Nanotechnology: Manipulating Atoms One by One by Robert Kulagowski and Loretta Kulagowski To understand the complex world of nanomachines, a basic understanding of the components must be gained. By definition the word nanotechnology means "technology based on the manipulation of individual atoms and molecules to build structures to complex, atomic specifications." Simply stated, this means using molecules to build larger, more complex structures. Even though nanotechnology is still in its infancy, it is being accepted more widely by the scientific community as something that is within the realm of possibility in only a few years. To begin to explain exactly what nanomachines are, it would be best to start with what they are made of. Normally, when people hear the word "machine", they tend to think of a large noisy object used to produce something. The literal definition of the term "machine" is: "any system, usually of rigid bodies, formed and connected to alter, transmit, and direct applied forces in a predetermined manner to accomplish a specific objective, such as the performance of useful work." A nanomachine is just such a system, but working on a molecular scale rather than on the macroscopic level. One aspect of nanomachines which many people do not realize is the fact that they exist at this very moment. Right now, in every living organism is a multitude of nanomachines whose purpose is to break down proteins, transport molecules across membranes, and even fix errors in the DNA structure of the nucleus. The only difference between the nanomachines in the body and those that scientists hope to artificially create is that man- made nanomachines will be much more general purpose. Nanomachines are made of protein molecules. Since the forces that hold proteins together are very weak, the probability that the protein would fold in the correct way is astronomical. This makes creating a large protein molecule extremely difficult. Current technology allows biochemists to create amino acid sequences from scratch, but with no guarantee as to the structure that will develop. Biochemists are now trying to figure out how to make a sequence of amino acids fold the right way. The best computer programs today still cannot predict how a given sequence will fold. On the other hand, engineers do not think the same way that biochemists do. The engineers are not trying to predict how natural proteins will fold, but are trying to design a long protein chain that will fold predictably, which makes the engineer's job easier in a sense. Once protein based nanomachines have been successfully created, the door will be open for nanomachines which are made of tougher stuff. The disadvantage of proteins is that they have a limited range of operating conditions: pH level, temperature and other factors must all be regulated to extreme precision. Nanomachines can serve many useful purposes. One field which can benefit greatly is medicine. Because nanomachines are specifically designed to manipulate single atoms, many of today's ailments can be cured relatively easily. One such condition is arteriosclerosis. In arteriosclerosis, deposits of cholesterol build up on the inner walls of arteries, causing them to narrow. This condition is most serious when the coronary arteries are involved. Although the heart is a small organ, it uses 1/5th of the blood supply for its own needs. When the blood flow is sufficiently restricted, tissue which is fed by that artery begins to die. The first sign of narrowed arteries in the heart is a condition known as angina, which causes sharp chest pain. As the condition worsens, the heart muscle will begin to die, which will cause a heart attack. However, a nanomachine can be programmed to search for deposits of cholesterol and remove them, thereby re-opening the artery. Cell repair nanomachines would handlethe problems that occur with cells and tissues. For this job, the cellrepair machines would need the assistance of nanocomputersand molecular-sized sensors and tools. These cell repairmachines would compare in size to bacteria and viruses, butbe much more complex. Cell repair machines would travel through the blood stream and would enter the cells as viruses do. Once inside thecell, the nanomachine would determine whether a problem existed by examining the cell's contents and activities. Depending on what was found, it would take the necessary action to either restore the cell to top efficiency or to destroy the cell if it were too far out of operational parameters, as is the case in cancer. In order to control the function of the nanomachine, a nanocomputer would direct their actions. The logic gates would be built by bonding carbon in this fashion: (C Ý C - C Ý C)n where n is the number of units in the chain. The carbon atoms in this chain would form straight rods. Other atoms such as fluorine would be used as logic gates. Memory for the computer would be constructed on the atomic scale with different atoms representing binary 1's and 0's. Because the amount of RAM capacity is virtually limitless on the atomic scale, the sum total of human knowledge could be stored in the volume occupied by a sewing thimble. Since the amount of memory available for the nanocomputer would not be a factor, a nanocomputer would be able to read in the entire DNA sequence for a particular person and make corrections when necessary. Since all physical ailments of the human body are caused by misarranged atoms, cell repair machines would restore these atoms to their correct place, thereby eliminating the problem. As rosy as this may sound, simply repairing the physical ailment would not necessarily fix the main cause. For example, if a person were to have a stroke, the damaged brain tissue could be reconstructed, but any information stored in that cell would be lost. One area that would not be effectively treatable through nanotechnology is mental health. While some types of mental disability would by curable through the restoration of chemical and hormone levels in the brain, others which are not caused by physical means would not be affected. The problem of aging could also be solved by nanomachines. The weakened bones, wrinkled skin, low enzyme activities, slow wound healing, and poor memory, all typical examples of aging, would become unknown. All of the above side effects of aging are caused by damaged molecules, chemical imbalances, and misarranged structures. If cell repair machines could fix the damaged cells and structures, then the aging process would be greatly slowed down. Lives could be prolonged for almost an indefinite amount of time. The average life expectancy of a person could very well range into the hundreds or thousands of years. K. Eric Drexler, a pioneer in the field of nanotechnology, predicts that nanomachines would be able to restore people frozen in cryonic suspension. As a part of the unfreezing process, cell repair machines would fix the problem the person had which caused them to be frozen. Beyond the medical aspect, another field in which nanomachines would contribute is space technology. Because a nanomachine would construct something with precise knowledge of every atom, much of the problems associated with space today could be solved. Entire engines could be constructed in one piece, with no seams or structures that could be jarred loose by vibration. Toxic waste, the scourge of the modern era would be removed from our air, soil, and water. Many possibilities exist for dealing with this problem. One example: dioxin. Molecular machines could be created that simply rearrange the atoms in this substance, which would then render it harmless. To remove lead and other heavy metals, the cleaning-machines would construct a molecule of buckminsterfulerene with the heavy metal in the center. Briefly, a description of buckminsterfulerene: the nanomachine would create a three dimensional lattice of carbon atoms roughly in the shape of a ball. The toxin would still exist, but it would be in an inert form and unable to interact with the external world. Even though the widespread use of nanotechnology is still at least 10 to 50 years away, it will come eventually. The enthusiasm with which the idea of nanotechnology has been received is almost a guarantee that someday in the future nanomachines will be chugging along through our bloodstream with our white blood cells. Bibliography Drexler, K. Eric, Interview with Eric Drexler, Omni, January 1989, pg 66 Drexler, K. Eric, "The Engines of Creation: The Coming Era of Nanotechnology", Anchor Press/Doubleday, 1987 Fromson, Brett Duval, "Where the next fortunes will be made", Fortune, December 5, 1988, pg 185 Monmany, Terence, "Nanomachines to our rescue", New York Times Book Review, August 8, 1988 Young, Jefferey, "Nanocomputer technology proves good things come in small packages", PC Week, February 16, 1988, pg 13 Graciously supplied by Double Helix BBS 1 (212) 865-7043......2400 N81N Listed by KeelyNet BBS 1 (214) 324-3501......2400 N81N