Nanomedicine, Volume I: Basic Capabilities
© 1999 Robert A. Freitas Jr. All Rights Reserved.
Robert A. Freitas Jr., Nanomedicine, Volume I: Basic Capabilities, Landes Bioscience, Georgetown, TX, 1999
22.214.171.124 The Mechanical Tradition
The late science fiction author Robert A. Heinlein155 nearly invented the concept of molecular nanotechnology in 1942 when he suggested a process for manipulating microscopic structures. Heinlein envisioned the extensive use of life-size teleoperator hands, called "waldoes," complete with sensory feedback for full, remote-controlled telepresence. His fictional hero, Waldo, used a collection of these mechanical teleoperated hands for building and operating a series of ever-smaller sets of such mechanical hands. The smallest mechanical hands, "hardly an eighth of an inch across," were equipped with micro-surgical instruments and stereo "scanners," and were used to "manipulate living nerve tissue, [to examine] its performance in situ," and to perform neurosurgery. Eric Frank Russell's 1947 story "Hobbyist" described a fabrication process with "atom fed to atom like brick after brick to build a house." In 1955, Russell's serial "Call Him Dead," also published in Astounding Science Fiction, had a virus-based alien intelligence that spread through contact with blood or saliva; the story features a "microforger," a man who makes "surgical and manipulatory instruments so tiny they can be used to operate on a bacillus." Also in the mechanical tradition, Isaac Asimov's "Fantastic Voyage"339,340 in 1966 took its miniaturized human crew in a miniaturized submarine through the bloodstream of a human patient on a mission of repair.
Heinlein, Russell, and Asimov overlooked the full implications of their ideas, and most scientists were unsympathetic -- for example, in 1952 Erwin Schrodinger wrote that we would never experiment with just one electron, atom, or molecule.3197 But by the early 1960s, several scientists had reinvented similar approaches to micromanipulation and miniaturization, this time extending their reach into the nanotechnology domain. The first and most famous of these scientists was the Nobel physicist Richard P. Feynman. In his remarkably prescient 1959 talk "There's Plenty of Room at the Bottom," Feynman156 proposed employing machine tools to make smaller machine tools, these to be used in turn to make still smaller machine tools, and so on all the way down to the atomic level. Feynman prophetically concluded that this is "a development which I think cannot be avoided." Such nanomachine tools, nanorobots and nanodevices could ultimately be used to develop a wide range of submicron instrumentation and manufacturing tools, i.e., nanotechnology. Feynman's suggested applications for these tools included producing vast quantities of ultrasmall computers and various micro- and nano-robots.
Feynman was clearly aware of the potential medical applications of the new technology he was proposing. After discussing his ideas with a colleague, Feynman offered the first known proposal for a nanomedical procedure to cure heart disease: "A friend of mine (Albert R. Hibbs) suggests a very interesting possibility for relatively small machines. He says that, although it is a very wild idea, it would be interesting in surgery if you could swallow the surgeon. You put the mechanical surgeon inside the blood vessel and it goes into the heart and looks around. (Of course the information has to be fed out.) It finds out which valve is the faulty one and takes a little knife and slices it out. Other small machines might be permanently incorporated in the body to assist some inadequately functioning organ."156 Later in his historic lecture, Feynman urged us to consider the possibility, in connection with biological cells, "that we can manufacture an object that maneuvers at that level!"
In 1961, K.R. Shoulders2265 rejected the use of biological building blocks, even though biological "processes do work, and they can do so in a garbage can without supervision." He saw them as too limited environmentally and too difficult to control with available technology. Instead, he sought to directly produce much simpler, more powerful and rugged nanostructure arrays, operating at video frequency rates, which in turn could ultimately aid in their own replication. In 1965, Shoulders2266 reported the actual operation of micromanipulators able to position tiny items with 10 nm accuracy while under direct observation by field ion microscopy.
In 1970, Volkenstein2267 noted that "the creation of a nonmacromolecular system which would act as a model for living organisms is definitely possible" but could not arise by itself, and that the macromolecularity of present organisms is not essential, but due to their evolutionary origins. Taking some poetic license, he added: "Consequently, the cybernetic nonmacromolecular machine, which simulates life, could have been and can be created on earth only by man. Then it could perfect itself without limits." T. Nemes2268 discussed artificial self-replicating machines and described how to construct "an automatic lathe able to reproduce itself," a concept apparently developed before von Neumann's work on machine replication.1985
In 1981, Drexler182 suggested the construction of mechanically deterministic nanodevices using biological parts; these devices could inspect cells at the molecular level and also repair cellular tissues that had been damaged during cryonic suspension. In 1982, Drexler311 described cell repair machines even more clearly in the mechanical tradition, in a popular publication.
By 1983, Drexler2253 began privately circulating a draft technical paper entitled "Cell Repair Machines" which investigated for the first time, in some detail, whether an advanced mechanical-based nanotechnology would "permit construction of systems of molecular-scale sensors, computers, and manipulators able to enter and repair cells; the nature of the computational algorithms and magnitude of the computational resources needed to guide repairs; and the physical capabilities and constraints important to the repair process [in order to] sketch the conceptual design of a cell repair system based on a mature molecular technology."
Peterson2254 notes that "medical applications were explored by Drexler during the early 1980s but the medical community was not ready for the concept." A technical paper by Drexler, invited by an editor at the Journal of the American Medical Association, was dismissed by a referee as "science fiction."
In 1985, G. Feinberg2269 proposed using short-wavelength coherent laser energy to power and communicate with "nanosensors that could be implanted into the human body. They could...[monitor] various physiological functions from subcellular molecules up through tissues and organs...essential in determining some of the mechanisms involved in growth and aging."
In a 1985 book entitled Robotics, edited by Marvin Minsky (a well-known computer scientist and artificial intelligence pioneer), Minsky briefly described how fully-automatic cellular repair machines might work, following Drexler's vision:
"Suppose that we could design a repair machine so small that it could repair an artery from the inside! The first such machines might be the size of fleas. (There is room for a great deal of machinery in something the size of a flea -- as the body of the flea itself testifies.) These micromachines could crawl into all but the smallest blood vessels, clear out debris, and reline the walls with suitable materials yet to be invented. Later generations of micromachines could be even smaller, perhaps no larger than the body cells they repair. These minuscule machines would be mass-produced by the billions, either by larger machines or by techniques of making them reproduce themselves. Perhaps these biological janitors would even be implanted in our bodies to remain there as permanent maintenance workers, just like many biological cells that already serve such purposes."
"Today the idea of such a technology may seem fantastic, yet many of the circuits in our computers are already smaller than many of our bodies' cells. Let's try, for a moment, to look ahead to: mass production of highly intelligent machines; gigantic advances in miniaturization; a technology so advanced that these machines reproduce themselves without our help. Fantastic? Not at all. Even the simplest algae and bacteria can do that. True, they're not intelligent, but each of them contains enough computerlike machinery and memory to do those things. So, to build bacteria-size computers should be perfectly feasible, once we have the necessary microtechnology. Some day we'll have the means to build artificial, cell-like machines with all those capabilities."202
R.A. Freitas Jr.204 also contributed a chapter to Minsky's 1985 book, offering the following suggestion for remote-controlled incisionless nanosurgery: "One possibility is the concept of remote-controlled medical mites made feasible by modern micromachinery technology. Some medical mites would be like microminiature submarines, released inside the human body for internal sensing. Other mites could float, crawl, or swim through major arteries in the human body and perform on-site repairs from within, controlled by radio link under direction of a skilled telemicrosurgeon."
In 1986, Drexler published Engines of Creation,8 a popular text with two chapters devoted to discussions of cellular repair machines. Drexler further expounded upon the topic of cellular repair machines in articles published in 1985,259 1986,310 1987,165 and 1989,72 and his concepts were described by Brian Wowk in 1988261 and in a Time-Life book in 1989.2256 Cellular repair machines are explored at length in Chapter 21.
In 1988, A.K. Dewdney18 reported an early nanomedical concept of an artery-cleaning nanorobot that he attributed to Drexler, accompanied by an artist's conception with the caption "a nanomachine swimming through a capillary attacks a fat deposit." (A preferable nanorobotic design for this purpose, the vasculocyte, is presented in Chapter 22.)
Last updated on 5 February 2003