Nanotechnology: Molecular Manufacturing
Defining
Nanotechnology
Many
well-respected scientists have called it "science
fiction," "crazy," "too far out" to be given serious
consideration. The U.S. 2000 budget allocates $227
million to it, and the following agencies are participating
in an initiative to develop it: National Science Foundation;
Departments of Defense, Energy, and Commerce; NASA;
National Institute of Health. What is "it" that polarizes
skeptics and supporters?
The potential is staggering. Imagine the ability to build your food supply in a box-sized factory, assembling lunch molecule by molecule. Or the creation of a robot so tiny it could be sent into the human blood stream to "fix" diseases like cancer. Or the ability to translate electronic data into atomic arrangements on a special medium, so that a single square centimeter of the medium could contain 10 gigabytes of data. These are the types of projects that nanotechnology's supporters believe will become doable.
The
term "nanotechnology" was first coined by Eric Drexler
in 1981, while a graduate student at MIT. Nano- is
the prefix for one billionth (10-9); a
nanometer is a billionth of a meter, a millionth of
a millimeter. A nanometer is about three to five atoms
wide. The idea behind nanotechnology-- manipulating
atoms to build things-- was actually first proposed
by Noble-prize winning physicist Richard Feynman in
1959.
Nanotechnology is also called "molecular manufacturing"-- manufacturing products by moving atoms and molecules into desired arrangements. The basic concept says that goods could be manufactured in a "black box" with an assembler that arranges the individual atoms and molecules of the raw materials, lining them up until the desired product results. Clean, cheap production that could produce the tiniest ever computer processors, or food for the entire planet.
Traditional
Manufacturing vs. Molecular Manufacturing
Since
it's pretty hard to visualize nanotechnology, let's
start by understanding how it differs from today's
manufacturing processes. Think of a modern factory,
say a furniture factory that makes chairs. The factory
has a warehouse for raw materials: wood, fabric, stuffing
material, paint, varnish, hardware. The production
line workers take big planks of wood and cut them
down to the desired size to assemble into the chair
frame. Workers at another production line cut the
fabric and stuffing in order to upholster the frame.
If you were to bring the finished chair into a chemistry lab, you could analyze the molecular structure of the raw materials that compose the chair. The properties of any given object are a function of how its atoms and molecules are arranged. Instead of starting in a factory with masses of raw materials and cutting them down to produce a chair, nanotechnology starts in a lab-style factory with the atoms and molecules that will be inside the finished chair. The atoms are positioned into molecules, which are positioned into materials that form the chair--from its basic elements upward.
Molecular manufacturing is based on a model used in nature, for example by enzymes, hormones, and DNA. Let's look at one of nature's molecular manufacturing factories: photosynthesis. A plant takes molecules of raw materials--light, water, and carbon dioxide--rearranges them, and creates energy in the form of sugars. If you are not familiar with photosynthesis at all, do the activity Biology Gateways: An Overview of Photosynthesis. Then use the activity Biology Gateways: Light-Dependent Reactions in Photosynthesis to see how a plant rearranges molecules in two different "production lines" in order to create sugars and oxygen.
What's
Holding Us Back?
Photosynthesis is actually complex compared to what
nanotechnology is proposing. It will just take scientists
many years to figure out how to get every atom in
the right place and how to keep it there--something
that plants do naturally. How many years will it take?
Drexler predicts 15 as his standard answer.
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Buckyballs in Support
of Nanotechnology Buckyballs have many interesting properties,which scientists are still investigating. Among these properties are new forms of electrical conduction, new semiconductor behavior, and possible new ways to manipulate radiotherapy agents. Richard Smalley, Robert Curl Jr., and Harold Kroto won the 1996 Nobel Prize for Chemistry in recognition of their discovery of fullerenes. Read more about buckyballs at: A New Chemistry for Carbon. |
Scientists still need to learn how to control a number of processes before nanotechnology becomes feasible outside of the laboratory:
- The
manufacturing process must somehow be able to
maneuver individual atoms and molecules so that
they stay in a certain position. This positional
assembly method will probably require molecular
robots that can move the molecules around.
- Production costs must be reduced to commercially-acceptable levels by having molecular manufacturing systems not only build products, but construct other molecular manufacturing systems as well. Such a system is called a self-replicating system, and it works much like a piece of DNA building proteins. (If you are not familiar with how DNA replicates proteins, see the activity Biology Gateways: Protein Synthesis.)
Products
and By-Products
Suppose that scientists succeed in bringing molecular
manufacturing into the mainstream. Here are some of
the possible benefits:
- the creation of new materials (see the Buckyball side bar)
- miniaturization: the current process of building ever-smaller computer chips will reach its limits within a decade or so. Nanotechnology will enable production of chips that are significantly smaller, allowing more computing power to fit in. "Basically a supercomputer behind every pixel on your screen," Drexler explained in an interview to Red Herring magazine.
- atomic precision: engineers could build elaborate structures on a scale of up to 100 nanometers for tasks like storing information, switching electrical signals, converting sunlight to electricity, and transporting electricity long distances
- clean: the pollution associated with traditional forms of manufacturing would disappear
- doesn't deplete natural resources: if you don't need stores of raw materials, then you don't need to chop down trees or extract oil for manufacturing
- non-labor intensive: once the molecular manufacturing process is in place, you don't need a factory full of people to make it run
Yet nanotechnology may not be the answer for manufacturing of every product. It may well remain easier to build a chair from a plank of wood than to construct it atom by atom.
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