Small Wonders
The National Science Foundation Promotes Nanotechnology.
"The small has become as limitless as the large," declared National Science Foundation (NSF) Director Rita Colwell in her keynote kickoff to the NSF's Small Wonders: Exploring the Vast Potential of Nanoscience conference held in Washington, D.C., this week. This very upbeat conference is in marked contrast to the skepticism expressed only a decade ago about the prospects of engineering devices at the scale of nanometers (one-billionth of a meter–just slightly larger than many atoms). To give some idea of the scale, Colwell suggested that if the width of a penny represented one nanometer, a foot-long ruler would have to be represented by the distance between Richmond, Virginia, and Miami, Florida.
Colwell also sounded themes that later speakers would echo, particularly the importance of biological models to future nanotechnological developments. "Life itself is nanotechnology that works," she declared. She also maintained that the benefits of nanotechnology are "not going to materialize in some far-off future, but today."
Richard Smalley also delivered a very upbeat speech, "Nanotechnology: The Wet Side, The Dry Side, and the Wet/Dry Frontier." Smalley, who now heads the Center for Biological and Environmental Nanotechnology at Rice University, won the Nobel Prize in chemistry in 1996 for his discovery/creation of complex carbon molecules called buckminsterfullerenes and the fullerene family of molecules.
Smalley focused on the conceptual division at the heart of a lot of nanotechnological research. Wet nanotechnology is almost indistinguishable from biotechnology, e.g. creating novel diagnostics and drugs. Dry nanotechnology is generally aimed at electronic and mechanical properties of metals and ceramics, e.g. creating molecular-scale computers. Smalley was not bashful about the promise he believes nanotechnology holds for humanity: "It holds the answer, to the extent there is one, to our most pressing material needs including energy, health, communications, transportation, food, and water."
Many of these goals will be accomplished by combining organic (wet) nanotechnology with inorganic/electronic (dry) nanotechnology. Nature is superb at self-assembly and repair but lacks efficient electrical and thermal conduction properties and materials with great strength, toughness, and ability to resist high temperatures. "Life cannot conduct electricity the same way copper wires can," noted Smalley. "You cannot build a radio using cells nor supply cities with electricity by tying a bunch of electric eels together."
Smalley believes that the future of nanotechnology lies in finding ways to combine the "finesse" and "molecular perfection" of wet nanotech with the toughness and resilience of dry nanotech. "We are nature's way of developing the dry side of nanotechnology," he said.
Smalley highlighted the importance of carbon nanotubes ("buckytubes")–long hollow carbon fullerene molecules that are just a few nanometers across, about the same size as DNA strands. These molecules make the strongest fiber that will ever be, said Smalley. They have the electrical conductivity of copper or silicon and are 50 percent more efficient in thermal conductivity than diamond, which is the most efficient thermal material in nature. Furthermore, buckytubes are made with carbon, so their chemistry is already well understood by researchers and compatible with natural molecules. "Carbon nanotubes on the dry side play a role similar to DNA on the wet side," Smalley noted.
In the near term, Smalley predicts that supersharp flat-screen TVs based on carbon nanotube technology will be available in five to 10 years. Eventually, electronic nanotechnology may succeed in squeezing trillions of circuits onto computer chips–compared to the approximately100 million possible today.
Smalley addressed a theme that many subsequent speakers also took up: the tremendous possibilities that combining wet and dry nanotech offer for ameliorating and curing diseases. Smalley pointed to anti-cancer compound Zevalin, which has been designed using nanotechnological principles to deliver tumor-killing radioactive yttrium by attaching it to an antibody. Zevalin has already been approved by the Food and Drug Administration. "Most diseases are molecular diseases which will have cures only on the nanometer scale," concluded Smalley. Karen Wooley, a young researcher from Washington University in St. Louis, further highlighted the medical advances that nanotechnological research is already assisting, including drugs that help clear the body of excess cholesterol.
Herb Goronkin of Motorola explained that his company sees "the end of silicon electronics and no end to rising costs for silicon fabrication." Right now it costs around $2.5 billion to build a new computer chip factory and the trend lines suggest that in 10 years it will cost as much as $20 billion to build a state of the art facility. Molecular electronics may offer a way out. However, Goronkin does not believe that a commercialized terabit molecular circuit chip will be available until sometime between 2010 and 2020.
Don Eigler, the researcher at IBM who first understood that scanning tunneling microscopes (STMs) "invented as a set of eyes could also be used as a set of hands," also spoke. STMs trail a very fine point just above a surface to be scanned. High enough above the surface it will outline the atoms located there. A little bit closer to the surface and an STM can move atoms on the surface from one place to another. Eigler famously did this by arranging xenon atoms to form the letters IBM in 1989. Eigler captured the wonder of nanotech for the conference audience by using a remote computer video hookup to an STM at IBM's Almaden Laboratory in San Jose, California, to show how the devices can move a single carbon monoxide atom on a surface.
Angela Belcher, a professor at the University of Texas in Austin, wowed conferees with her talk on "Using Nature's Tools to Synthesize Nanoelectronic Materials." "Nanotechnology offers things that nature hasn't had a chance to work with before," said Belcher. She pointed to the lessons that nanotechnologists can learn from nature. For example, an abalone shell is 98 percent calcium carbonate, in other words, chalk. But as an abalone shell it is 3,000 times stronger than chalk. Belcher's research has really combined wet and dry by using a Darwinian process to force viruses to grow into sheets of semiconducting nanoparticles of zinc sulfide. Maybe one day we'll grow our own computers.
"Our vision is to hold infinity in the palms of our hands," declared Rita Colwell, paraphrasing the poet William Blake. Nanotech researchers are clearly getting ever closer to that goal.
