Nanotechnology: Definition & Products - Can we see the birth of molecules? What really happens to atoms during chemical reactions? Can we move atoms? Can we actually visualize biological processes at the molecular level? The answer to all of these questions is yes. Today, because of the advent of new instrumentation like the family of scanning-tunneling microscopes, scientists can now pick up and move atoms, and, with the use of molecular cameras, they can take photographs as fast as one quadrillionth of a second (a femtosecond). Scientists can image the step -by-step changes that occur in atoms and molecules as chemical reactions progress.
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As was discussed in the Human Endeavors box in Chapter 2, scanning-tunneling microscopes ''feel" the surface of the molecular or atomic specimens to form the image. A tiny platinum probe is given a small electrical charge and the specimen is scanned, atomic diameter by atomic diameter, across its surface. As the probe moves, electrons respond to the voltage differential between the probe and the surface of the specimen by tunneling across the gap, which produces a very small current. The variations in the currentwhich are due to the miniscule differences in the distance between the probe and the objectare detected. The computer produces the image from these distances.
In 1989, Donald Eigler and Erhard Schweitzer of IBM in San Jose, California, lowered the temperature of a plate of nickel to about absolute zero (-456° F), which minimized atomic vibrations. Then, by spraying atoms of xenon gas over the plate and by increasing the electrical charge on the probe of the scanning-tunneling microscope, they were able to drag the xenon atoms across the nickel to spell out "IBM" in letters only five atoms tall, the entire logo only about 660 billionths of an inch long (Figure A). This example of the manipulation of materials, be they inorganic or organic, atom by atom, is what is meant by nanoengineering. The new nanotechnology combines the technological capabilities of the scanning-tunneling microscope with laser cameras that can detect changes that occur in quadrillionths of a second, and you can image what happens in atoms and molecules as they react. The synchroton ray camera can do just that. When you pulse an atom with a specific frequency of energy, the atom will absorb that energy and the electrons are moved to a higher energy state. When the electrons return to their original ground state, energy of a specific frequency is emitted. Using this principle, scientists can pulse molecule A and molecule B and detect how their frequencies change to form molecule C. But how can you do that and how can you record the snapshots or "frames" of this continuous event, since it only occurs in quadrillionths of a second? Figure B illustrates how this camera works.
So today we can see the advent of a new technology even more exciting or as exciting as genetic engineering. Not only can we now manipulate genetic variation, but we can actually manipulate atoms and molecules. With this technology our advances in science, including biology, will truly expand. Just think, today not only can we image atoms, but we can manipulate them as well and detect the actual events in the birth of new molecules as atoms and molecules react.
Source: Zewail, Ahmed H., "The Birth of Molecules," Scientific American, 263:6, Dec. 1990, pp. 7682. - See more at: http://www.biologysmart.com/2015/07/the-functions-of-carbohydrates-in-body.html#sthash.RXSQcqFS.dpuf
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