Building Blocks of Nanotechology
Buckyballs, Nanotubes, DNA, and Micromachines: Building Blocks of NanotechNanotechnology is a field that’s just being established, and although there are big plans for the smallest of technologies, right now, most of what nanotechnologists have accomplished falls into three categories: new materials—usually chemicals—made by assembling atoms in new ways; new tools to make those materials; and the beginnings of tiny molecular machines.
buckminsterfullerenes (almost always known as buckyballs or fullerenes), which are clumps of molecules that look like soccer balls. In 1984 Richard Smalley, Robert Curl, and Harold Kroto were investigating an amazing molecule consisting of 60 linked atoms of carbon. Smalley worked these atoms into shapes he called “fullerenes,” a name based on architect Buckminster Fuller’s “geodesic” domes of the 1930s and first suggested by Japan’s Eiji Osawa. Sumio Iijima, Smalley, and others found similar structures in the form of tubes, and found that fullerenes had unique chemical and electrical properties. Fullerenes became nanotech’s first major new material. But what to do with them? Engineers turned their attention to finding some practical use for these interesting molecules.
While engineers thought about practical uses for fullerenes another discovery in search of an application was being made. In 1981 Gerd Karl Binnig and Heinrich Rohrer invented the scanning tunneling microscope or STM, which has a tiny tip so sensitive that it can in effect “feel” the surface of a single atom. It then sends information about the surface to a computer that reconstructs an image of the atomic surface on a display screen. If that weren’t amazing enough, a little later, researchers discovered that the tip of the STM could actually move atoms around, and Donald Eigler and a team at IBM staged a dramatic demonstration of this new ability, spelling out "IBM". Researchers believed they had a tool, the atomic force microscope (AFM), that could build things atom-by-atom. But, like the discovery of fullerenes, it remained to be seen if anything useful could actually be built this way.
The development of tools such as AFMs coincided with the introduction of very powerful new computers and software that scientists could use to simulate and visualize chemical reactions or “build” virtual atoms and molecules. This was especially useful for scientists working with complex chemical molecules, particularly DNA. Researchers recognized that the actions of DNA resembled some of the things nanotechnologists were now calling for—the use of molecules to construct other molecules, the self-replication of molecules, and the use of molecule-size mechanical devices. Perhaps DNA (or its cousin, RNA) could be modified to create the first nanomachines?
With the appearance of protein-based chemistry and other techniques in the 1990s, researchers began looking both for practical uses for nanotechnology and new ways to make nano-molecules or micromachines. A different but related problem was that of making nanomolecules in large numbers. A single nanomachine or nanocircuit for example, would not be able to do enough work to make a difference in the real world—thousands or millions might be needed. Engineers needed ways to turn out their nanomachines in huge numbers, and so they began looking for a way to make a nano-scale machine or molecule that would assemble other nano-scale machines or molecules. K. Eric Drexler called it a “self assembler,” and scientists believe that it will be one of the keys to making certain kinds of nanotechnology useful and practical. To date, very few practical nanotechnologies and no self-assemblers have been used outside the laboratory.