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Computer and Technology |
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"Building Blocks of Nanotechnology" Presented by Matthew Francis
Our November meeting presentation was made by Matthew Francis, Assistant Professor of Chemistry, UC Berkeley. This fascinating presentation took a very difficult to understand subject and explained it in a way that the average person might be able to understand it. Nanotechnology. What it is and what it isn’t. It isn’t something like genetically engineered food that causes concern for some people. It deals with measurement. It is the study of objects in the 10 to100nm (nanometer) size range. One slide put this size in perspective. It showed pictures of various objects arranged in order of decreasing size. A penny coin is less than an inch, 1.9 centimeters or 19,000,000 nm in diameter. The diameter of a human hair is 50 microns or 50.000nm. The smallest component that can be included on a computer chip is 0.2 microns or 200 nm. A virus is 27 nm. A protein is 7 nm. Small molecules are 0.7nm and atoms are 0.05 nm. Current technology limits computer chip design to this minimum size of 200 nm because the technology is based on techniques that utilize light. The wavelength of light is around 200nm. Building blocks are needed in the sub 200nm range. Biology provides this. Chemists are used to manipulating atoms and molecules. Viruses and proteins are the chosen particles. Using 7nm size protein particles, molecules are added by chemical reaction to form a sphere 27nm in diameter. For medical purposes they have developed “Capsids” of this size, which are hollow and have evenly spaced holes in the shell. Receptors on both the inside and outside allow different substances to be added both inside and outside. He explained that the 27nm particle is large enough to travel through the blood stream to deliver the drug that is inside the sphere to the cancer, which is being treated. Chemotherapy tests are in progress using these particles. They expect to have some results in six to 18 months. New Nanocrystals are being studied for application in solar power. They are being used as semiconductors in solar cells. A virus discovered in 1935 called Tobacco Mosaic Virus grows on the tobacco leaf and can be harvested and used as a TMV scaffold. This is a building block with desirable properties. It is composed of 17nm dia. nanorods 300nm long. Alternate energy sources from methanol or ethanol can involve storing energy in the form of gaseous hydrogen. They have discovered that carbon monotubes are a good medium for storage. The hydrogen molecules go to the surface of the monotube and store safely there until heated gently to release them. The United States is the world leader in Nanotechnology. Japan is in second place with Europe third. |