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Chemistry in Focus 3rd edition Tro Chapter 19 Nanotechnology Out of SciFi; Into the Lab • Five atoms, end to end, measure a nanometer (10-9 m). • Human hair measures 20,000 nm in diameter. • Can we make a machine so tiny is could navigate the bloodstream? • Nature has already done this. • Some see nanotechnology as bioimitation. Scanning Tunneling Microscope • 1981 Binnig and Rohrer measuring electrical conductivity over a surface • Noticed bumps in their measurements which have been interpreted as individual atoms • Modern STMs scan surfaces of interest with atomically fine metallic tips. • We can not only image atoms, but move them Atomic Visibility • STM made the atomic world visible for the first time. • Premier tool for scientists developing nanotechnology • Binnig and Rohrer were awarded the 1986 Nobel Prize in physics for this work. Atomic Force Microscope • STM can image only metallic surfaces • AFM (atomic force microscopy) can image nonmetallic surfaces • AFM tracks the movement of a laser reflected off the back of a cantilever • Tapping AFM can image biological samples Buckyballs • Graphite – carbon atoms in layered sheets • Diamond – three-dimensional honeycomb • Buckyballs – 60 carbon atoms bonded into a hollow sphere – Smalley, Curl, Kroto awarded the 1996 Nobel Prize in chemistry – Named for R. Buckminster Fuller, American architect of geodesic designs resembling C60 Nanotubes • 1991 marks the birth of the buckytube – Shape is tubular instead of spherical • A few atoms in diameter but kilometers in length – Strong as steel – Can be made electrically conducting Weighing and Writing with Atoms Conducting Electricity with Nanotubes • Tiny electric circuits may allow – Flat-panel displays – Water desalination – Flexible, foldable monitor displays Nanomedicine • Doctors can encase foreign cells so that the body will not reject them. – Pancreatic animal cells can be introduced into a human diabetic patient. Artificial Cells and Nanorobots • Can we construct nanomachines that mimic living cells? • Can we construct nanorobots that can do work within biological systems? • Current work involves targeted drug delivery – Protection of healthy cells from chemo drugs – Concentrated delivery of toxins to cancerous tissue Nanoproblems • Can nanotechnology visionaries go to far? • How will the ethics of such power be handled?
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