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 Figure 1 - SFM image of vesicles (doped with 1 mol% of a biotinylated lipid) on a BBSA/Streptavidin coated surface [1]. |
Dateline: 07/09/2000
Chemistry is one of the best developed, all encompassing and well defined fields of science today. Since ancient times, mankind has been using chemical techniques to manipulate matter on the atomic and molecular levels. As chemists improve our ability to organize atoms into atomically precise structures known as 'molecules,' fields including medicine, materials science, computer science and engineering reap the benefits. It may seem that there is little difference between the achievements of chemistry and the goals of nanotechnology, that is, to understand and manipulate molecular scale phenomena. However, nanotechnology takes a novel and revolutionary approch to this goal.
While chemistry deals with molecules in a statistical sense, nanotechnology deals with them as discrete entities, each requiring special attention. As Richard Feynman accurately predicted in 1959, 'The problems of chemistry and biology can be greatly helped if our ability to see what we are doing, and to do things on an atomic level, is ultimately developed---a development which I think cannot be avoided.' Indeed, Scanning Probe Microscopy (figure 1) has allowed sub-angstrom resolution of surfaces, leading to radical advancements in chemistry, biology and other fields.
For example, consider chemical synthesis. In Feynman's 1959 lecture, he explained, 'The chemist does a mysterious thing when he wants to make a molecule. He sees that it has got that ring, so he mixes this and that, and he shakes it, and he fiddles around. And, at the end of a difficult process, he usually does succeed in synthesizing what he wants.' Despite enormous progress in chemical methods since that time, the mixing of reagents described by Feynman is still the primary method used by synthetic chemists today. Due to the random nature of the molecular collisions in a solution, synthesis of complex (atomically precise) molecules suffers from the statistical law of entropy. Thus no reaction gives 100% yield. Furthermore, since most syntheses require multiple reactions, valuable starting materials are lost in unwanted side reactions and purification processes.
A biomimetic solution to this problem involves the idea of a molecular assembly line. Biological systems often carry out multistep reactions by passing a substrate from one enzyme to the next [2], the method used by Henry Ford to mass produce Model-T automobiles with nearly 100% yield. Molecular Manufacturing is a sub-field of nanotechnology that seeks to realize synthetic methods such as this one.
Next Page: Nanoscale Reaction Vessels
Page 1, 2, 3.
[1] This Scanning Force Microscopy (SFM) image and the vesicle images on the following pages were provided by Dr. Andreas Janshoff of the Institut fuer Biochemie, Westfaelische-Wilhelms-Universitaet Muenster Germany.
[2] Cathryn Shaw-Reid, Neil Kelleher, Heather Losey, Amy Gehring, Christian Berg, Christopher T. Walsh, "Assembly Line Enzymology by Multimodular Nonribosomal Peptide Synthetases: Catalysis of Both Elongation and Cyclolactonization by the Thioiesterase Domain of E. coli Ent F", Chem & Biol 1999 6: 385-400. Abstract.