NANOTECHNOLOGY: THE NEXT REVOLUTION

at some symbiotic complexity threshold point, the "essence"
of sentience begins

No, this is not science fiction. As of this writing, there are teams of researchers here and abroad who are very specifically engaged in various forms of nanotechnology related development projects. Although the efforts in the U.S. are still somewhat scattered amongst a plethora of academic, and in some cases, corporate supported laboratories, Japan has already initiated a $200 million national nanotechnology development program.

I must reiterate at this point that this is not science fiction, nor is simply making yet smaller computers the target goal of nanotechnology utilized as a manufacturing process. As fundamental, and far reaching as the major milestones of human history such as the iron age, the bronze age, and in more recent times, the industrial age, and the current information age, the era of the nanotechnology age will perhaps be the most profound.

How does society deal with such issues, for instance, as molecular scale machines that can perform intracellular corrective chemistry in the human body, as a life extension process? Can, or should, everyone have unlimited access to such bioengineering modifications on demand? Will cybernetic enhancements, such as sensory and neural modifications be restricted to perhaps only specially authorized individuals in military or other specifically sanctioned professions? These are not easily answerable questions, but the ability to provide the technology to make such situations possible is soon to be at hand.

And perhaps, from an entirely different, but no less fundamental perspective, is the concept of an entirely new industrial and economic system, in which the coin of the realm is not measured by the possession of currency or physical property, but rather in nanotech "access credits".

In other words, in a domain where virtually any object or substance is available via ubiquitous "nano foundries" that can simply provide content on demand, it is not the physical object that has value, but rather the software, the assembly instruction sets that control the nanofoundries, that has value. Wealth, and the socio-economic power that it implies in this new paradigm, is measured by the range, and perhaps complexity, of the software types that can be applied to the nanofoundries of the future.

The nanofoundries themselves will no doubt be created in a variety of sizes and capacities to accommodate a range of fabrication capabilities, and indeed the generic "molecular soup" that provides the raw source material from which the nanofoundries construct the objects they are instructed to assemble may be made available at differing levels of molecular variety and complexity.

And, if this wasn't enough to consider, there is yet another entirely different realm of nanotechnology which is already well under way, and is rapidly accelerating into a new domain of "uncharted" technical and socio-economic territory. This is the realm of self-assembling materials, self modifying molecular structural systems, and even object oriented organelle components which can be "reassembled" into new, artificial organisms. Consider, for instance, a new class of materials, as in ubiquitous "nanites" that can be stimulated by chemical, photonic, or even electrically induced event cues to form into functional macro-objects. The newly formed macro-object, which could even have organism-like properties, would perform a task or range of tasks, and then be "instructed" to dissolve back to its original status as a cloud of individual molecular scale nanites, until another event cue stimulus causes the nanites to reform into perhaps another type of macro-object.

Sound far fetched? That depends entirely on who is asked. Amongst a number of physicists and chemists who are currently engaged in the realm of self assembling materials and molecular matrices, such terms as "utility fog", nanoputty, and nano-leggos are actually used in everyday discussions.

Indeed, in my own realm of work that I have been involved with along these lines, I attempted to formulate an outline, or functional descriptor profile, that would describe how such interactive nano-components would perform in this domain, up to and including organelle types that would have the ability to achieve sentience as an "assembled" organism of a given total size and complexity. An abbreviated form of this outline is included here.

The basic premise here is to present some possible conceptual models of various nano components, and what their properties or interactions would consist of. Some behavioral characteristics and properties that might be established are as follows:

the ability to create entirely new types of molecular scale computing devices that are not possible with top-down manufacturing processes...

In the realm of medical or bio-molecular subcomponent nano device applications, a variety of potential modalities are being considered. This can range from quasi-viral components that can target specific cell types and perform intra-cellular corrective chemistry functions, to "nanobot" machine devices which patrol the blood stream in search of intrusive microbes, and/or other types of stationary or mobile antigen triggered response devices, to morphable organelle components, as in the example of a bio-molecular "utility fog" system which could be triggered into responding to a range of chemical signature signals to morph into a "temporary" organism type.

What is perhaps most important to stress here, as stated earlier in this article, is that nanotechnology is a concept, and not a "singular" science. Therefore, when asked how far into the future is nanotechnology as an applications development technology, again it depends on who is asked, and what aspect of application is involved.

For instance, Dr. Drexler, who's primary focus is to develop molecular scale machine components fabricated from diamondoid which can then be assembled into machine systems that would in turn perform molecular assembly tasks, including object replication, sees this particular development as being a decade or more into the future.

On the other hand, protein machines constructed with molecular pseudo-protein components are being investigated now. Rotaxanes, "formed" DNA segments, and other molecular structures are currently being explored as possible logical devices for molecular computing components. Proteins, peptides, and other bio-molecular structures are now being applied to microscale implantable devices via a new photo-reagent "tethering" process, to provide biocompatable molecular surfaces, as a commercially available process. A laser driven "optical tweezer" process is currently being utilized to mechanically manipulate and reconstruct molecular structures in living cells to create new organisms.

Today, an atomic force microscope, or AFM, can be used not only to view molecular and atomic scale features, but to actually "pick up" and manipulate individual atoms and molecules as a mechanical process. Molecular "fibers" of polyacrylimide gel materials are currently being investigated for their biokinetic properties, as well as bacteriophage molecular constructions that can behave as "nanomotor" components. But this is only a very brief sample of current examples.

In fact, the range of nanoscale fabrication, mechano synthesis chemistry, and molecular construction related processes already being utilized, or in experimental applications, is very extensive, and could not possibly be covered in this article. No attempt can be made here to delve into such an extensive subject, except to explain the general concept, and point out that this is current, applied technology.

It is not a matter of if, or merely an academic debate as to "when" various aspects of nanotech are fully realized, but rather a question of how it will affect not just the seemingly distant or obscure realms of experimental science, but fundamentally affect life as we understand it to be today. Some may debate, and perhaps rightfully so, whether or not the general public will ever be even capable of fully understanding, or appreciating this rapidly emerging technical domain, but it is my personal belief that such considerations are a moot point. Whether the "nanotech revolution" is spawned here, or from other countries abroad, is irrelevant. What is relevant is that it will, and in fact, already has begun.

Speculation over the potential implications of micromechanical, and future nanotechnology developments can be tantalizing, to say the least. But what is actually available today, or is about to become available in the near future (one to two years from now). To answer this question, it is important to not merely focus on any specific device or particular "machine", but rather to view the industry as a whole, with particular focus on fabrication processes and materials development. As is the case with many other fundamental technology developments in the past, it is the symbiosis of many seemingly "unrelated" technologies that converge to create an entirely new arena of development. Perhaps never before in history has such a diverse range of technologies and scientific disciplines converged to establish this type of fundamental leap in applied technology.

Specifically in the case of micro-machined components, feature sizes of .1 microns are now considered within the realm of manufacturing feasibility. This has resulted from the past 20+ years of aggressive development for mass fabrication techniques applied to the manufacture of integrated circuits for the computer industry. Since the same micro lithography techniques used to etch transistor and conductor sites on standard silicon wafers can be directly applied to creating micromachine components, the industry as a whole is already "tooled up" to start fabrication of micromechanical "chips". In fact, the limitations facing the industry at this point aren't so much based on technical feasibility as they are on establishing a range of applications which would justify the initial expense of establishing volume production of such components.

Particularly with the enormous financial potential of developing medical, and so called "cybernetic" enhancement devices, no small amount of effort is being expended to explore and define specific applications. Some of the current applications being developed range from micro "scrubbers" designed to scrape plaque from the interior walls of arteries, to complete drug dispensing "systems" on a microchip. A key issue in this development process is establishing a "library" of micro components which a "micro cyberbnetic" device designer can have access to with which to build a complete, self contained system.

The types of components which are of interest in this realm consist of sensors, mechanical actuators, pumps, propulsion devices, micro electronic circuitry, and power supply components. Furthermore, to make such complete, implantable micro systems feasible for long term installation within the human body, biocompatability is of extreme importance. This requires the application of specialized "designer" surfaces to key regions of such implantable devices.

The next most important task in establishing design criteria and mass production capabilities for complex micro assemblies is the establishment of micro positioning and handling equipment capable of resolving to .1 microns, or less, and "secondary" tooling capabilities, such as laser drilling, conductor and multiple substrate bonding, etc., on a similar scale.

As this stage of development continues, the next step is the evolution of design standards, much in the same fashion that designers of integrated circuits rely upon now. In today's world, a "chip" designer uses a computer aided design (CAD) system to provide a visual map of submicron features, such as transistor and conductor sites, during the design process. The designer selects from a library of available components to eventually develop the on screen layout of the chip. This data can then be extracted directly from the computer and translated into the lithographic and other fabrication steps required to mass produce the chip. In the very near future, this same type of design process can be applied to complex integrated micromachine development and manufacture.

To gauge where the technology is at this moment, consider the some of the following examples of assembly equipment, and available components. Originally driven by interest in micro-assembly requirements for mass production of electrooptical micro components, various companies, such as Dukane Inc. of St. Charles, Ill have developed an entire series of micro robotics assembly systems capable of resolving repeatable motion paths to .1 microns over a total work area envelope of 115 x 50 x 50 mm. A typical work area for a micro assembly would be in the realm of 50 x 50 microns, and could incorporate such tasks as handling and placing subcomponents of mixed material substrates on a common "foundation" substrate, resulting in a complete machine system construction.

Given that assembly systems are already available that can handle components and materials at the submicron scale, the next step is chip manufacturers, with the substrate foundry and lithographic fabrication equipment already on line producing integrated circuits, to develop the "mask" patterns for micro motor, actuator, and sensor components. This process has already started. Toshiba America, in San Jose, CA, has already produced a complete, commercially available micromotor that fits on the head of a pin, and operates at up to 50,000 RPM on 1.5 to 2 volts. But more importantly, a micro machine designer is not specifically confined by what is "off the shelf", since an already substantial array of micro mechanical mask configurations have been successfully implemented at various research facilities. The task facing the micro machine developer is to approach the appropriate fabrication vendor with micro lithography facilities, and present them with a custom mask, much the same way that one would have a custom integrated circuit fabricated.

There are literally hundreds (if not thousands) of such facilities worldwide, far too numerous to list here. Again, the emphasis here is not the exploration of some far off fabrication concept, but rather the design of a specific micro component system, and having the resultant components fabricated at an existing service bureau tooled up for this type of production.

Micro mechanical components can be generally categorized into two main types of configuration. Single piece constructions such as "tweezers", grippers, harmonic vibrating vanes, and related structures can be etched directly from a common mass of piezo-electric substrate. Complex structures, such as actual motors with gearing and motion translation devices, and valve and pumping assemblies, require fabrication from separate materials, and final assembly with a micro assembly system (as mentioned above).

The next type of component required for an implantable "intelligent" micro-machine that would perform some type of interactive process within the human body is a sensor device, or an array of sensor devices that can allow the machine to recognize or respond to a stimulus. For instance, an implantable insulin dispensing micro-machine would need to able to continuously monitor glucose levels within the blood in order to regulate the rate of insulin dispensation from a controlled valve device.

The realm of electronic and electrochemical biosensors is actually very diverse, and even in current technology provides a diverse range of sensitivity to different types of stimuli. Ion selective, complex compound, enzyme and immunosensors are all becoming available as integrated components. Furthermore, even such "exotic" areas sensitivity, such as microphotonic, extremely minute pressure fluctuations, and microsonic detection are all becoming available as "sensor sites" on an integrated hybrid micro circuit. Of particular interest are chemically sensitive field effect transistors (chemFETs), in which a single transistor is electrically bonded to an ion selective membrane. This allows the micro sensor designer to place an entire array of multiple sensors and signal processing electronics on a single chip.

In fact, the continued "shrinking down" of micro sensor sites on an integrated circuit substrate has coincided with an entirely new collection of biocompatible materials and "intelligent" membranes and gels. These various gels and membranes posses the features of changing relative size or volume, or relative molecular porosity (depending on the application) as a function of pH, electrical, or thermal sensitivity. Not only these materials interesting for sensor or chemical valve applications, but also mechanical work performance as well, such as artificial "muscle fiber" and micro actuators.

For instance, a collection of gel fibers 1 micron thick can shrink to 4 percent of their original volume in less than 1 millisecond in an electric field of 5 volts pre millimeter. This allows for relative volume displacement to be triggered by electrochemical reactions. This also provides a perfect pumping device for dispensing a substance in micro dosages, with no mechanical moving parts, as in a "traditional" pumping device.

Back to the insulin dispensing micro machine mentioned earlier, a research team from the University of Trondheim in Norway and the VA Islet Transplant Center in Los Angeles, CA has in fact already demonstrated that microdosages of insulin can be directly osmosified out the gel itself with a minute electrical current. This means that an entire micromachine device can provide this function without requiring any type of mechanical pumping components. In fact, human trials for a micro implantable device based on this technology are expected to begin by the end of this year.

But this is only one very narrow application example of a much wider array of molecularly selective membranes, which depending on very minute fluctuations in applied current, can be programmed to allow for an entire range of molecular porosities with the same piece of gel. This is an extremely important function for micro machine designers who want to have their intelligent machines "sniff" out certain chemical compounds, but ignore others in a complex chemical environment. The point here is that if micromachines are going to be implanted throughout the human body to various tasks, their ability to perform is going to be directly dependent on their ability to sense, and "home in" on the chemical messages that they are programmed to look for.

In Japan, the application of intelligent gels has in fact been specifically directed towards artificial muscle development. At the Second Polymer Gel Symposium and Robo-bug Fest in Toshuba, Japan, nine research groups successfully demonstrated chemomechanical motive devices, and serious development funding is being directed at propelling this new technology into the medical devices marketplace. The concept of "wetware" being applied to micro chemistry dispensing and monitoring systems, and artificial muscle components, is a major development for cybernetic and micro machine designers.

In conjunction with this, the application of biocompatible surfaces to almost any type of metallic or polymer surface is yet another key ingredient for this design process. This is already being provided as a commercially available service by several companies, such as Spire Corp., Bedford MA, Advanced Surface Technologies, Inc., Billerica, MA, and Bio-Metric Systems, Inc., Eden Prarie, MN. The major objective is to provide a series of chemical "tethers" which can attach the biochemical substrate of choice to the micro machine device surface according to the designers requirements. One major advance in this realm is the introduction of a series of photoactivated reagents, which set up the chemical bonding sites as a series of photo exposure patterns. This means that the same micron level sized features used to create the physical topologies of the micromachine being constructed, can later be applied to attaching biochemical substrates. Various biomolecules, including antibodies, enzymes, extracellular matrix proteins, peptides, antithrombogenic agents, even entire cells, have in fact already been applied to medical implant devices with this process.

For anyone interested in the future of micromachine development, consider this. According to market research conducted by Market Intelligence Research Corp., Mountain View, CA. Total micromachine development and sales in 1992 was $995 million, and is expected to exceed $3 billion by 1998. What this translates to is that the market potential of micromachine development is attractive enough to redirect the attention of substrate foundries, microfabrication facilities, and producers of development tools to make this technology readily available to the "outside" world of entrepreneurs and independent designers.

What has been discussed so far is what is already available to the micromachine developer. The near future, however, is beginning to cross the boundary from micro scale machined components, and enter truly nano scale fabrication and construction technologies. Furthermore, biophysicists are beginning to examine the inner workings of complex organic molecules and processes from the point of view of being able to synthesize these processes as molecular construction techniques. The major objective that all future nano scale "system" designers are faced with is the molecular and atomic precision with which such constructions can be replicated.

Traditional micro lithography fabrication technologies, pushed to ever smaller tolerances, begin to fail below .1 micron feature sizes, mainly because of the "raggedness" of the micro surfaces and edges of an etched substrate. It is at this point where the precise deposition of atoms and molecules onto a substrate, rather than the "carving away" of excess material, becomes the requirement for constructing nano scale components.

Although not yet available as a commercial service, various types of nano fabrication processes are being currently in the experimental stage at a variety of research facilities. For instance, in the realm of nano electronic devices, a new class of transistors, referred to as "high electron mobility transistor" (HEMT), are emerging as nano components for future nano circuitry. In this realm, the gate of the transistor is essentially a wave guide for single electron transmission, where the "wall" dimensions of the quantum conductor path is less than the actual resonant wavelength of the electron being conducted through it.

Astonishingly, this theoretical concept has already been successfully proved and tested by Peter Nuytkens and his research team at MIT. In fact, they have already constructed an entire A/D (analog to digital) converter circuit with these atomic scale transistors. Perhaps even more amazing are the quantum well lasers in which a single electron and resulting quantized photon are the source for an electrooptic logic device. Devices based on this type of quantum well construction would utilize 10 nm features on a molecular substrate.

In yet another area of research into molecular scale devices, photodetector "cells" occupying a region of 2 nm x 2nm are being developed by Elias Greenbaum, a molecular electronics researcher at Oak Ridge National Laboratory (Oak Ridge, TN). In this example, photosynthetic molecules which mimic the organic behavior of photosynthesis in plants are being applied as molecular "patches" on a carrier substrate. A photodetector array based on this concept not only provides photonic resolution far beyond current commercial technology, but also sensitivity capable of "sensing" individual photons.

It is at this point that perhaps the first glimpse of the Drexlarian world of future molecular construction processes are beginning to appear on the horizon. In fact, the merging of the micro machine world, and molecular construction is already being considered at some facilities.

Utilization of arrays of micromechanical "robots" to manipulate genetic samples for DNA scanning and reconstruction is in fact already being considered by Johannes Smits, a micromachine researcher at Boston University. The concept here is to construct micromachine matrices containing thousands of genetic samples, which would then be "examined" for specific genetic codes by thousands of micro robots which process these samples in parallel, rather than having to rely on the serial, sequential sampling process as is conducted by current computer controlled systems.

This example of the symbiosis between micro machine component development, nano structure fabrication techniques, and potential biogenetic engineering in the near future indicates the rapid pace at which these developments are converging to provide a future world of micro and nano cybernetic "enhancements" to humans.

For More...
Read Charles Ostman's Internet as an Organism article and more for Members Only INSIDE 21st Century Magazine.

Charles Ostman

Charles Ostman is founder and president of Berkeley Designs, a company which specializes in the development of specialized 3D visualization and rendering software. This includes VR worlds, customized procedural texturing and special effects software tools, and related software development. Berkeley Designs also creates fine art and apparel products which feature "virtual world" art created with this specialized software.

Mr. Ostman serves as Contributing Editor and author for Midnight Engineering Magazine, a technical trade journal for the entrepreneurial engineer. He is also Technical Editor and author for Mondo 2000, a "cybertech" culture futurist publication. Mr. Ostman has authored numerous technical papers on nanotechnology, engineered materials, virtual reality, 3D imaging and CAD applications, and neural net and other cognitive process engines.

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