|"Somebody needs to go out, put a flag in the ground, and say: 'Nanotechnology: This is where we're going to go.' We should have a serious national initiative in this area."|
|Dr. Richard E. Smalley
1996 Nobel Prize Chemistry
An inter-agency working group has recommended that the U.S. government double its funding of nano-scale research and development, to nearly half a billion dollars over the next three years. And in some of the most important public discussions of nanotechnology so far this year, a panel of expert witnesses testified before the U.S. House and Senate on the profound impacts nanotechnology will have, and offered their thoughts on how federal research and development efforts should be guided. The Foresight Institute has prepared a special briefing on these important developments.
"The impact of nanotechnology on health, wealth, and lives of people will be at least the equivalent of the combined influences of microelectronics, medical imaging, computer-aided engineering, and man-made polymers developed in this century," said Dr. Richard Smalley of Rice University's Center for Nanoscale Science and Technology, during his testimony before a House subcommittee. The Interagency Working Group on Nano Science, Engineering and Technology (IWGN) recommends the establishment of a national initiative as part of the Fiscal Year 2001 Budget. The report recommends doubling the current level of funding (now about $230 million) over three years.
In recent weeks, both the House and Senate held hearings to consider the recommendation. The hearings included extensive testimony from prominent researchers such as Richard E. Smalley and Ralph Merkle of Xerox PARC, federal research administrators from the NSF and Sandia National Laboratories, as well as from members of the U.S. Congress.
The witnesses were unanimous in their support for the IWGN proposal.
As Eugene Wong of the NSF told the committee, "Nanoscale science and technology represent a major opportunity for the nation. It is a strategic area for NSF and we seek your encouragement and support."
During his testimony, Smalley said, "I believe at the moment our weakness is the failure so far to identify nanotechnology for what it is: a tremendously promising new future which needs to have a flag," he said. "Somebody needs to go out, put a flag in the ground, and say: 'Nanotechnology: This is where we're going to go.' We should have a serious national initiative in this area."
Ralph Merkle put it very succinctly: "We know it's possible. We know it's valuable. We should do it."
Because of the importance of these developments, as well as their broad interest to the members of the Foresight community, we've prepared a special Foresight Briefing that contains expanded coverage of the IWGN recommendation for the proposed National Nanotechnology Initiative, and the U.S. House and Senate committee hearings.
In addition to the briefing, we've also posted a wide variety of other resources on this site, with links to additional material elsewhere on the Web.
Of course, we'll provide updates on these developments on the Web site and in future issues of Foresight Update.
Richard P. Terra is a Senior Associate of The Foresight Institute and the Institute for Molecular Manufacturing. He is also Editor of the quarterly Foresight Update newsletter.
|Foresight Update 37 - Table of Contents|
In April '99, approximately 150 people convened in Rome for the first European conference co-sponsored by EL.B.A. and the Foresight Institute (see http://fondazione-elba.org/efnano99.html).
EL.B.A. stands for "ELectronics Biotechnology Advanced", and it is an Italian research foundation focused on biomolecular electronics, which thus overlaps with the broader nanotechnology research arenas. Relatively few of the attendees appeared to have traveled from the USA. They mostly seemed to come from European countries, with a large contingent from Italy itself, many of which seemed associated with EL.B.A.
The talks spanned a wide range of different topics and types of research, not all of which appeared to be equally relevant for achieving the goal of constructing molecular machine systems. Given the interdisciplinary mix of the presentations, it would have helped if either the session chairs or the speakers themselves would have started with a one minute explanation of where in the scheme of things their work fits in, and how it relates to other work being performed. Very few speakers did that, which is also a problem at other nanotechnology conferences. And so, a somewhat incoherent impression was left behind by the scheduled sequence of talks, which jumped from topic to topic without the rationale and context that would have been desirable.
In this article, I will discuss a few talks that I found particularly interesting, but it is not at all meant to be a comprehensive review of the conference. Unfortunately, quite a number of invited key speakers were unable to attend. However, there were still plenty of interesting presentations left.
Jim Gimzewski (IBM, Zürich) reported that in the past, experiments using scanning probe microscopes (SPMs) to move single, individual atoms, such as Si, have not been very successful despite many attempts, largely because high energies are needed to rip the atoms out of the crystal lattices in which they reside. Actually applying that much energy with a SPM tends to lead more to destruction than to controllable rearrangement and construction. This is why his group focused on trying to move molecules that are relatively loosely bound to a surface, but still bound enough that they will not move on their own at room temperature. A porphyrin molecule was a particularly successful candidate, which looks like a square with four "legs".
The reason why this porphyrin has worked better than the molecules that other researchers have tried unsuccessfully is apparently due to the legs being somewhat flexible, but not floppy. This allows the legs to adjust to the spacing of the copper surface, to counteract the geometry mismatch, and to thus bind more strongly than would have been possible for a rigid molecule. These porphyrins can be moved around on the surface by pushing with the tip, allowing 2D patterning. However, controlled reactions with them and 3D stacking have not yet been accomplished. Using a different molecule system, a propeller-like decacyclene, instances of molecules spinning were observed, probably at MHz rotational frequencies, in locations where lattice mismatches allowed such motion. This reminds us that bearings on the molecular scale could work rather well.
Gimzewski is also involved in a different collaboration that utilizes micromachined cantilevers similar to the ones utilized in SPMs. Such cantilevers can be used as sensors, in which bending is detected by optical beam-deflection techniques. Bending is achieved by coating the cantilevers with metals, self-assembled monolayers, or polymers, such that the coating can interact with molecules in the gas phase, inducing a size change relative to the substrate. The resulting Nanomechanical Olfactory SEnsor (NOSE) has been used for fast and sensitive detection of everything from water vapor to perfumes. This application, while very useful, however presumably will not directly advance MNT, because "bulk" interactions are exploited.
Federico Capasso (Lucent, Bell Labs) claimed that we do not have to wait for nanotechnology to happen, because it is already used commercially as we speak. He obviously did not refer to molecular machine systems, but to semiconductor lasers, in which the thickness of crucial layers is measured in nanometers, which Capasso viewed as a one-dimensional form of nanotechnology. He presented the novel Quantum Cascade Laser (QCL), which differs in design from traditional laser diodes. The QCL emits at a wavelength of 5 micrometers, in the mid-infrared band. The light frequency can however be tuned by a Bragg deflection grating that sits on top of the active material, the spacing of which changes with temperature, thus selecting a different frequency.
It is unusual and impressive for lasers to be adjustable like this, and chemists doing spectroscopy have already shown great interest in the QCL. The important design detail is that the QCL is a repeating sandwich of layers in the conducting path, the thicknesses of which have been precisely engineered to have the correct electronic properties. In contrast to traditional laser diodes, where an electron falls into a hole once while emitting one photon, in the QCL, an electron travels up and down on the engineered potential energy surface, emitting several photons during its journey, which creates very efficient and intense laser light. Experimental devices have been built with 50 stages, and they tend to perform several orders of magnitude better than ordinary lasers. Capasso emphasized that the key to these achievements was a careful engineering of the quantum mechanical properties of the active material to obtain the desired relaxation times. Layers of precise thicknesses measured in nanometers were needed for this. Presumably this design knowledge will be of lasting value in a world of MNT, useful even when the actual manufacturing processes will have changed drastically.
Nadrian Seeman (New York University) has been doing highly relevant and interesting work for quite some time, trying to use DNA for fabricating molecular building blocks, to build both extended lattices and distinct molecular objects. He provided us with an update of recent work. In collaboration with Erik Winfree, Seeman has succeeded in making 2D regular carpets by letting two types of so-called double-crossover (DX) building blocks with distinct sequences hybridize together. Work on variations of this system continues, and Seeman showed a number of interesting images of these carpets, which were obtained with an SPM. Due to the versatile chemistry of DNA, a marker group can be attached to one of the DX molecules, which creates a 32nm spacing between the rows of markers in the carpet that is visible under the SPM. When four different types of DX building blocks were used, the spacing of the rows predictably increased to 64nm.
This is the first demonstrated, working system of building blocks that allows a versatile, "pre-programmed" assembly in patterns of considerable complexity. Rumors exist that work is under way to extend this system to 3D, which should be possible by minor modifications. Additionally, Seeman has worked on a simple DNA actuator (see Foresight Update #36, page 1, or on the web at http://www.foresight.org/Updates/Update36/Update36.1.html#BZDNA) that uses the transition of a special DNA sequence from the regular B-form to the unusual Z-form, a change that is reversibly induced by adding a cobalt salt into the solution. The actuator has two end states, one of which allows two groups to be brought into close proximity. However, currently this only represents one channel of control, and what really would be desirable is a dozen or more orthogonal signals for controlling simple nanomachines.
Charles Cantor (Sequenom, San Diego) confessed right at the beginning that his talk is not directly nanotechnology related. However, it demonstrated how powerful high-throughput molecular analysis methods have become, which could serve as a useful tool for some implementation paths to MNT. The Sequenom technology scans a chip containing a large array of DNA samples by a laser that causes the samples to get vaporized one after another, and a miniaturized mass spectrometer then determines the mass of the molecular species in the sample. This system has been honed such that it is now possible to obtain 20,000 mass spec measurements per day with extremely good accuracy. The vaporization technique is called Matrix Assisted Laser Desorption Ionization (MALDI). DNA is co-crystallized with hydroxy-picolinate, which evaporates when struck by a UV laser, carrying the DNA with it into the gas phase. One important improvement was to use ammonium for the counter ions for the DNA. Together, this allows high accuracy mass specs of DNAs up to 100 nucleotides to be obtained. DNA tends to be the most difficult molecule for this method because it is highly charged. The success with DNA means that other molecules including proteins are very easy to deal with in comparison.
Another crucial improvement was to lower the sample volume from microliters to nanoliters, which represents a large cost savings, essential because of the exotic chemicals needed, given that this technique is to be used for processing millions of samples. A key tool that enabled this scaling down was the advent of the Microdrop piezo-electric, micromachined pipettes that achieve picoliter accuracy. The current application at Sequenom is detection of point mutations, using short DNAs covalently bound to a single-crystalline silicon chip at very high density, then annealing complementary DNA primers that will get extended by one nucleotide if no mismatch occurs. The resulting length difference, measured by the mass spec, shows which samples contain the mutations.
Many other speakers presented interesting work. Some have attended earlier Foresight conferences, and some have not. At the end of this conference, a panel was held, consisting of Jim Gimzewski, Ralph Merkle (Xerox PARC), Claudio Nicolini (EL.B.A.), and Wolfgang Knoll (MPI, Germany). It was interesting to observe how the three Europeans on the panel teamed up, and emphasized that they are interested in obtaining funding from the European Community. For this purpose, they expressed the wish to distance themselves somewhat from the longer term vision as articulated by the Foresight Institute, and to instead focus narrowly on short term, fundable, experimental research on the nanoscale.
They are also proposing that more careful use of terminology is made. In particular, the term "nanotechnology" has come to mean so many different things that it would be better to call the current nanoscale experimental work "nanoscience". It is a welcome development if the scientific community is actively helping to disambiguate the terminology in such a manner. It was also agreed that the Europeans will hold their next nanoscience and technology conference, tentatively scheduled for September 2000.
Markus Krummenacker is a Foresight Senior Associate.
|Foresight Update 37 - Table of Contents|
Conference home page: http://www.foresight.org/Conferences/MNT7/
Register online: http://www.foresight.org/Conferences/MNT7/RegInfo.html#RegForms
For more information: tel. 650-917-1122; fax 650-917-1123
The purpose of this tutorial is to introduce fundamental areas of nanotechnology to newcomers and to strengthen the interdisciplinary knowledge base of seasoned researchers.
Powerful new concepts and capabilities such as atomic-scale imaging and manipulation, self-assembly, and biological structure/function relations together with increasingly powerful computational tools are rapidly converging from disparate research fields to enable a viable molecular nanotechnology. Those with science, engineering or software backgrounds are invited to participate either to begin new careers in nanotechnology, or to expand their expertise into new areas and capabilities.
Phillip Russell, North Carolina State University
Paul McEuen, University of California at Berkeley
Donald Brenner, North Carolina State University
BIO-NANOTECHNOLOGY: LESSONS FROM NATURE
David S. Goodsell, Scripps Research Institute
From Foresight Update 37, originally published 30 July 1999.
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