Written by K. Eric Drexler
The future of nanotechnology
The future of technology is in some ways easy to predict. Computers will become faster, materials will become stronger, and medicine will cure more diseases. Nanotechnology, which works on the nanometer scale of molecules and atoms, will be a large part of this future, enabling great improvements in all these technologies. Advanced nanotechnology will work with molecular precision, building a wide range of products that are impossible to make today.
When I first introduced a broad audience to the term "nanotechnology" in my 1986 book, Engines of Creation, I used it to refer to a vision first described by Richard Feynman in his classic 1959 talk, "Thereís Plenty of Room at the Bottom." This vision, (expanded upon in technical detail in my 1992 book Nanosystems: Molecular Machinery, Manufacturing and Computation), projects the development of productive nanosystems, in other words, nanoscale machinery able to build atomically precise products under digital control. Drawing inspiration from biology, this vision generalizes the nanomachinery of living systems and promises a broad set of productive capabilities with unprecedented power and commensurate opportunities and consequences.
Why focus on productive nanosystems and the large-scale molecular manufacturing processes that they will enable? Because these developments will extend the range of what human beings can manufacture, and through this will change the foundations of physical technology.
Every manufacturing method is a method for arranging atoms. Most methods arrange atoms crudely: even the finest commercial microchips are grossly irregular at the atomic scale, and much of today's nanotechnology faces the same limit. Chemistry and biology, by contrast, make molecules defined by particular arrangements of atoms -- always with the same numbers, kinds, and linkages. Chemists use clever methods to do this, but these methods donít scale up well. Biology, however, uses a different, more scalable method: cells contain productive nanosystems (ribosomes) that use digital data (from genes) to guide the assembly of molecular objects (proteins) that they serve as parts of molecular machines. Molecular manufacturing will likewise use stored data to guide construction work done by molecular machines, greatly extending abilities in nanotechnology.
The molecular-assembler concept
The basic idea of controlled molecular assembly is simple: where chemists mix molecules in solution, allowing them to wander and bump together at random, molecular assemblers will instead position molecules, bringing them together in a specific position, orientation, and sequence. Letting molecules bump at random leads to unwanted reactions -- a problem that grows worse as products get larger. By holding and positioning molecules, assemblers will control how the molecules react, building complex structures with atomically precise control.
Picture an industrial robot arm standing next to an unfinished workpiece. A conveyor belt supplies the arm with parts, each mounted on a handle. Step after step, the belt advances, the robot grips a fresh handle, plugs the attached part into the workpiece, then puts the empty handle back on the belt. Eventually, the workpiece is finished and another belt moves it away, shifting a new unfinished workpiece into place.
To picture a molecular assembler in a manufacturing system, imagine that all the parts are measured in nanometers, and that the transferred parts are just a few atoms, shifting from handle to workpiece through a chemical reaction at a specific site. An assembler will work as part of a larger system that prepares tools, puts them on the conveyor, and controls the programmable positioning mechanism. Their small moving parts will enable them to operate at high frequencies: because each motion traverses less than a millionth of a meter, each can be completed in less than a millionth of a second. This enables extremely high productivity.
Machines of this sort will be complex systems that are several technology generations away. Indeed, no one is even trying to directly build molecular assemblers today, because nanotechnology is still in its infancy. We can see a path to assemblers, just as the rocketry pioneers of the 1930s and 1940s could see a path to the Moon. But like those pioneers, we aren't ready to attempt the final goal. They knew they must first launch many satellites, just as we must first build many molecular machines. Some of the early machines may resemble the small, simple productive nanosystems that are used today in nature and in biotechnology.
Understanding advanced capabilities
We can catch a glimpse of future technologies because we sometimes can understand things that we can't yet build. Chemistry, biology, engineering and applied physics all provide useful perspectives.
Chemistry shows how structures can form when reactive molecules meet. By using molecular machinery to guide reactive molecules, similar structures can be built at larger scales. The products can be stronger, tougher and more capable than the delicate structures found in living cells.
Biology shows that molecular machines can exist, can be programmed with genetic data, and can build more molecular machines. Biology shows that the products of molecular machine systems can be as low-cost as potatoes. Molecular manufacturing will make a far wider range of products for similarly low costs.
Engineering shows that precisely made parts can be combined to make computers, motors, factories, and a host of useful gadgets. Applied physics, aided by computer modeling, shows that these sorts of devices can be built from atomically precise parts of nanometer scale. These glimpses of future technologies are enough to show some of the potential for molecular manufacturing.
Directions and applications
Molecular manufacturing will bring both great opportunities and great potential for abuse. Advanced systems could be used to build large, complex products cleanly, efficiently, and at low cost. Building with atomic precision, desktop-scale (and larger) manufacturing systems could produce the products like the following, with consequences for many global problems:
Faster, cheaper, cleaner production of superior products will also be disruptive. Costs, resource requirements and economic organization will be transformed. Advanced lethal and non-lethal weapons, deployed quickly and cheaply, could make the world a more dangerous place. The list of potential consequences is long, and as with all powerful technologies, the results will depend on the intent of the users.
In laboratories around the world, researchers are developing useful products and providing instruments, techniques and nanoscale components that will enable the development of future productive nanosystems.
We have seen steady advances in understanding and controlling atoms, molecules and atomically precise structures. Some instruments now enable researchers to observe and move individual atoms and molecules. The most widely known of these is the scanning tunneling microscope (STM), first developed by researchers at IBM Zurich's labs.
We have also seen progress in building novel structures along the lines proposed in my 1981 paper in the Proceedings of the National Academy of Sciences. This is the field of protein engineering which, together with DNA engineering, has demonstrated design and synthesis of atomically precise molecular objects like those that function as components of the molecular machinery, processing and electronics in biology.
Another area of rapid progress is computational modeling. Advances in hardware and software enable design and simulation-based testing of molecular devices, giving results with greater accuracy for structures on larger scales. This progress is crucial to the development of molecular systems engineering.
In considering these goals and accomplishments, it is important to distinguish long-term promise from present-day capabilities. Developing advanced productive nanosystems will require a multi-stage process in which today's laboratory capabilities are used to build molecular tools with broader capabilities. These tools, in turn, will be used in the next stage of development. Nanotechnology using productive nanosystems and their products will build on and extend the nanotechnologies of today, enabling a progressively broader range of applications.
The research that will support these developments is underway in laboratories in every industrial country. Unlike past revolutions in technology, the U.S., Europe and Asia are all making similar progress.
Sponsored by the U.S. Department of Energy.
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