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April 2001, Vol. 4
No. 4, pp 32–34, 36, 38.
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Focus: Nanotechnology
Feature Article
Nanotechnology

RICHARD H. SMITH

DNA building blocks and micromachines get down to work— still primarily as research tools.

Until about 10 years ago, people who used the term “nanotechnology” were considered technological Pollyannas or worse. Most serious scientists would not engage in public conversations about the topic without resorting to euphemisms.

As recently as 1996, many disparaged nanotechnology, particularly in the popular science press. Scientific American published an article that year titled “Waiting for Breakthroughs”, which compared nanotechnology research with pseudoscience as discussed by Richard Feynman in his 1974 essay “Cargo Cult Science”. Because Feynman is generally credited with originating the concept of nanotechnology, this was ironically unkind.

Billions of research dollars and several Nobel prizes later, it is unlikely that many would take such a negative position today. Now that President Clinton’s multiyear, multibillion-dollar National Nanotechnology Initiative has been funded, it seems that many research projects are labeled nano-something. Part of this phenomenon is “follow the leader”, and part is “chase the money”.

If a researcher can call her or his work nano-something, it is now considered more interesting—and more novel. And the possibility of funding increases.

Lately, nanotechnology has become a principal research interest across the globe. Its possibilities are explored in materials science, molecular electronics, and medicine. Businesses with significant funded nanotechnology programs include IBM, Intel, Renaissance Technologies (Canada), Zyvex, Lightyear Technologies, Argonide Nanometals Corp., Lucent Technologies, Nanogen, and Xerox Palo Alto Research Center.

Refereed journals with nanotechnology papers include Science, Nature, Analytical Chemistry, The Journal of Cell Biology, The Journal of Physical Chemistry, and Proceedings of the National Academy of Sciences.

Definitions and delineations
How did nanotechnology switch from unbecoming to obligatory so quickly?

Broadly speaking, we already have nanotechnology in the forms of monolayered chemical and engineering processes and nanosized MEMS (microelectromechanical systems) components. But these implementations do not convey the sort of nanotechnology that commands billions of investment dollars at the expense of other types of research.

Here is a working definition for the now-popular emerging megacapability: the intentional manufacture of large-scale objects whose discrete components are less than a few hundred nanometers wide (a nanometer is about 10 hydrogen atoms wide). By comparison, red blood cells are a few thousand nanometers in diameter.

The critical word in this definition is “intentional”. Nature has been manufacturing nanosized objects for billions of years (such as cells in plants and animals), but we do not call that technology. We want to achieve the capability of intentionally controlling matter at the molecular level. This would represent a breakthrough equivalent to breaking the genetic code.

Given a continuation of current trends, a truly potent nanotechnology will likely be realized within a decade or two. It could come in the form of exquisitely precise top-down procedures, such as moving molecules around with tiny robotic “hands”, or through a massively parallel bottom-up process, such as replicating cells.

Some investigators seek to create self-assembling mechanical systems—objects that exponentially copy themselves. These devices would bulk-manufacture the end products. Xerox is working on developing a new material that shapes and organizes itself—John Seely Brown of Xerox Palo Alto Research Center calls it “digital clay”. Others are examining DNA-based self-assembly, which is like acorns building oak trees but with humans designing what to build.

Either way, the hope for the long-range future is to create unimaginably tiny, yet communicating and/or programmable, molecular machines. These “nanobots” would build anything that could be specified in molecular detail—such as coatings, pharmaceuticals, and automobile parts. It is hoped that they will cure diseases and even reconstruct damaged DNA.

On the near horizon?
Dreams of future wonders aside, what is a realistic view of the current state of nanotechnology? Besides a few promising near-term product developments, nanotechnology today is mainly an area of research, not manufacture. So the most significant near-term results will be the dozens of projects, scores of laboratories, and thousands of trained scientists. But in addition to the infrastructure and training benefits,
some work looks as if it will be productive soon. See box 1 to read about nanotechnology applications that are realistic in the short term.

For example, teams at the Scripps Research Institute and Stanford University are investigating HK97, a harmless-to-humans virus that attacks bacteria. Emptied of its own genetic material, HK97—which is covered by 72 interlocking protein rings—could act as a nanocontainer or “molecular balloon” to carry drugs or chemicals to targeted locations in the body, even before buckyballs are ready for mass commercialization.

Also on the fairly short-term horizon is the use of nanoparticles coated with polyethylene glycol for pharmaceutical or gene delivery. Researchers at the University of Nottingham plan to use these particles to deliver conventional low molecular weight drugs, protein and polypeptide drugs, and DNA for oligonucleotide or gene therapy. (See “Advances in Drug Delivery Systems” for more information on nanotechnology and drug delivery.)

Initiatives
There are multimillion-dollar, government-sponsored, university-managed programs in at least 20 countries. Each offers funding to researchers who make the best proposals for nanotechnology research. Of course, the biggest project (or rather, collection of projects) is the National Nanotechnology Initiative. But even some states are getting into the field with ambitious and impressive ventures. California has formed the $100 million California NanoSystems Institute, which is designed to study nanotechnology from several different perspectives, including information technology and medical treatments. James Heath of the University of California at Los Angeles says that one of his team’s goals is to learn how to chemically synthesize quantum dots—“artificial atoms”—and assemble them into superlattices. The team is also studying biological electrical functions such as ion-channel switching and the nanocircuitry of biological systems, hoping one day to chemically synthesize a computer. New York and Pennsylvania also have nanotechnology initiatives. See box 2 to read about nanotechnology applications that are realistic in the medium term.

Given how long it will probably take to achieve results even in these limited areas, how can we forecast seemingly outrageous possibilities such as nanobots and one-size-fits-one pharmaceuticals? The answer lies in the fact that we are experiencing a phenomenal convergence of several technological forces, including the Internet, computing, and proteomics.

Nanotechnology applications that are speculative
These ideas are logically consistent but rely on unproven breakthroughs. They are improbable but are not disallowed by physics.

High-speed computing and postsilicon electronic devices
Communicating and/or programmable molecular machines.

Materials and manufacture
Controlled genetic erection of large-scale structures.

Artificial DNA as the programming language and the structural material.

Ability to manufacture virtually anything at practically no materials cost.

Medicine and pharmaceuticals
Nanobots that operate inside cells to cure diseases or reconstruct damaged DNA (i.e., nanobots that replace drugs).

Artificial immune systems.

No more surgery.

Environment and energy
Construction using air pollution as the source of raw materials.

Highways made of panels that collect solar energy and transport it to the power grid.

Great expectations
Because of the Internet, investigators are learning about advances in all technology fields more quickly than ever. Better search engines are helping to overcome challenges of disciplinary prejudice and ignorance. Computing speeds are increasing; we now expect 10-GHz desktop computers to do high-speed proteomic analysis. Proteomic analysis will soon allow us to consider controlled genetic self-assembly. Multigigabit per second bandwidth from anywhere to anywhere will make geography irrelevant. These forces are synergistic. Advances in one sphere increase the likelihood of significantly faster advances in the others. See box 3 to read about nanotechnology applications realistic in the long term.

That nanotechnology, even self-assembly with intentionality, is a serious field is no longer in doubt. But how to sort useful forecasts from unsupported conjecture remains a challenge. Are artificial immune systems worthy of discussion, or should we stick with what’s here and now? Should we fund only near-term deliverables and needed infrastructure, or challenge ourselves to keep investigating speculative but beneficial possibilities? The answer is easy: We should do both.

Suggested Web sites


Richard H. Smith is director of forecasts in science, technology, and engineering for Coates & Jarratt, Inc., in Washington, DC. He has served on government panels on military health care for the 21st century and on the implications of nanotechnology. Send your comments or questions regarding this article to mdd@acs.org or the Editorial Office by fax at 202-776-8166 or by post at 1155 16th Street, NW; Washington, DC 20036.

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