A closer look at the mega-microscopes
From medics to engineers - these days, they all want mega-microscopes. Julia Pierce takes a closer look
Wednesday 06 December 2006
Walking into the home of Titan, Britain's newest super-microscope, is an experience that takes you back in time, shrinks you to the size of a child and places you before your old school science bench. At around 15 metres high, the machine (right) dwarfs everything in the room. For an instrument that deals with the exceedingly small, this microscope is impressively large.
Buried deep within the bowels of Imperial College London, it looks like any other microscope - just 10 times bigger. At the base of the device, in front of its viewing chamber that contains the sample being examined, sits one of the department's researchers. Two screens beside him display images of the same object at different magnifications. The first screen, magnifying it around 10 million times, shows an image that looks suspiciously like frogspawn. On the second screen, magnified by 25 million times, it resembles glittering spider gossamer. I ask what patterns I'm looking at. "It's a carbon nanotube," the researcher says, waggling the sample in the chamber. Looking at the point upon which the instrument is focused I can just about make out what looks like a tiny strand of hair.
This ability to look inside materials and, more importantly, know what you are seeing, is very important. Billed as the world's most powerful commercially available microscope by its manufacturer, FEI, the Titan 80-300 allows researchers to focus a fine electron probe on a material with a diameter of less than 0.14 nanometres - that's fourteen-hundredths of one billionth of a metre. When you think a typical human hair is 80,000 nanometres in diameter, that's pretty small. This microscope lets you see how each atom behaves and why.
Carbon nanotubes are tiny cylinders of carbon about 50,000 times smaller than the width of a human hair. They have remarkable properties, including the greatest strength of any known material - twice as hard as diamond. If the way the atoms within them join together can be understood and controlled researchers may be able to produce the materials to build items such as the next generation of supercomputer.
Titan and its commercial cohorts can be bought by any lab and installed to order for £2.4m - a small price compared with the costs that would have been encountered just a few years ago. "Universities are starting to buy equipment that is now even luring key scientists back from the States," adds Pete Lander, assistant general manager at JEOL (UK). "Two world-class scientists recently came over to work at York from the US. They said they wanted to work on a powerful microscope but the only way to get funds to do this was to come back to the UK."
There is only one such Titan in Britain, and it is also the only microscope in Britain - and one of only a handful in the world - featuring a monochromator. Basically, this is the bit that tells you what sort of atom you are looking at. "Imagine the cover of Pink Floyd's Dark Side of the Moon," says Dr David McComb, reader in materials characterisation at Imperial's department of materials. "If you put white light through a glass prism it splits into different colours. Add a filter and you can pick a colour and single it out to work with." In the Titan, the monochromator takes the place of the prism, so you can pick out electrons with a particular energy range to hit the sample. The energy of the electrons changes when they hit the sample. Measuring that change tells you what has been in their way.
Such equipment is also vulnerable. Imperial spent a further £500,000 on the room that houses Titan. Systems control temperature fluctuations to within 0.2 degrees. It is also shielded to minimise vibration and eliminate stray magnetic fields. "I can't think of any other large microscope that's been placed in a big city," says McComb.
Imperial College is already looking into common diseases and it has earmarked this as one of Titan's first projects. Patients suffering from degenerative brain diseases process iron abnormally, leaving iron nanoparticles in their brain tissue. Discovering how iron atoms affect the tissue surrounding them could allow the development of new treatments to delay or even halt these conditions. Observing the way in which atoms stray from one material to another during fuel cell operation could also help scientists design longer-lasting versions to power pollution-free buses, trains and cars.
Rival manufacturers, however, are keen to stress that better things are on the way. Several goals remain, such as the ability to view atoms in 3D in live biological material. This would allow researchers to see exactly what happens to the very basic tissue of a human organ the second it is hit by a chemical, increasing their understanding of why some drugs work and some don't.
"Competition is good," adds Paul Ansell, electron microscope sales and marketing manager at Hitachi High-Technologies, which has just installed one of its latest models at the University of Surrey. "It means researchers can now have the choice to select a laboratory offering exactly what they need."
Leaving Titan and stepping out on to the street, it's hard to believe so much amazing science is hidden beneath my feet. But not quite as astonishing as the patterns revealed in that nanotube.
See the big picture
If you haven't got £2.4m to spare this Christmas, what can you buy on a more reasonable budget and, more importantly, what will your new toy let you see?
At £8, the Early Learning Centre's Zoom Microscope isn't exactly top of the range, but by magnifying objects by up to 100 times, it might inspire under-10s to look more closely at their world.
The University of Cambridge's pretty basic Precision Microscope (£34.99) gives you up to x300 magnification and comes with a list of experiments.
£71.99 buys the Digital Blue QX5 Digital Microscope. This magnifies objects by up to 200 times, which you can view on your PC. You can take photos of your samples and turn them into posters or e-mail them to friends.
For £89.95 plus an extra £95 for a computer connection you can buy a real scientific instrument. The RM1 provides up to x600 magnification. It comes with a gruesome pack that includes a rat flea, liver fluke and various types of animal bloods.
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