Having just returned from ENTCON '94, it was clear that this is a topic which will occupy the minds of many developers and high-tech entrepreneurs. In the last two issues of M.E., articles from myself and other contributors covered some of the theoretical implications of nanotechnology of the future (bottom up, molecular synthesis and construction), and a glimpse into the current day developments in advanced micro machines and devices (fabricated with "traditional" top down, etched substrate construction).
Despite the theoretical aspects of what development paths may eventually become established, certain criteria can be viewed as a reference guide to suggest the most likely "chain of events" leading up to a nanotech development scenario here in the U.S. What is important to note here is that at this moment in time, unlike Japan (who already has established a ten year, $200 million nanotech development plan) there is no specific, centralized nanotech development organization or academic/industrial consortia to pursue this interest. What is occurring here in this country today, however, are various independent research groups, both academic/institutional, and corporate, delving into very narrow, or specific areas of investigation. The "missing ingredient" here may the temporary lack of a singular, centralized focal group which allows the "outsider" to view the entire spectrum of nanotech developments at a glance. This gap is currently being addressed, however, by at least one newly formed company, Nanothinc, in San Francisco, CA, which will be referred to the end of this article.
This, of course, is a crucial step in making the possible investment or support of nanotech development a more palatable business decision in the eyes of those willing to engage in a long term, leading edge development program. As in the case with many other technical developments in the past, it was usually a small handful of visionary scientists and developers who were often "far ahead of their time" who created what eventually became "mainstream" technologies with huge commercial benefits. In the realm of molecular synthesis and construction, however, the stakes could be potentially larger than any other singular development in history.
Grandiose as that may sound to the ears of the skeptic (and admittedly, there are those who view nanotech as "science fiction"), the facts are that even if only a small portion of nanotech related products should eventually emerge, such as nanoscale logic components (for ultra powerful, miniature computers), potential bio-medical applications, an entire realm of new engineered materials, and so on, the effect on various industries could be profound.
But of vastly greater implication is the concept of "nanofoundries" as manufacturing systems which could essentially fabricate, at the molecular level, virtually an unlimited variety of materials and devices on demand. A nanofoundry of the future would not consist of a large, complex "factory" as one might envision by today's standards, but rather be a small "box" that could literally sit on a desktop, but be capable of synthesizing whatever the designer has in mind, on the spot.
It is the eventual availability of ubiquitous molecular manufacturing systems to the general population that may cause the "industrial revolution" of the next century. What is important now is to be at the beginning edge of this realm of development, rather than simply follow along somewhere in the future. Unlike other major technology development programs, the actual costs and lab equipment required to establish a nanotech development lab can be surprisingly small. In fact, the major costs associated with such an effort would most likely be more in the realm of human costs (a collection of world class chemists and physicists, and computer experts would be the core of such a team), than in huge, expensive, equipment costs. We're not talking about building a super-conducting, super-collider accelerator, or launching a series of space shuttle flights here.
In fact, the actual lab equipment required could be very minimal indeed. An STM (scanning tunneling microscope) and/or an AFM (atomic force microscope) would of course be essential research tools. These are surprisingly small devices, however, and can easily sit on a desk or lab bench. Powerful computing capability is a must for complex molecular modeling and simulation, of course, and a certain range of chemistry equipment and supplies would be required. But again, this is not the stuff of a huge refinery, or a nuclear facility. This entire setup could easily fit into an ordinary office building. It would seem reasonable to assume that a focused effort could be initiated by a consortium of private developers, and perhaps federally financed programs, to pursue this area of interest.
So why isn't this being done already? Well, it is, just not in this country. Furthermore, lack of awareness even amongst the technical community is still probably the greatest impediment toward a more robust pursuit of applied nanotech development. In a current political environment where budget cutting and huge social programs seem to be the trend of the moment, it is difficult to find a sympathetic ear in Congress or the Senate for something as seemingly unconventional as exploration into the realms of nanoconstruction and molecular synthesis. After such recent "big science" fiascoes as the now de-commissioned super conductor-super collider accelerator, the Hubble telescope, and the recently launched $900 million Mars probe that was "lost" somewhere in the solar system, public sentiment for anything even remotely resembling a long term scientific development commitment is at an all time low, regardless of how promising the eventual results may be in the future.
The irony here is that even an ambitious, all out nanodevelopment project would be surprisingly small by comparison to the previously mentioned examples. But to expect the average public to even understand, let alone actually endorse the expenditure of tax dollars, on something as technically "unusual" and seemingly futuristic as nanotech is simply a risk that most politicians are absolutely unwilling to put their names on. In that light, it is most likely that the majority of development support here in the U.S., for the foreseeable future, will come from private and corporate sponsors.
Notwithstanding the state of affairs for actual development funding and political sentiments, the technical parameters for nanotech development could be manifest in several different directions depending on who is asked. But some general features as envisioned by those actually involved in this type of development, are consistent across the range of current researchers.
This is, in fact, the approach that the Japanese MITI research program is focused on, and may indeed yield the first real commercially viable results. In the other "camp", which is characterized as being mostly the American style of approach to creating molecular construction components and machines, is to develop "engineered" molecules constructed from scratch with carbon based diamondoid molecular "legos" that can be "snapped" together via a process referred to as piezochemistry. In this realm, even though the end results may be farther off into the future than the protein folding approach of today, the potential rewards are truly astonishing, since it would be in this realm that the tools of true molecular synthesis would be developed.
Just what types of devices would emerge from a theoretical, diamondoid structure based nanofoundry? For starters, an entire series of molecular mechanical components, such as gears, levers, ratchets, rollers and bearings, spring loaded actuators, i.e.; the "stuff" of a complete mechanical component system from which any type of molecular machine could constructed. With these types of construction components to work with, nano designers are envisioning such schemes as nanomechanical computers, somewhat like a molecular abacus, yielding a performance/volume ratio comparable to a Cray supercomputer occupying a volume of 1 cubic micron.
In fact, should this type of nanomechanical "tool system" become a de facto reality for "general purpose" nanofoundaries available to the entrepreneurial developer, there is likely to be no limit to the range of possible applications that could emerge. After all, when the first laser was successfully demonstrated at Bell Labs in 1956, how many of those early developers envisioned the extraordinary range of possible applications that the laser would eventually be utilized for? And as an analogy, that is only a tiny example compared to what "general purpose" nanofoundaries could eventually yield.
But how do we actually get from theory to applied development, and eventual application? The first step is to establish a mechanism for actually "picking up" and manipulating individual atoms and molecules for assembly purposes. This can be done now, either by utilizing an STM (scanning tunneling microscope) or an AFM (atomic force microscope), both devices having the ability to actually "handle" atoms and molecules, and to provide actual visual imagery of the atoms themselves.
However, even though these devices are essential research tools, they are far from being practical molecular manufacturing devices, since manipulating even a small number of atoms would be an excruciatingly time consuming process. Considering that the various complex molecular assembly tools envisioned by various theorists would consist of 3 to 4 million atoms each, the most obvious solution is to try to develop various "intermediate" molecular handling tools, themselves constructed out of fairly "simple" molecular devices.
Back to the realm of modified, protein like, structures, and also a class of self-assembling chemical components referred to as organometallic compounds, this may be the realm from which these first tools will be developed. Organometallic compounds are very interesting from a molecular structure point of view, since the structure of a molecular solid formed from such molecules can be radically altered by a change in the chemical substituent of one component. The structure can also be altered by changing the charge on one of the constituents in the compound.
Protein based molecular constructions have very useful properties, including chemically induced kinetic activity, which makes them highly suited as possible molecular "grabbers".
In fact, in the realm of bacteriophages, and protein based structures, a considerable variety of molecular scale motion translation devices could in fact be constructed as a system for handling molecular components and component groups. Therefore, given this criteria, a theoretical model of a six stage nanofoundry development program would most likely start with the development of a pseudo protein molecular system. This would provide the first stage of molecular handling devices that are themselves molecular components.
This circumstance would most likely lead to the development of more "complex" protein based molecular tool systems, in which an elaborate combination of molecular handling tasks could be accomplished as a molecular "manufacturing" sequence. This "second" stage of development is a crucial step, since it is at this juncture that the more ambitious task of true "mechanosynthesis" development and assembly begins.
As Dr. Eric Drexler himself states (author of Nanosystems, Engines of Creation, and founder of the Foresight Institute) "advanced mechanosynthesis will employ advanced nanomachines, but advanced nanomachines will themselves be products of advanced mechanosynthesis". In the previously mentioned molecular systems, synthesized protein structures are modified, or folded to produce the molecular shapes of interest, or self assembling organometallic compounds form complex shapes based on the electrostatic enforcement of combining organic compound "chunklets" and metallic lattice structures.
However, the ultimate goal is to use these molecular "tool" components as a method for constructing carbon based, diamondoid crystalline structure components. The reasoning here is that the diamondoid components have extremely robust fatigue life and durability characteristics, as well as excellent thermodynamic, stiffness, and structural properties. Furthermore, from a chemistry point of view, these structures lend themselves very well to yet another recently developed area of research referred to as piezochemistry, or pressure induced reaction states.
This provides a mechanism where the appropriate diamondoid molecular forms can be "snapped" together, almost literally like molecular "legos". This modality actually falls under the larger realm of mechanochemistry, which refers to processes in which mechanical motions control chemical reactions. Given this definition, one can draw a comparison between machine phase chemistry, and more traditional solution phase chemistry.
Therefore, the next development stage is to begin to construct the first stage of "simple" diamondoid components. This is perhaps the most daunting hurdle to successfully cross (no diamondoid molecular structure components have been constructed to date -- or at least, no published results have yet been offered to the public). It is at this stage that the first sets of "primitive" rods, cylinders, disks, and other basic geometric forms will be constructed.
However, having crossed this barrier, the successive stages of diamondoid development should accelerate rapidly, since constructing complete, diamondoid machines and machine systems is essentially the result of constructing ever more complex forms, such as bearings, gears, piston assemblies, and the like, and assembling them to construct complete machines.
It is at this crucial stage, the "third" diamondoid component stage, where complex tool and manipulation systems are assembled, and the ubiquitous realm of solution phase chemistry merges with this new domain of mechano phase chemistry. The reasoning here is that molecular and atomic "conveyer" systems, in which an entire array of molecular "grabbers", pick out the actual atoms and molecules that they are specifically designed to have an affinity for from a generic solution, or chemical "soup", can then have the selected atoms and molecules conveyed to the nanoassembly system. Once the selected atoms and molecules are delivered to the nanoassemblers, they are combined together, and "assembled" to form whatever material or structure might be desired.
Does the vision of Star Trek replicators seem simply too ridiculous to believe? The technology may never really evolve to the point of being able to "fabricate" a ham sandwich on demand, according to the molecular blueprint of the original sandwich, but certainly an almost unimaginable array of potential applications can arise from this.
In just one, very narrow realm, in medical applications alone, the implications for modifying the intracellular chemistry of almost any organ of the human body to cure diseases, prolong life, provide the potential for enhanced sensory and mental abilities, etc., are almost beyond comprehension. If even only a small fraction of the potential applications for "nanofoundry" device construction and molecular synthesis should come true in the future, the effects on society in general could be profound, and indeed, revolutionary.
Perhaps more importantly though, particularly for the entrepreneurial, technical developer, is the coming full circle back to a realm where the small company, or even the lone inventor, can conjure up devices and materials that have significance to the world at large (as opposed to only emerging from huge corporate or government financed development programs, as it tends to be today). In this realm, the nanofoundry of the near future could literally be a sort of "desktop" system, which would require nothing more than the raw atomic/molecular ingredients to "feed" the system, and the imagination of the developer using the system.
Copyright Charles Ostman, Midnight Engineering, May/June 1994