Nanotechnology is creating a growing sense of excitement because we see an opportunity of unprecedented magnitude looming on the horizon: the ability to arrange and rearrange 
molecular structures in most of the ways consistent with physical law. This will have a pervasive impact on how we manufacture almost everything -- what is manufacturing but a way to arrange atoms? If we can arrange atoms with greater precision, at lower cost, and with greater flexibility then almost all the familiar products in our world will be revolutionized. To name just three: we'll pack more computational power into a sugar cube than exists in the world today, we'll make inexpensive structural materials that are as light and strong as diamond (which will have a major impact on the aerospace industry), and we'll make surgical tools and instruments that are molecular in their size and precision, able to intervene directly at the fundamental level where most sickness and disease are caused.
Underlying the excitement is a very simple fact: while atoms can be arranged in almost infinite permutations, today we can make only an infinitesimal fraction of what is possible. Very roughly, if we can pack 100 atoms into a cubic nanometer, and each atom can be any of the
approximately 100 elements, then there are something like 100100 different ways we can arrange the atoms in just a single cubic nanometer. A cubic micron expands this to 100100000000000, while an object the size of you or me makes even this number seem vanishingly small. The goal that now seems possible: to take a healthy bite out of this enormous range of possibilities; to make most of the things that are possible, rather than an infinitesimally small fraction.
In 1959 Feynman said: "The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big." More recently, Smalley said "Most interesting structures that are at least substantial local minima on a potential energy surface can probably be made one way or another."
The breathtaking magnitude of this opportunity is attracting interest. Neal Lane, the Director of NSF, said: "The possibilities of nanotechnology are endless. Entirely new classes of incredibly strong, extremely light and environmentally benign materials could be created" and went on to discuss inexpensive superconductors and medical applications. NSF is backing up this rhetoric with grants. NASA has a computational molecular nanotechnology research group examining the ways in which this technology can be used to advance the exploration and human habitation of space. IBM is doing pathbreaking research to revolutionize computing. Storing one bit in a few atoms no longer seems outlandish, and molecular switches will someday replace the bulky devices made today using optical lithography.
As we move beyond the vision and start asking how we are going to do this and how long it will take, opinions begin to diverge. Should we make ever better scanning probe microscopes (SPM's)? These remarkable instruments have already demonstrated an ability to move atoms and molecules on a surface in a controlled way (often spelling out names of interest to the researchers or their sponsors), but have so far been confined to two dimensions. Stacking molecules one on top of another is the next obvious goal, which will no doubt be accomplished in the next few years. Could these versatile instruments go on to make molecular machines?
Or perhaps the design and modification of proteins and their self assembly will provide the key to progress? Living systems already use many molecular machines, such as molecular motors. Could we adapt them to our own uses, perhaps using them to power tiny pumps or open and close tiny valves?1
A computer generated image of a truncated octahedron experimentally synthesized from DNA by Nadrian Seeman.
There are many novel uses of existing biopolymers that could provide us with new tools. DNA, for example, is known primarily for its ability to encode information. But it can also produce structures as complex as a truncated octahedron2 and even provide power when it's chemical conformation changes in response to changes in its environment3.
The great diversity of proposals, ideas, and experimental capabilities makes it very difficult to predict exactly how we will proceed towards the more general goals of nanotechnology. Yet there are a few principles that seem both powerful enough and clear enough that they can provide some sort of framework for orienting ourselves. The first principle we consider is that of positional assembly.
molecular structures in most of the ways consistent with physical law. This will have a pervasive impact on how we manufacture almost everything -- what is manufacturing but a way to arrange atoms? If we can arrange atoms with greater precision, at lower cost, and with greater flexibility then almost all the familiar products in our world will be revolutionized. To name just three: we'll pack more computational power into a sugar cube than exists in the world today, we'll make inexpensive structural materials that are as light and strong as diamond (which will have a major impact on the aerospace industry), and we'll make surgical tools and instruments that are molecular in their size and precision, able to intervene directly at the fundamental level where most sickness and disease are caused.Underlying the excitement is a very simple fact: while atoms can be arranged in almost infinite permutations, today we can make only an infinitesimal fraction of what is possible. Very roughly, if we can pack 100 atoms into a cubic nanometer, and each atom can be any of the
approximately 100 elements, then there are something like 100100 different ways we can arrange the atoms in just a single cubic nanometer. A cubic micron expands this to 100100000000000, while an object the size of you or me makes even this number seem vanishingly small. The goal that now seems possible: to take a healthy bite out of this enormous range of possibilities; to make most of the things that are possible, rather than an infinitesimally small fraction.In 1959 Feynman said: "The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big." More recently, Smalley said "Most interesting structures that are at least substantial local minima on a potential energy surface can probably be made one way or another."
The breathtaking magnitude of this opportunity is attracting interest. Neal Lane, the Director of NSF, said: "The possibilities of nanotechnology are endless. Entirely new classes of incredibly strong, extremely light and environmentally benign materials could be created" and went on to discuss inexpensive superconductors and medical applications. NSF is backing up this rhetoric with grants. NASA has a computational molecular nanotechnology research group examining the ways in which this technology can be used to advance the exploration and human habitation of space. IBM is doing pathbreaking research to revolutionize computing. Storing one bit in a few atoms no longer seems outlandish, and molecular switches will someday replace the bulky devices made today using optical lithography.
As we move beyond the vision and start asking how we are going to do this and how long it will take, opinions begin to diverge. Should we make ever better scanning probe microscopes (SPM's)? These remarkable instruments have already demonstrated an ability to move atoms and molecules on a surface in a controlled way (often spelling out names of interest to the researchers or their sponsors), but have so far been confined to two dimensions. Stacking molecules one on top of another is the next obvious goal, which will no doubt be accomplished in the next few years. Could these versatile instruments go on to make molecular machines?
Or perhaps the design and modification of proteins and their self assembly will provide the key to progress? Living systems already use many molecular machines, such as molecular motors. Could we adapt them to our own uses, perhaps using them to power tiny pumps or open and close tiny valves?1
A computer generated image of a truncated octahedron experimentally synthesized from DNA by Nadrian Seeman.
There are many novel uses of existing biopolymers that could provide us with new tools. DNA, for example, is known primarily for its ability to encode information. But it can also produce structures as complex as a truncated octahedron2 and even provide power when it's chemical conformation changes in response to changes in its environment3.
The great diversity of proposals, ideas, and experimental capabilities makes it very difficult to predict exactly how we will proceed towards the more general goals of nanotechnology. Yet there are a few principles that seem both powerful enough and clear enough that they can provide some sort of framework for orienting ourselves. The first principle we consider is that of positional assembly.