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"There's Plenty of Room at the Bottom" was the title of a lecture given by US physicist Richard Feynman 1959 before the American Physical Society in Los Angeles. In it, he described the possibilities that would be opened up – given the laws of physics – if scientists and engineers were able to work at the atomic level. One of his visions was that machines could be inserted into human blood vessels to repair damage to internal organs – like tiny surgeons.
A key technology of the 21st century
Over the past 20 years, Feynman's vision of the future has evolved to become an important field of research: nanotechnology. Scientists are studying the properties and functions that materials exhibit when they take the form of particles up to one hundred nanometres in size. One nanometre equals a millionth of a millimetre – by way of comparison, a human hair is roughly fifty thousand times thicker. The properties of particles at the nano level change hugely in some cases: for example, nanoparticles have a much larger surface area as compared with their volume, which makes them considerably more chemically reactive. Characteristics such as translucence, electrical conductivity and mechanical stability also differ from those of larger particles.
In Germany, more than 700 university departments and research institutions are currently pursuing research in this area, more than half of them in materials research. "Ever since the boom in the early 2000s, when people expected nanotechnology to spawn an industry worth trillions, a somewhat more sober view has been taken", explains Professor Rüdiger Iden, a former vice president of the chemicals company BASF and an advisor and member of Germany's National Academy of Science and Engineering. He has been closely monitoring the developments from the start. These days, the nano hype has been replaced by a more realistic appraisal of its possibilities.
Miraculous materials on the nano scale
Carbon nanotubes were long regarded as the miraculous materials of the nano world: They are tiny tubes with a diameter of 1 to 50 nanometres comprising carbon atoms in a honeycomb structure. Despite their low weight they are more stable than steel and conduct electricity particularly well. However, it is difficult to use this material in industrial applications due to the risk of it losing valuable properties when processed.
One method of processing nanotubes without changing their molecular structure has been developed by the Functional Nanomaterials Chair at Kiel University (CAU) in cooperation with colleagues from the University of Trento. The researchers dilute carbon nanotubes with water and allow them to drip into the pores of a ceramic scaffolding, where they self-entangle to form a felt-like coating around the ceramic core. This makes the ceramic structure around 100,000 times more stable. The nanotube scaffolding can be used in a wide range of applications – from batteries and electronic components to medical technology.
Nano machines for medical purposes
Rüdiger Iden believes that the future of nanotechnology lies first and foremost in biomedical applications, however – such as those being studied by Veronika Magdanz at the Chair of Applied Zoology at TU Dresden. A biotechnologist, Magdanz has machines in mind that come very close to Feynman's 1959 vision: diagnostic and therapy tools made of smart materials on the nano scale that "ride piggyback" on sperm through the vessels of the body. Magdanz's idea is that such "swimming microrobots" could in the future help detect anomalies inside the body and transport drugs directly to the site of the disease – e.g. cancer drugs could be delivered straight to a tumour. She has already achieved this with cell cultures in a Petri dish.
"The nano scale is the scale of life", is how Rüdiger Iden sums up the situation with respect to cells and their elementary building blocks such as DNA and RNA molecules which, with a diameter of just a few nanometres, are exactly on this scale. This is both a blessing and a curse: thanks to their tiny dimensions, artificial nanoparticles can be used to produce carbon nanotubes or to penetrate deep into the human organism through the respiratory channels or digestive tract. And this is also precisely why scientists are keeping a very close eye on any risks posed by nanotechnology.
Kiel Nano, Surface and Interface Science (KiNSIS)
Expertise in many disciplines is needed to understand the properties of nano structures and translate them into practical applications. This is why researchers at or affiliated with universities in Germany have teamed up in interdisciplinary networks. For example, more than 80 chemists, physicists, engineers and life sciences working groups belong to Kiel University’s Kiel Nano, Surface and Interface Science (KiNSIS) network. KiNSIS cooperates with other research institutions, engaging in scientific exchange and fostering young researchers.www.kinsis.uni-kiel.de