Nanomachines the Science of Molecular Size Machines

Nanomachines

The Science of molecular size machines and its engineering designs and constructions until late 1980s were not considered practicable. Nanotechnology, according to the leading exponents of that time were neither feasible nor viable, due to the fact of total structural difference of the constituent of nano-molecular device i.e. Atoms from the mechanical objects of every day life. The essential components of engineering mechanics i.e. cogwheels, gears or motors could not be imagined to have formed by means of atoms, that are characterized by fuzzy and unsubstantial contents having no definite location position. Edwin Schrdinger, a leading quantum theoretician, regarded the particles as not permanent entity but an instantaneous event and derived the conclusion that atoms could no longer be regarded as "identifiable individuals." Werner Heisenberg, with extreme pessimism described atoms as "a world of potentialities or possibilities" rather than "of things and facts." (Is the future nano?)

Such ideologies succeeded making the scientists of that time convinced to view nanotechnology as an unattainable objective. During the second half of the 20th century some scientists however, ventured to explore the prospects of the subject. The efforts began with coinage of the terminology of molecular engineering by Arthur Von Hippel, an electric engineer of Massachussetts Institute of Technology (MIT) during 1950s and with his optimistic predictions for possibilities of the constructing nano-molecular devices. Contemporary Nobel laureate and physicist, Richard Feynman revolutionized the concept through his lecture "There is plenty of room at the bottom." (Is the future nano?) K. Eric Drexler, set up the organization "Foresight Institute, Palo Alto at California, in 1986 for popularization by the concept of building materials and products with atomic precision. Presently, scientists consider it as the pioneer organization for development of nanotechnology.

Questions still arise in the present scenario with regard to the progress of development of nano-technology. Even though much has been achieved in the field, the dreams have not yet been fulfilled till now. However, developments and intensive research in the field have given rise to revealing of new features of atoms, such as robustness of atoms to exist independently, facilitating isolation and counting in units. This feature of atoms gives strength to construct reliable parts of working nano devices. Currently, we have the capability to make the atoms move around so as to place them in desired locations. These achievements in less than past two decades have led to Nobel Prize winning contributions in the field. The remarkable contributions of Dehmelt of University of Washington in Seattle, revealing stability of even subatomic particles enabling its isolation within magnetic traps for months together is noteworthy. (Is the future nano?)

Table 1. Prizes for elucidating atoms and subatomic particles

Nobel prize

Winners

Achievement

Gerd Binnig, Heinrich Rohrer

Scanning tunnelling microscope

Hans Dehmelt, Wolfgang Paul

Traps to isolate atoms and subatomic species

George Charpak

Subatomic particle detectors

Clifford Schull,

Bertram Brockhouse

Neutron diffraction techniques for structure determination

Steven Chu,

Claude Cohen-Tannoudji,

William Phillips

Methods to cool and trap atoms with laser light

Source: Is the future nano?)

Devices constructed from individual atoms are called Nanomachines. According to some researchers; in future, to combat disease, nanomachines will be able to enter living cells. Nanomachines, which can reorganize atoms in order to make new objects, can be built in future, according to the researchers. Nanomachines, if the researchers succeed, can be used to get rid of poverty by obviously converting dirt into food. Nanomachines are incredibly small devices, as the terminology indicates. They are constructed from individual atoms and their size is measured in nanometers. (Nanomachines: Nanotechnology's Big Promise in a Small Package)

There is no macroscopic analogue for Nanomachine. By atomic scale "pick and place," nanomachine would make any structure, including itself, that is, a set of nanoscale pincers would pick individual atoms from their surroundings and place them where they should go. (Nanotechnology: Nanomachines) Futurist and visionary K. Eric Drexler made famous the capability of nanomachines during the 1980's and 1990's. K Eric Drexler coined the concept of nanotechnology during 1986, and made public in his publication of Engines of Creation. Drexler visualized the possibilities of efficient construction of objects at molecular level with the help of microscopic machines which were predicted to be the solutions for many ailments of the present world. (Book Review: Unbounding the Future: The Nanotechnology Revolution by K. Eric Drexler and Chris Peterson with Gayle Pergamit)

The production of the 'assembler' is the eventual goal of nanomachine technology, as per Drexler. The nanomachine assembler is intended to influence matter at the atomic level. The assembler will be used to move atoms from existing molecules into that of new structures and will be built with small 'pincers'. The idea is that the assembler should fabricate useful items from raw material by reorganizing atoms. If one can scoop dirt into a vat and be patient, a team of nanomachine assemblers can change the dirt into an apple, a chair, or even a computer, and this is the theory. A molecular schematic of the object to be built is to be put up into the memory of the machines in the vat. Then they would fabricate the chosen item by methodically rearranging the atoms enclosed in the dirt. (Nanomachines: Nanotechnology's Big Promise in a Small Package)

Though some primordial devices have been tested, Nanomachines are mainly in the phase of research development. A sensor with capability to count specific molecules in a chemical sample, and having switched approximately 1.5 nanometers across, is an example. Medical technology is the field where nanomachines will find applications firstly to recognize pathogens and toxins from the samples of body fluid. (Nanomachine) Nanomachines can be used in the field of pharmaceuticals, to watch over symptoms of change in a patient, to treat cancer, AIDS and to use it for operations of those areas which are difficult for operating upon. (The Ethics of Nanotchnology) It could be used to produce carbon fibers which would be as strong as Diamond and which also be less expensive than plastic. Also an important aspect of nanomachines is that this technology is comparatively less expensive, clean and also which is easy to maintain than other technologies which are presently available. (Book Review: Unbounding the Future: The Nanotechnology Revolution by K. Eric Drexler and Chris Peterson with Gayle Pergamit)

http://cseserv.engr.scu.edu/StudentWebPages/AChen/img/FigRes5BS.jpg

Respirocytes with Red Cells.

(by Vik Olliver, 1998)

The Ethics of Nanotechnology. Retrieved at http://cseserv.engr.scu.edu/StudentWebPages/AChen/ResearchPaper.htm

For decades, scientists' brains are filled with the development of nanomachines. The discovery of bio-molecular motors, such as myosin, kinesin and dynein, roughly 20 years ago, was the starting point for the dream of constructing machines which had the capacity to copy, replace or to work in recital with existing bio-molecular machines. The understanding of the biophysical and biochemical properties of bio-molecular motors have been enhanced by present day technologies which help to watch, influence and analyze particles or molecules at the nanometer scale. Proteins are the bio-molecular motors, which generate forces and movements within cells, that is, transforming chemical energy into mechanical energy. The diverse functions of these proteins are such that some are accountable for rotation and mobility of cilia, DNA replication, organelles transport, etc. (Bio-Molecular Motors Research in Japan: Asian Technology Information Program)

As an example, the mechanical activity of bio-molecular motors is sustained by the hydrolysis of ATP (adenosin-triphosphate), the "fuel," which turns out energy for the processive movement of kinesin along microtubes or the contraction of the actin/muosin complex in muscles. The purposes of bio-molecular machines cannot be read by equivalence to artificial machines, as they are not simple. Molecular machines and proteins have an active structure and have size in comparison to the nanometer range. Also, thermal energy can be matched up to the input energy to the molecular machines and when shown to thermal agitation, the molecular machines function at very high efficiency.

The artificial machines come in contrast with molecular machines, as artificial machines use much higher energy than thermal energy to work quickly, deterministically and precisely. Hence, on such grounds, an understanding of the dynamic properties of proteins and their interactions among themselves is essential. The development of Single-Molecule Detection (SMD) techniques to straightforwardly check the dynamics of proteins and molecular machines have been extended to encompass a wide variety of biological sciences. SMD techniques, in amalgamation with nanotechnology developments, will be more influential in directing more research in development of nanomachines and that of bio-molecular machines. (Bio-Molecular Motors Research in Japan: Asian Technology Information Program)

These machines mostly consist of proteins which are synthesized out of carbon- the chief ingredient of all living things. And as Drexler explained, these machines, called as assemblers, will be built on the basis of one atom at a time, with the capacity of being able to fit several hundreds within a single cell. That these man-made nano-assemblers will add innumerable variety to the countless life forms that are currently known is agreed from both sides of the debate. This is due to a number of appealing differences between the assemblers and the biological cells on which they are based. The replication instructions within these hybrid biological/mechanical machines to be designed by engineers will be composed of computer code instead of DNA is one such difference worth mentioning.

However, these machines still look like and perform as existing cell types and this is what Drexler and other engineers and nanobiologists foresee. Viruses are composed of proteins and coding material and its replication is possible only within a host organism and this nature of viruses will be built into some assemblers. A virus-like assembler, after entering a cell, utilizing the freshly introduced coding information, can instruct the cell's own internal machinery to replicate. Other assemblers similar to bacteria will carry within their own firm boundaries, all the materials which are required for biosynthesis, and hence would be independent. They might also make alterations improving or redesigning the original cells by becoming organelles within eukaryotic cells, and are also similar to bacteria in this respect. (Nanomachines and biological systems: Utopia or Dystopia)

Today's surgery of using a massive blade cutting through a crowd of cells, killing thousands, will appear pretty barbaric from a cell's point-of-view. To stitch up the damage, a thick cable is towed in, and for healing to take place, it is left to the cells to discard their dead and multiply. The administration of a drug to a patient from the cell's point-of-view can be visualized as follows: the drug molecules, before recognizing specific molecules by "touch," knock pointlessly around till they get adjusted into their target molecule. Compare this to a molecular machine equipped with a nano-computer that holds data on the structure of all healthy tissue, which can feel, prepare, and act at this level.

It is possible to build repair machines with a size of a bacterium, which can enter and leave cells, can wipe out intruders in the blood cells and can even check the DNA itself for any mistakes. Nowadays, doctors depend on drug molecules and the cell's capability to mend itself, when a cell is damaged, even though this process does not always bring the patient back to health. In future, doctors can restore cells that have been damaged to the point of inactivity with the help of nano-devices, which can repair on the smallest components of the cell. These machines can reconstruct injured molecules inside the cell by getting to the base of the problem. (The Promise of Nanotechnology)

Nanomachines can provide support to the immune system, because these machines can fight with natural nanomachines, viruses, and because the body's own immune system has some limitations like not remembering the shape of its enemies, failing to identify malignant cells and delaying full development of immune reaction. Nanomachines can make a mammoth contribution to ageing, can affect bacteria, can influence tumors and also help in remodeling damaged tissue. (Nanotechnology and Medicine) The daily work of the body is done by the molecular machines. Muscles affect our motions while we chew and swallow. The bundle of molecular fibers, enclosed in muscle fibers, compress by sliding against others. The molecular machines in stomach and intestines, called digestive enzymes, break down the complex molecules in food into smaller molecules and these are used for the purpose of fuel or are used as building blocks. (Unbounding the Future: The Nanotechnology Revolution)

Useful molecules are carried to the bloodstream by the molecular devices which are found in the outer layer of the digestive tract. The molecular storage devices which are called hemoglobin enhance oxygen in the lungs. The heart, driven by molecular fibers, pumps blood loaded with fuel and oxygen to cells. Contraction in the muscles is based on sliding molecular fibers and is driven by fuel and oxygen. In the brain, the molecular pumps that influence nerve cells are done by nanomachines. Molecular machines in the liver that build and break down a whole mass of molecules are influenced by nanomachines. Such a process is repeated in other parts of the body. (Unbounding the Future: The Nanotechnology Revolution)

Nanomachines which can make replica of themselves are another objective of nanotechnology. A machine can be able to construct replica of it, if it can reorganize atoms in order to build new materials. Products which are thus made by nanomachines will be extremely low-priced, if this objective is achieved. This is because, the technology, once fine tuned will not need specific materials, which might be uncommon and therefore cost money, as it will be self-replicating. Nanotechnology will sign an end to traditional financial systems is the forecast of Arthur C. Clarke. A world of stimulating promises will open up, if scientists would be able to design nanomachines which would have the capacity to reorganize atoms. Advanced treatments for many diseases can be given by nanomachines which are modeled for different purposes. Injecting medical nanomachines, programmed to recognize and disassemble cancerous cells, into the bloodstream of cancer victims, can provide a rapid and efficient treatment for all types of cancer. Damaged tissue and bones can be mended by nanomachines. (Nanomachines: Nanotechnology's Big Promise in a Small Package)

By building molecular support structures by reassembling nearby tissue, they could even be used to toughen bones and muscle tissue. Medical science will speedily adopt treatments for most of the human illnesses which will have the capacity to influence human cells at the minute level. These treatments will be cheap and accessible to the whole people because nanomachines will be designed in such a way to make copies of them. If nanotechnology is proved to be effective, problems relating to shortage of food problems of hunger can be solved. As nanomachines can have the capacity to change anything into food, this food could be used to solve problems of hunger worldwide.

Food produced by nanomachines would be less expensive and would be available to all. As in the case of food, which enables to influence the ever-increasing population, nanomachines would be able to produce other goods as well. Also clothing, houses, televisions, cars and computers would be made possible at less money. As nanomachines will change all garbage into new goods which can be consumed there need not be worries in relation to the garbage produced. (Nanomachines: Nanotechnology's Big Promise in a Small Package) Another advantage of using nanomachines is that individual units would require less energy to operate. Nanites would exist for centuries before collapsing and hence robustness is another potential asset. (Nanomachine)

The finding of toxic chemicals and measuring of their concentrations, in the environment is another prospective application. High operational speed is possible due to the microscopic size of nanomachines. (Nanomachine) This is because all machines and systems will be likely to work faster as their size reduces. Nanotechnology can resolve environmental problems like ozone depletion and global warming. By releasing clouds of nanomachines into the upper atmosphere, these nanomachines can methodically destroy the ozone reducing chlorofluorocarbons (CFCs) and build new ozone molecules out of water and carbon dioxide.

As water and carbondioxide both contain oxygen, the atmosphere contains an abundant supply of oxygen atoms; and so ozone (O3) can be built out of 3 oxygen atoms. Teams of dedicated nanomachines could be engaged to destroy the surplus CO2 in the lower atmosphere while the ozone building teams are at work in the upper atmosphere. CO2 has been recognized as one of the major contributors to global warming and is a heat trapping gas. To bring back the planet's ecosystem and to stop global warming, surplus CO2 has to be removed, which can be done by nanomachines. All species on earth will be profited by this. A new era for humanity will begin once the nanotechnology is perfected and nanomachines are produced. This will quickly lead to the end of hunger, illness, and environmental problems. (Nanomachines: Nanotechnology's Big Promise in a Small Package)

The intermingling of nanotechnology in the form of nanosize particles into the mainstream is evident in the products of everyday use such as sunscreen, paint, cosmetics, and industrial coatings awaiting its more extensive uses in the near future. Minimization of side effects of the drugs through the preparation of accurate combinations with the help of nanoparticles is experimented in the field of Pharmaceuticals. Eradication of diseases like cancer warranted coating of the receptors of cells with nanoparticles of drugs that inhibits the reproductive cycle. Use of Nanosensors for check up of the health of astronauts is being explored by the NASA and the University of Michigan.

The aim is to explore the method of infusing the blood cells of astronauts for continuous monitoring of the exposure to radiations or other infectious agents. Dendrimers and synthetic polymers having a diameter of less than 5nm are the constituents of the devices. This involves the infusion of nanosensors into white blood cells, for detecting the symptoms of biochemical changes due to radiation. The fluorescent tags are attached in order to make the dendrimers glow with the location of proteins related to cell death. Development of retinal scanning device with laser that detects fluorescence from lymphocytes while passing through the capillaries behind retina is under progress. Taking up of blood samples and transplantation of larger sensors resulting in inflammation or infection is being avoided by use of nanosensors. (A king-size future for nanosize machines: nanotechnology researchers are laying the groundwork for atomic-scale engineered systems)

Many controversial debates were attracted by the concept of Nanomachines which is considered to be a bold step in mechanics. The developments however have been able to restore a degree of confidence among the people irrespective of the fact that many hurdles are to be overcome for its fruitful implementation. Remarkable achievements in this direction are due to the recent developments of the science towards construction of first molecular assemblers. Demonstration of two researchers of IBM in the field of scanning-tunneling microscope by spelling out the initial of the company on the atomic scale using 35 Xenon atoms showed advancement in this direction that proved the capability of moving of single atoms with great accuracy. These developments will lead to occurrence of the second industrial revolution within a decade. (A king-size future for nanosize machines: nanotechnology researchers are laying the groundwork for atomic-scale engineered systems)