to change the relative positions of proteins or other large molecules connected to DX [DNA double crossover] units, in the same way that the relative positions of fluorescent dyes have been changed here. This capability should enable the study of proximity effects in chemical and biological systems. It is difficult to predict whether this system could also be used to power a nanoscale motor; we have shown that the B <--> Z transition can provide two equilibrium structures in different positions, but the ability to transmit force depends on the structural and dynamic features of the transition itself."
At this early stage of development, it is not known whether the precision with which these DNA nanomanipulators could be programmed to deliver a precise force at a precise position would be adequate for mechanosynthesis (see Note 2 from Dr. Seeman); however, designs that use such mechanisms to assemble molecular building blocks might be very interesting.
Dr. Seeman's latest advance has rightly attracted a great deal of attention. The following url's give the New York University Press Release and three Web news sources that report the result:
Notes (clarifications provided by Dr. Seeman and Dr. Drexler):
Molecular Manufacturing Enterprises, Inc. announces nanotechnology tools firm Angstrom Tools, Limited
In a letter to Foresight from Steven C. Vetter, President, Molecular Manufacturing Enterprises, Inc.:
R&D Magazine Online's feature on "R&D in the New Millennium" presents essays on the future of R&D in which several prominent scientists cite the potential impact of nanotechnology:
The November 8, 1999, special issue of Time Magazine focused on the theme "Beyond 2000: Your Body, Our Planet." The sidebar to the article entitled "Will Robots Make House Calls?" continued the theme of robotic medicine by briefly looking at nanoscale robots "...and WIll They Go Inside Us?" "Given the promise of nanotechnology, it's a safe bet," concluded Time. The side bar was well-illustrated and gave a good account of the possibilities of nanomedicine:
Nanostructure Science and Technology: R&D Status and Trends in Nanoparticles, Nanostructured Materials, and Nanodevices, a worldwide study prepared under the guidance of the IWGN, NSTC (The Interagency Working Group on NanoScience, Engineering and Technology of the National Science and Technology Council Committee on Technology) was made available on the Web during September, 1999. From the abstract:
"This report reviews the status of research and development in nanoparticles, nanostructured materials, and nanodevices worldwide, with particular focus on comparisons between the United States and other leading industrialized countries. Topics covered include particle synthesis and assembly, dispersions and coatings of nanoparticles, high surface area materials, functional nanoscale devices, bulk behavior of nanostructured materials, and biological methods and applications. The final chapter is a review of related government funding programs around the world. The report also includes site reports for visits conducted by the panel to leading research laboratories in Japan and Europe."
The report can be found at: http://itri.loyola.edu/nano/toc.htm
A related document, Nanotechnology, Shaping the World Atom by Atom, prepared by the National Science and Technology Council (NSTC) Committee on Technology and The Interagency Working Group on Nanoscience, Engineering and Technology (IWGN) is available as a 2.1 Mb PDF document at http://itri.loyola.edu/nano/IWGN.Public.Brochure/
The American Institute of Physics Bulletin of Science Policy News has reprinted an op-ed from the October 18, 1999 issue of the Washington Post in which former House Speaker Newt Gingrich calls for a doubling of federal spending on scientific research in the next five years. Gingrich cites nanotechnology as one of five areas in which "major scientific breakthroughs ... will transform our lives."
FEED Magazine's special issue on 21st Century Inventions (November 8, 1999) begins with "Thinking Small Mark Pesce on molecular-scale manufacturing, the gray goo problem, and how nanotechnology will change the world as we know it." The editors characterize nanotechnology as "arguably the next century's most mysterious and powerful breeding ground for invention." Pesce's essay explores the roots of nanotechnology in Richard Feynman's famous 1959 talk, through Marvin Minsky's thinking about the future during the 70's, leading to Eric Drexler crafting his ideas about nanotechnology and spreading them to his fellow students at MIT, leading to the publication of Engines of Creation. Pesce describes his own interactions with Drexler during this time:
"I went to one of these salons d'idées, and by the end of the evening considered Drexler a prophet of the next age of Man, a time when nearly anything seemed possible. Nanomachines or, more commonly, nanites which could repair cellular-level damage and guarantee a nearly eternal, healthy existence; kitchen appliances which, fed on garbage, produced an endless supply of high-quality "meat"; an inexhaustible supply of incredibly strong building materials made of diamond, grown in forms of any conceivable volume. Drexler promised a material world nearly entirely subservient to the whim of the human imagination, programmed according to need."
After explaining why developing self-replicating assemblers is crucial to the above goals, Pesce comments on progress described at last month's Seventh Foresight Conference on Molecular Nanotechnology, and on the recent publication of Robert Freitas's Nanomedicine, and then compares the state of nanotechnology today with the early days of the personal computer revolution:
"The Homebrew Computer Club gave Steve Jobs and Steve Wozniak a platform to share their work and sell the Apple I, gave Lee Felsenstein the opportunity to demonstrate the first portable computers, and legitimized the amateur in a field dominated by corporate "big-iron" interests. Foresight, the IMM, and other nanotechnology interests have a similar feel hackers on the edge of another revolution. And hackers are necessary to its development for many of the same reasons."
The Web site of the San Jose Mercury News carried an article on the growing importance of nanotechnology "Ultra-tiny machines are becoming big hope for scientists," posted on November 1, 1999. The article cites recent Congressional hearings on increasing funding for nanotechnology, then points to research in molecular motors [both biological (the work of Montemagno at Cornell) and chemical (the work of Kelly at Boston College)], to the molecular wheels demonstrated by James Gimzewski at IBM, to the "nanopen" work of Mirkin at Northwestern University. The consensus of researchers seems to be that "nanotechnology stands today where television was in the 1930s and transistors in the 1950s."
In an article posted on October 15, 1999, immediately before the opening of the Seventh Foresight Conference on Molecular Nanotechnology, San Jose Mercury News technology columnist Dan Gillmor concluded that nanotechnology is moving solidly into the realm of mainstream science: "Nanotechnology: from science fiction to fact" After considering the many implications of a mature molecular manufacturing technology, Gillmor muses:
"The brave new world of biotechnology and beyond" appeared on the Christian Science Monitor Web site on October 28, 1999. "Genetic engineering and nanotechnologies will not only change our world, but perhaps even bodies." As examples of nanotechnology currently under laboratory development, the article cites the work of researchers Carlo Montemagno of Cornell University and Viola Vogel of the University of Washington on adapting biological motor molecules for use in artificial molecular machines. Nobel laureate Richard Smalley is quoted on the impact that nanotechnology will have: "We're heading in a direction that in the next 50 to 100 years, we could actually change the nature of human beings." Smalley is further quoted, "It will be possible, it seems almost inevitable, to vastly extend the length of human life." To emphasize the importance of nanotechnology research, the article cites a general interagency effort (headed by Mike Roco of the National Science Foundation) to double U.S. government funding for nanotechnology to $500 million annually over the next three years.
A chemistry WebMagazine Reactive Reports featured an article "All aboard the nanotrain" on the work presented by Russell J. Stewart of the University of Utah at the 1999 Foresight Conference on Molecular Nanotechnology. Stewart is adapting the biological motor protein kinesin to interact with and power silicon micromachinery.
"How Nanotechnology Will Change the World," a CNET Special Report that appeared October 20, 1999, describes how molecular nanotechnology "will change the world in ways we can barely begin to imagine" during the next 50 years. Assemblers will revolutionize manufacturing by precisely manipulating atoms and molecules, as computers manipulate digital bits, to build complex objects, including copies of themselves. The results will range from "the end of disease; even immortality" to "specialized killing machines that could be built and dispatched in a day." The article concludes that "The road to mastering nanotechnology may be long and winding, but there is no doubt that getting there will be interesting."
The Online News edition of the Pittsburgh Post-Gazette on October 11, 1999, carried the article "Tiny molecules called nanotubes have scientists dreaming big," which focused on the potential of carbon nanotubes in making molecular-size circuits, and in storing hydrogen or in acting as sieves to separate different isotopes of hydrogen.
"Immortality on IceCryonics May Offer Life After Death for Those Willing to Wait." A story on the Fox News Web site dated October 8, 1999, presents a few of the approximately 700 "extremely optimistic Americans" who have signed up to be cryonically suspended upon their deaths, including Foresight Advisor Ralph Merkle. The article presents both the hope that future molecular nanotechnology will be able to repair the damage caused by freezing, and the skepticism of some scientists based upon the [irrelevant] fact that current technology cannot repair damage caused by freezing.
In its August 30 1999 issue, Business Week "cut loose and went nonlinear" to compile "21 Ideas for the 21st Century." These provocative essays are available online at http://www.businessweek.com/1999/99_35/b3644001.htm, and cover several topics of interest to Foresight members. The one on nanotechnology starts: "Molecular machines aren't fantasy. Just ask the Pentagon. In the 2020s, you may be able to buy a 'recipe' for a PC over the Net, insert plastic and conductive molecules into your 'nanobox,' and have it spit out a computer."
The American Institute of Physics Bulletin of Science Policy News reports White House and Congress Support for Nanotechnology
On July 7, 1999, the American Institute of Physics Bulletin of Science Policy News reported that "one area of research that is beginning to come in for special interest from the White House and Congress is nanotechnology ..."
Special issue of TIME Magazine cites Drexler's Engines of Creation
A special issue (29 March 1999) of TIME Magazine titled "The Time 100: Scientists and Thinkers of the 20th Century," includes (on page 164, after describing the invention of the transistor) a brief article entitled "The Engines of Creation: Will Eric Drexler's nanotechnology do for the next century what silicon chips did for this?" The author speculates: "When the history of human civilization is rewritten a few centuries hence, the name Eric Drexler just might appear alongside those of Einstein and Freud. Drexler, 43, is the founding father of nanotechnology, the idea of using individual atoms and molecules to build practical machines." The article concludes: "Today nanotech researchers speak not of if but of when. Great leaps forward come from thinking outside the box. Drexler may be remembered as the man who saw how to build a whole new box."
The TIME article may be found on the Web at http://cgi.pathfinder.com:80/time/magazine/articles/0,3266,21853,00.html
The March/April 1999 issue of Technology Review featured a special report on nanotechnology "Nanotechnology: The Hope And The Hype". The three articles in this report highlight current progress in nanoscale science and technology but discount proposals for molecular manufacturing. Dr. Ralph Merkle has responded to this special report.
Prestigious government report cites breakthrough role of nanotechnology in manufacturing by the year 2020
"The National Academy Press (NAP) was created by the National Academy of Sciences to publish the reports issued by the Academy and by the National Academy of Engineering, the Institute of Medicine, and the National Research Council, all operating under the charter granted to the National Academy of Sciences by the U.S. Congress in 1863."
A book published last year by the NAP points to the role of molecular nanotechnology as an enabling technology and as a technological breakthrough needed to reach the goals set for manufacturing by the year 2020. A few exerpts from the book Visionary Manufacturing Challenges For 2020, produced by the Committee on Visionary Manufacturing Challenges, Board on Manufacturing and Engineering Design, Commission on Engineering and Technical Systems, and the National Research Council, NATIONAL ACADEMY PRESS Washington, D.C.1998.
The Science feature "Taking technology to the infinitesimal" opens with Chemistry Nobel laureate Richard Smalley saying "We're talking about the miniaturization of everything you can imagine. Eventually, we will be designing tiny devices so that every atom is there for a particular reason." However, the article mostly talks about the coming revolution in MEMS, or micro-electromechanical systems, which is an intermediate stage of miniaturization on the way towards nanotechnology. MEMS is related to current photolithographic technology used for making computer chips, and mates electronic circuits with sensors and mechanical actuators, but does not attempt atomically precise manufacturing, which requires working at a thousand-fold smaller scale. The article quotes experts as saying that in 10 to 15 years MEMS devices will be so common that people will be unaware of their presence in everything from computers to medical devices to intelligent flight control surfaces on airplanes.
The article concludes with a brief description of nanotechnology as a "still-nascent field" beyond MEMS. The "profound" applications of nanotechnology, such as "artificial spare parts for cells, new materials to make ultralight jumbo jets, machines the size of molecules" are described as "decades away, but theoretical and computational models confirm that the atomic manufacturing systems needed for the job do not violate physical laws." The author, John Yaukey, Gannett News Service, notes that Nature has been making atomically perfect machines in every living cell for billions of years.
A nanotechnology feature story on the ABCNEWS web site entitled "Science of the Very Small: Nanotech Visionaries Promise Wonders" quotes Ralph Merkle of Xerox Palo Alto, Jim von Ehr of Zyvex, Donald Noid of Oak Ridge National Laboratory, and Bill Spence, editor of NanoTechnology Magazine on how nanotechnology will permit building various devices to molecular or atomic specifications, and the effects upon materials, manufacturing technology, and medicine. On the other hand Charles Joslin, editor of the newsletter "Nanotech Alert," expressed strong skepticism that household molecular manufacturing would become a reality. The next few decades will tell the real story.
Follow media coverage of nanotechnology in Foresight Update
Media Watch columns. For in depth coverage on what the media is saying about nanotechnology, see the Media Watch column in most issues of Foresight Update. Media Watch columns from 1999:
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