Senate Interest in Nanotechnology:
New Technology for a Sustainable World
On June 26, 1992, the U.S. Senate Committee
on Commerce, Science, and Transportation's Subcommittee on Science, Technology,
and Space held a hearing on the topic of "New Technologies for a Sustainable
World." Dr. Eric Drexler, Chairman
of the Foresight Institute and Research Fellow
of the Institute for Molecular Manufacturing,
was invited to testify on molecular nanotechnology. The following is the
written testimony he submitted; a later issue will cover the oral
In 1959, the Nobel prizewinning physicist Richard
Feynman suggested that individual atoms and molecules could be positioned
and used as building blocks; experimental results now demonstrate that he
was correct. Molecule-by-molecule control can become the basis of a manufacturing
technology cleaner and more efficient than those known today. This molecular
nanotechnology will resemble processes in farms and forests, in which molecular
machines convert common raw materials--including surplus atmospheric carbon
dioxide--into useful products. It can be a basis for sustainable development,
raising the material standard of living while decreasing resource consumption
and environmental impact.
Molecular nanotechnology will have broad applications. It will provide a
general-purpose method for processing materials, molecule by molecule, much
as computers provide a general-purpose method for processing information,
bit by bit. It will by its nature be highly efficient in both materials
and energy use. Its products can include:
Clean, highly productive manufacturing systems
New molecular instruments for science and medicine
Extremely compact, energy-efficient computers
Stronger materials for lighter and more efficient vehicles
Inexpensive solar cells suitable for use in roofing and paving
Analysis and simulation based on existing scientific knowledge is enough
to show what molecular nanotechnology can do, but developing it will require
the construction of better molecular tools. The pace of development will
depend not on unpredictable breakthroughs, but on the magnitude and quality
of a focused development effort. The total development time is hard to predict,
but 15 years would not be surprising. Unlike some technology development
projects, in which few payoffs result until the end of the development cycle,
research in molecular nanotechnology will bring major scientific benefits
at an early date.
Molecular nanotechnology is worth pursuing both for its immediate scientific
benefits and for its later environmental benefits. Because there is reason
to think that it will become the basic manufacturing technology of the 21st
century--on grounds of cost, quality, efficiency, and cleanliness--its development
also raises issues of economic competitiveness. Japan's Ministry of International
Trade and Industry has recently committed some $185 million over ten years
to a nanotechnology effort.
The U.S. research community has not yet reached a conclusion regarding the
potential of this field because it has not yet addressed the basic scientific
issues. If we conduct idle debates on molecular nanotechnology while others
conduct active research, they will learn the answers to our questions. It
is time to assess the potential of molecular nanotechnology and to choose
a course of action. If its potential is even half as great as the evidence
now indicates, then medical, economic, and environmental concerns will favor
Mr. Chairman, I would like to thank you and the members of this subcommittee
for this opportunity to discuss a topic that I expect will one day become
a leading issue in these halls. The focus of this hearing--new technologies
for a sustainable world--is particularly appropriate for discussion of this
topic, because a concern with the consequences of future technologies for
the environment and for the human condition has for many years guided my
research, and has led to the results described here.
In the decade since I first described
molecular nanotechnology in the Proceedings of the National Academy
of Sciences, this field has progressed from general theoretical concepts
to early laboratory demonstrations and a growing body of detailed designs.
Five years ago, audiences questioned whether individual atoms could be placed
in precise patterns; today, I can answer that question not just with calculations,
but with a slide showing the letters "IBM" spelled using 35 xenon
The Foresight Institute, which I serve as Chairman, sponsors a series
of scientific conferences on molecular nanotechnology. The most recent,
held last autumn, was cosponsored by the Stanford University Department
of Materials Science and Engineering and the University of Tokyo Research
Center for Advanced Science and Technology; this meeting has stimulated
at least three laboratory research efforts directed toward a key milestone
on the path to molecular nanotechnology. Japan's Ministry of International
Trade and Industry recently committed some $185 million over the next ten
years to a nanotechnology research effort; development of molecular systems
is seen in Japan as fitting with the broad goal of developing environmentally-compatible
Momentum toward the development of molecular nanotechnology is building
around the world. The consequences for human life and for Earth's environment
will be enormous, and could be enormously positive. The balance of this
testimony begins by describing molecular nanotechnology from a biological
and ecological perspective and sketching some of its wide range of applications.
It then describes the relevant areas of research; the level of activity
in the U.S., Japan, and Europe; and some of the policy issues that its development
can be expected to raise. The closing section discusses how these concepts
can be evaluated before committing to any substantial effort that presumes
Molecular nanotechnology: a biological and
Industry today consumes fossil fuel and discharges carbon dioxide into the
atmosphere. Forests and farms, in contrast, produce useful products (including
fuels) while removing carbon dioxide from the atmosphere. Proposals for
reducing the concentration of greenhouse gases typically focus on modifying
existing industrial technologies to reduce emissions, and this is a sound
strategy. Yet it may be better to develop industrial technologies that,
like forests and farms, are carbon dioxide consumers.
Leaves are solar energy collectors employing molecular electronic devices:
chlorophyll molecules and photosynthetic reaction centers. These solar energy
collectors, like the other useful products of forests and farms, are built
by systems of molecular machinery such as ribosomes and metabolic enzymes.
A natural direction for technology, then, is to learn to apply systems of
molecular machinery to build useful products in industry. The example of
green plants indicates some of the results that can be expected from molecular
Low-cost production of solar collectors
Low-cost production of large structures (though stronger than wood)
No production or disposal of toxic chemicals
Absorption of atmospheric carbon dioxide
Compatibility with the natural world
Although no technology can, by itself, solve environmental problems, a technology
with these characteristics can be a great help. If a high standard of living
and reduced environmental impact can be achieved with relatively little
sacrifice, then any given amount of political and regulatory pressure should
yield greater results in reducing the impact of human activities on the
Taking the biological analogy as far as the preceding paragraphs have done
risks the misunderstanding that molecular nanotechnology will be a form
of biotechnology. The differences are large: Molecular nanotechnology will
use not ribosomes, but robotic assembly; not veins, but conveyor belts;
not muscles, but motors; not genes, but computers; not cells dividing, but
small factories making products--including additional factories. What molecular
nanotechnology shares with biology is the use of systems of molecular machinery
to guide molecular assembly with clean, rapid precision.
Another biological analogy seems appropriate: Aircraft and birds share some
basic principles of flight, and birds inspired the development of mechanical
flight. It would have been futile, however, to attempt to develop aircraft
by applying genetic engineering to birds, or by concentrating exclusively
on ornithological research. The Wright brothers studied birds, but they
then set off in a fresh direction. Molecular nanotechnology cannot be achieved
by tinkering with life, and its products will differ from biological organisms
as greatly as a jet aircraft differs from an eagle.
Range of applications
Molecular nanotechnologies will be based on molecular manufacturing, a fundamentally
new way to produce materials and devices from simple raw materials. By guiding
the assembly of molecules with precision, it will enable the construction
of products of unprecedented quality and performance. Because it will work
with the fundamental molecular building blocks of matter, it will be able
to make an extraordinarily wide range of products.
Computers provide an analogy. In the early decades of this century, many
specialized data processing machines were in use: these included the Hollerith
punched-card tabulators used in the census, Vannevar Bush's analogue machine
that solved differential equations for scientists, and adding machines used
in offices to speed accounting chores. Each of these slow, inefficient,
specialized machines has now been superseded by fast, efficient, general-purpose
computers; even pocket calculators contain computers. By treating data in
terms of fundamental building blocks--bits--general purpose computers can
perform essentially any desired operation on that data.
Today, manufacturing relies on many specialized machines for processing
materials: blast furnaces, lathes, and so forth. Molecular nanotechnology
will replace these slow, inefficient, specialized (and dirty) machines with
systems that are faster, more efficient, more flexible, and less polluting.
As with computers and bits, these systems will gain their flexibility by
working with fundamental building blocks. When desktop computers replaced
adding machines, they did more than speed addition. Molecular manufacturing
will likewise open new possibilities.
The applications of precise fabrication at the molecular level (mechanosynthesis)
are as broad as technology itself, because all of technology relies on manufacturing.
Molecular-scale components can be used to place the equivalent of a billion
modern computers in a desktop machine. Molecular-scale components will make
possible new medical and scientific instruments, including DNA readers able
to sequence genomes routinely. On a larger scale, production of better materials
will make possible lighter, more efficient vehicles, without sacrificing
structural strength: this will aid transportation technologies ranging from
spacecraft to automobiles. Lighter structures will consume less material
and energy. Because the lightest and strongest materials will be made from
carbon (in the form of graphite and diamond fibers), carbon dioxide can
become a raw material rather than a waste product.
Molecular manufacturing systems can be used to make more molecular manufacturing
systems, hence the capital cost of production can be low. An analysis of
inputs, outputs, and productivity suggests that the total cost of production
can be in the range familiar in agriculture and in the production of industrial
chemicals--tens of cents per pound. At this cost, many applications become
practical. For example, solar photovoltaic cells fabricated in the form
of tough sheets for roofing and paving could provide solar electric power
without consuming additional land.
With clean solar power, clean manufacturing processes, and light, efficient
products, it will be possible to provide a high material standard of living
with decreased impact on the natural world. This can contribute to the goal
of sustainable development.
Research directions and funding
These developments are not around the corner, but their feasibility can
be clearly foreseen, as can the nature of research programs able to implement
them. The essential goal is to construct molecular structures with the precision
already familiar in chemical synthesis and protein engineering, but on a
larger scale. Accordingly, properly focused research in chemical synthesis
and protein engineering (within the fields of molecular biology and biochemistry)
is important to the implementation of molecular nanotechnology, as is the
emerging field of molecular manipulation using proximal probe microscopes
such as the scanning tunneling and atomic force microscope.
Each of these areas is a classic small-science field, in which small teams
use inexpensive materials and equipment. The prospect of molecular nanotechnology
shows that small science can have big rewards.
I have not requested and do not anticipate a need for Federal funds to support
my own studies in this area, but the field as a whole could benefit from
vigorous support of appropriate computational simulation and laboratory
research. Since this work would be performed chiefly by existing researchers
with existing equipment, the need is more for a shift in direction than
for a growth in spending. Developments along the path to molecular nanotechnology
promise to yield early results in scientific instrumentation, making it
justifiable as a means of pursuing existing goals in chemistry and in biomedical
Progress toward molecular nanotechnology in the U.S. has been retarded chiefly
by cultural obstacles. Molecular nanotechnology will require the construction
of complex molecular machines, but chemistry and biochemistry are sciences,
and focus on the study of nature. To return to the example of aerospace
engineering, expecting molecular scientists to build molecular manufacturing
systems is somewhat like expecting ornithologists to build aircraft. Building
complex systems demands research that first defines goals and then works
backward to identify and implement the means, usually dividing the work
among many teams. Studying nature, in contrast, can be performed by small
research groups, each jealously guarding the independence and purity of
its research. The development of molecular nanotechnology can keep much
of the character of small science, but it will require the addition of a
systems engineering perspective and a willingness on the part of researchers
to choose objectives that contribute to known technological goals. Progress
will require that researchers build molecular parts that fit together to
build systems, but the necessary tradition of design and collaboration--fundamental
to engineering progress--is essentially absent in the molecular sciences
Furthering molecular nanotechnology might best be achieved by directing
federal agencies that perform or fund research in the molecular sciences
to support efforts aimed at the construction of molecular machine systems
and instruments that can precisely position molecules. The results of this
initiative could lead to cost savings in other programs. It has been proposed,
for example, that thousands of researchers be employed over many years at
great expense in order to read the human genome, yet the molecular machinery
found within a dividing cell reads (and copies) the entire genome in a matter
of hours. Scientific instruments based on relatively simple molecular machines
could read DNA with comparable speed and store the results in a computer
memory. The development of such instruments, once the necessary technology
base is in place, could hardly consume the efforts of thousands of researchers;
it would more likely require only a few cooperating laboratories. The result
would enable scientists to read and study many genomes.
Molecular machinery is a technology of basic importance and deserves to
be treated accordingly. This would be true even without the longer-term
goal of molecular manufacturing.
Assembled (a), cross sectional (b), and exploded (c) views of a design
for a planetary gear system containing 11 moving parts and 3,557 atoms.
Rotation of the inner shaft forces a rolling motion of the nine surrounding
gears, driving rotation of the larger shaft (to the right) at a lower speed.
A molecular machine component of this sort could not be made with existing
chemical techniques, but could be part of a mechanical system made using
molecular manufacturing. This design is the result of a collaboration between
Dr. K. Eric Drexler of the Institute
for Molecular Manufacturing and Dr.
Ralph Merkle of the Xerox Palo Alto Research Center, using molecular
simulation software developed by Molecular Simulations Inc.
Research in the U.S., Japan, and Europe
The U.S. has impressive strengths in areas of science and technology relevant
to molecular nanotechnology. It was at IBM's Almaden laboratory that Donald
Eigler's group spelled "IBM" using 35 xenon atoms. It was at William
DeGrado's laboratory at DuPont that scientists first designed and built
a new protein molecule, containing hundreds of precisely joined atoms. Nanotechnology
has become a buzzword, but is often used to describe incremental improvements
in existing semiconductor technologies; although of great value in their
own right, these are of surprisingly little relevance to molecular nanotechnology.
(Micromachine research, often confused with nanotechnology in the popular
press, is even less relevant.)
Progress toward molecular nanotechnology in Japan is harder to judge, owing
to distance and language barriers, but the Japanese commitment appears impressive.
In my visits to Japan, I have received a strikingly warm welcome. MITI organized
a symposium around my first visit, at which--despite my many talks in the
U.S.--I for the first time met other researchers who were studying molecular
machines not only to understand nature, but to build molecular machine systems.
On another visit, I spoke at the only scientific meeting on the construction
of molecular machine systems that I have attended but did not myself organize.
Japan's NHK television network aired a three-hour series this spring, titled
"Nanospace," that included interviews with me and material from
my work; nothing comparable has appeared on U.S. television.
While exploring a Japanese-language bookstore that I happened across in
Tokyo last spring, I found a table with eight books on micromachines and
molecular machines, all displayed face on. Half were paperbacks (including
conference proceedings containing a summary of a talk I had given in Tokyo
two years before), and half contained one or more graphics illustrating
molecular machine designs drawn from my work. One of these was a translation
of my first book on molecular nanotechnology, Engines
of Creation. I can with confidence state that no bookstore in the
U.S. contains a similar display, because no such set of books exists in
the English language.
MITI's commitment of $185 million is a sign of strong interest. In addition,
Japan's Science and Technology Agency, through the Exploratory Research
for Advanced Technology program, has sponsored a series of efforts in molecular
engineering, including the Aono Atomcraft Project, which aims to build semiconductor
devices with atom-by-atom control. I recently read that Texas Instruments
has established a laboratory with similar goals; the location they chose
is Tsukuba, north of Tokyo.
Researchers at Hitachi's Central Research Laboratory last year spelled "Peace
91 HCRL" by removing individual atoms from a surface. Researchers at
the Protein Engineering Research Institute in Osaka (no comparable institute
exists in the U.S.) have designed and built the largest protein molecules
of which I am aware. Nanotechnology has been a serious goal in Japan for
longer than it has in the U.S., and is seen as contributing to technologies
in greater harmony with the natural world.
I am less familiar with research in Europe, but key technologies (such as
the scanning tunneling microscope) have been developed there. Dr. Hiroyuki
Sasabe of the RIKEN Institute in Japan tells me that there are several research
consortia in Europe doing work on molecular systems, and that he knows of
no similar consortia in the U.S.
Molecular nanotechnology will raise numerous policy issues. In many areas,
years of consideration will be necessary before wise policies can be formulated.
This section provides only a brief, preliminary survey of a few issues of
Research in molecular nanotechnology will by its nature pose no special
risks so long as it remains unable to make large quantities of product.
In its early phases, it will most closely resemble a branch of laboratory
chemistry, and its chief product will be information. Later, when large
scale applications become possible, major regulatory issues will arise.
Further work will be necessary to identify these issues, but because molecular
manufacturing can be used to produce high-performance systems of many kinds,
these issues will surely include arms control.
Because the U.S. has no clear lead in this technology and because large-scale
commercial applications are still distant, international cooperation in
research may be desirable. Further, because potential long-term applications
include weapon systems, a failure to establish cooperative international
efforts could lead to dangerous outcomes. These considerations suggest the
desirability of a development program involving international cooperation
centering on shared global concerns with health and the environment. One
possible vehicle for this might be an expanded version of the existing Human
Frontier Science Program.
It seems that no special regulatory issues will arise for some time, but
this time should be used to gain an understanding of the issues that will
emerge as the technology matures. Cooperative development can provide a
basis for eventual international controls, for example, of the use of molecular
manufacturing in arms production.
Evaluating molecular nanotechnology
The U.S. scientific community has reached no consensus regarding the prospects
for molecular nanotechnology; indeed, these ideas have stirred heated controversy.
A recent OTA study could identify no published scientific arguments on the
other side (vague and unscientific objections have been common), but it
would be unwise for a decision maker to advocate a major commitment of resources
to molecular nanotechnology without further study and evaluation.
This autumn, the first quantitative, detailed, book-length analysis of molecular
manufacturing will be published (Nanosystems:
Molecular Machinery, Manufacturing, and Computation, Wiley Interscience).
This work lays out the fundamental principles of molecular machinery and
describes how molecular machines can collect, orient, process, and assemble
molecules with high efficiency and reliability. If there is a major error
or omission in this analysis of molecular manufacturing, it should be possible
for a critic to describe the difficulty in quantitative, scientific terms.
Experience shows, however, that the scientific community does not move swiftly
to evaluate interdisciplinary engineering proposals. No single discipline
sees it as a responsibility, and most scientists see the work as a distraction
from winning their next grant. If these concepts are to be evaluated soon,
and well enough to enable decision makers to choose with confidence, deliberate
action seems necessary. A natural choice would be to commission a study
of molecular manufacturing, setting the objective of evaluating its scientific
and technological feasibility by seeking specific, scientific criticisms
and responses from appropriate researchers.
A study of this sort could provide a basis for decisions and could stimulate
further debate and analysis that would provide a still better basis for
decisions. The Office of Technology Assessment may be an appropriate agency
to conduct this initial study.
Molecular nanotechnology promises a fundamental revolution in the way we
make things, and in what we can make. By bringing precise control to the
molecular level--resembling the control found in living organisms--it can
serve as a basis for manufacturing processes cleaner, more productive, and
more efficient than those known today. Like green plants, it can produce
inexpensive solar collectors and other useful products while removing carbon
dioxide from the atmosphere.
Because it will work with the basic building blocks of matter, its applications
are extraordinarily broad: they include improved materials and computers.
Early applications will include scientific and medical instruments.
Pure science has prepared the ground for molecular nanotechnology: it is
now time to build. Initial goals include the development of better techniques
for positioning molecules and for building molecular machines. Research
in chemistry, biochemistry, and proximal probe microscopy can all make substantial
contributions. Computational simulation has begun to show in detail what
can be built and how it will work. Design, simulation, and laboratory
research can all benefit from support targeted on genuinely relevant research.
Progress will depend largely on the willingness of molecular scientists
to solve problems that contribute to engineering objectives.
Research leading toward molecular nanotechnology is accelerating world wide.
Focused research is perhaps strongest in Japan. Although large-scale capabilities
(and the need for regulation) are still years away, it is not too early
to consider the consequences of success and to build the framework of international
cooperation that will be necessary in order to manage those consequences.
The preceding paragraphs assume that the analysis supporting the case for
molecular manufacturing is essentially correct, but there is as yet no consensus
on this. The evaluation of interdisciplinary proposals is slow in the absence
of a deliberate effort. It is time to make that deliberate effort, to evaluate
the evidence and set research priorities accordingly. If we merely wait
and see, we will accomplish more waiting than seeing. Economic competitiveness
and the health of the global environment may depend on timely action.
The term nanotechnology is here used to refer to an anticipated technology
giving thorough control of the structure of matter at the molecular level.
This involves molecular manufacturing, in which materials and products
are fabricated by the precise positioning of molecules in accord with explicit