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Nadrian C. Seeman, professor of chemistry at New York University, is the winner of the 1995 Feynman Prize in Nanotechnology. The award, sponsored by the Foresight Institute, is given biennially for the scientific work that most advances the development of molecular nanotechnology.
Molecular nanotechnology draws on cutting-edge advances in physics, chemistry, biology and computer science to build structures measured in nanometers, or billionths of a meter. (Five atoms of carbon would occupy a space about one nanometer wide. It would take a space a million times larger, filled with 5,000,000 carbon atoms, to make a dot as big as the period at the end of this sentence.)
The Feynman Prize is named in honor of Richard Feynman, the Nobel laureate in physics who died in 1988. Feynman, who won the Nobel for his work on quantum electrodynamics (QED), first suggested at a talk in Caltech in 1959, entitled "There's Plenty of Room at the Bottom," that nature could be manipulated at a nanometer scale: "The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom." (Feynman also won fame as the person who determined that the "O rings" were the cause of the Challenger space shuttle disaster in 1986, and who roundly criticized space shuttle safety policy.)
Dr. Seeman received the Feynman award for developing ways to construct three-dimensional objects, including cubes and more complex polyhedra, from synthetic DNA molecules. Natural DNA is a linear strand from which scientists had not previously been able to create complex structures.
Such structures could serve as building blocks for new and highly resilient materials made of DNA frameworks, to which other functional molecules could then be attached. The breakthrough toward that potential was first reported by Dr. Seeman in Nature in 1991. That paper announced the construction of a cube, the first 3-D DNA "stick figure".
Natural DNA, which carries genetic information, is an extremely long macromolecule composed of two nucleotide strands coiled around one another in a "spiral staircase" arrangement. The strands of the staircase are composed of alternating phosphate and deoxyribose units; the rungs are composed of the purine and pyrimidine bases adenine, guanine, cytosine and thymine (A, G, C and T). The order in which the bases are arranged carries the genetic information when the strands unwind and replicate. Because the bases come in pairs (A and T, G and C), single strands of DNA can only associate in specific ways. Discovery of these rules led to "Determining The Molecular Basis Of Genetics," which won a Nobel prize for James Watson, Francis Harry Compton Crick and Maurice Wilkins.
Scientists have learned to direct the association between DNA molecules. Those that Seeman uses are synthesized in a certain prescribed order, allowing for construction of branched molecules shaped in ways that he directs.
In biology, branched molecules are intermediates in the process of genetic recombination that modifies and mixes genetic information. "But in terms of material science," Seeman says, "they allow us to make something that is not just a long piece of spaghetti; they in fact allow us to make molecules that have specific branches, relatively close together on the scale of the stiffness of the molecule." The resulting molecules are expected to be highly resilient, should not come apart easily, and could have other molecules attached to them for the construction of new and promising materials.
Such "smart materials" are expected to lead to the construction of biochip computers and nanoscale robots in which DNA would direct the association of molecules in a way that transmits information. Seeman's goal is to have the "stick figures" come together to form larger arrays. These cage-shaped DNA crystals could then be used as frameworks for the assembly of other molecules into preestablished patterns. Thus, these DNA molecules would serve as the scaffolding through which molecular structure and behavior can be studied, and upon which new materials can be assembled.
It was this work that led to the presentation of the Feynman Prize, which carries a $10,000 cash award, to Dr. Seeman in mid-November, 1995 (see Editor's Note, "News In Science," for the reasons behind UniSci's coverage at this time). The prize was presented by Dr. K. Eric Drexler, founder and chairman of the Foresight Institute. In presenting the award, Dr. Drexler said, "Ned Seeman's work is particularly significant because it provides the first systematic way of designing and building large three-dimensional molecular objects."
DNA objects have great promise for industrial, medical and technological advances. Included are the ability to better study the molecules that cause illnesses such as viral disease and to develop new, extremely soluble materials for use in surgery, engineering and medical research, in addition to the creation of new and highly resilient materials built on DNA frameworks to which proteins or other functional molecules are attached.
Seeman has recently discovered how to attach strands of DNA to points projecting from other DNA double helices. In addition to this DNA branching technique, he has also created knots and catenanes with synthesized DNA chains. (Catenanes are linked-ring molecules. The word comes from the Latin word, catena, meaning chain.) Seeman's method lays the groundwork for the construction of complex devices on a nanometer scale.
Building crystals using a relatively simple and predictable method starting from branched DNA would revolutionize crystallography. "Its greatest significance," said Professor Peter Dervan at Caltech back in 1991, "is that this atomic lego set gives molecular engineering a bottoms-up approach to construction. Seeman has brilliantly utilized the chemical and biological methods of DNA synthesis, and then used the biochemical methods, or restriction enzymes, for characterizing nucleic acid segments to prove his structure. It's neat stuff."
One of the most promising of a group of "nanotechnologists" who manipulate matter molecule by molecule and, in some cases, atom by atom, Seeman is a nucleic acid physical chemist and crystallographer. Seeman's laboratory, in the department of chemistry at NYU, studies structural transitions in DNA molecules associated with genetic recombination, unusual nucleic acid structures, and single stranded nucleic acid topology, in addition to working on the nanotechnological projects for which he has been recognized. His research is supported by the National Institutes of Health and the Office of Naval Research.
In his acceptance speech, Seeman told of drawing inspiration from the convoluted perspective in the artworks of M.C. Escher, showed a photo of light fixtures created from human bones in an Italian monastery, and illustrated a flowchart invoking various dieties to depict the frustrations of attempting to create crystals in the laboratory.
In a flash of inspiration "while sitting in the campus pub one afternoon," Seeman recognized that six-arm DNA branched junctions could be used to create cubic lattices. He was inspired by the well-known Escher woodcut, "Depth," of a school of fish-like creatures arranged in parallel in three dimensions, "just like the molecules in a crystal."
Since that inspiration, Seeman and his colleagues have built complex geometric figures from DNA, he said. He is now working with an alternating tetrahedron form, a concept for which Buckminster Fuller received a patent. Seeman said he is hoping to use the architectural properties of DNA to direct the assembly of other such molecules.
All readers of this coverage will want to visit the Web pages of Dr. Seeman's laboratory, especially the home page. While there, be sure to look at the graphic by Ken Eward depicting a DNA truncated octahedron constructed in the lab.
Then, probably the best starting point for an online exploration of nanotechnology in general is the website maintained by Dr. Ralph C. Merkle of Xerox PARC (Palo Alto Research Center).
On that page is a lucid introduction to the field, followed by other links, including Feynman's prescient talk in 1959 and other Feynman pages, reports from the 4th Foresight Institute Conference, the Institute itself, a paper by Dr. Merkle on self-replicating systems, and a truly beautiful page in Cornell's SciTech magazine done by Kai Wu, an undergraduate student in physics and materials science.
At the bottom of the page, there's a fine example of a structured Internet search utilizing the latest and most powerful search engine, Digital Equipment Corporation's Alta Vista. Readers might want to click on it just to see what a search engine can do and how quickly it can do it, or use it as an example for creating their own structured searches.
News In Science
When the Feynman Prize was awarded to Dr. Nadrian Seeman in November, l995, it was publicized by both the Foresight Institute and New York University. Nevertheless, there was little media coverage.
The American Heritage Dictionary defines news as "information about hitherto unknown events and happenings." Because of the lack of media attention at the time of the award, the story of this award is unknown to most people and therefore constitutes news under that definition, news that UniSci feels is fully worthy of coverage at any time.
When UniSci queried Dr. Seeman about his work earlier this year, we asked him if anything new had happened since the award in November, 1995. (We were seeking a "news hook" on which to hang the story.) Dr. Seeman told us that news takes place in his field in a three-year time frame, not in the moment-by-moment time frame of current events. This set us to thinking about timeliness in all science news, which is different, of course, from the timeliness of breaking stories.
Our decision was to run this story now.
We also strengthened our opinion that dating science stories on our pages would be counterproductive. UniSci is not a refereed journal of record, nor does it see itself in competition with other pages or with other media for news "beats." It is our job to put information about research at American universities in perspective for a large and growing audience on the Internet. We thank Dr. Seeman for strengthening our resolve. And we solicit feedback from our readers about this issue.
Additionally, there is so much potential in the field of nanotechnology that no single press release or news story can begin to do it justice. For that reason, we have chosen to dedicate most of the current issue to this subject, and to include on our pages, for this coverage, links to other pages, a practice we have previously avoided. We'd like to hear from readers about this style of coverage; click on UniSci now to send us a message.
The implications of research in nanotechnology go far beyond the specific results even of such key work as that of Dr. Seeman. Extending the concept enunciated by Richard Feynman in l959, of "maneuvering things atom by atom," nanotechnology can be expected to help us create virtually any structure allowed by the laws of physics and chemistry, putting atoms exactly where we want them and, at the same time, holding manufacturing costs to not much more than the costs of material and of energy.
This ability could lead to the creation of molecular-size robots that can be sent where we want them, to do what we want them to do, such as make repairs within a living body. And to nanoscale computers, passing information, not through the flow of billions of electrons, but through the change of shape or position of single molecules.
And there is the possibility of the creation of systems that can replicate themselves, just as natural DNA does. Such systems would have the power of reproduction, which would lead to vanishingly low manufacturing costs, if to nothing else. The concept of machines making machines just like themselves, so often dealt with in science fiction, would move into the realm of scientific fact. The philosophical implications are, of course, enormous.
In spite of this vast promise, Dr. Seeman's description of his work is modest: "Nanotechnology is a very fancy buzzword for the chemistry of the next century. To a certain extent, we're going to emulate the way things are done in cells." - Don Radler, Editor
March 3, 1996
I just have one small complaint about your coverage of the 1995 Feynman Prize in Nanotechnology. I do think that you should at least mention Rosalind Franklin's name when discussing the determination of the three-dimensional (3-D) structure of DNA.
The writer has been careful enough to include Wilkins' name alongside Watson and Crick. I'm sure that you're more than aware of the treatment of Franklin then and her subsequent portrayal in Watson's "The Double Helix". Of course, her name was not included in the award of the Nobel Prize in 1962. She was dead by this time. Some argue that this gave the Nobel Prize Committee the excuse not to recognise Franklin's contribution in the same way. In fact, I wasn't alive then and so don't really know what did and did not happen.
Anyway, there's no reason in 1996 to ignore her key contribution in actually obtaining the X-ray diffraction data from which Watson and Crick could propose a model for the 3-D structure.
Ed. Note: The writer may well be correct in his assessment that Rosalind Franklin's name belongs alongside that of Maurice Wilkins, although her death might have proved a convenience to the Nobel Prize award committee.
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