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The Big and the Small of It

Almost everyone has marveled at those wonderful pictures from the Hubbell Telescope. Astronomers are looking deeper and deeper into space and subsequently farther back in time. Many sensational computer improvements have, at the same time, been made to our terrestrial telescopes. These are indeed exciting times for the astronomers.

What is less well known is that cell biologists are all drooling over the newest microscopes. The new laser scanning Confocal microscope not only rejects out-of-focus light but also can actually scan below the surface. I have seen pictures made by one of these confocals and they are sensational.

A disadvantage of the confocal is that it must pass a raster scanning laser beam through the entire specimen. Because of the time needed to scan the laser beam (sometimes up to a minute) it bleaches above and below the focal plane as it excites the pixels in the specimen. The Two-Photon Microscope uses an ultra fast pulsed laser beam with 2 red photons, which are absorbed by a fluorochrome. The advantage is its effect is limited only to the section being studied without bleaching the whole thing.

Even more exciting to me is the development of the MRI microscope, which will be able to achieve single-cell spatial resolutions in three dimensions from living specimens up to 2.5cm by 5cm.

Another advance in microscopes is a High Resolution Three Dimensional light microscope from Edge Scientific, with true three-dimensional imaging which is most striking in living specimens, whole mounted tissues or thick sections. Another advantage is you can photograph the specimens using conventional Zeiss objectives (10x to 100x).

Another exciting field is Video Microscopy. Computer enhanced video microscopy can film in real-time and has several advantages ranging from increased light-sensitivity to improved resolution. The microscope uses a SIT low-light level video camera. Output is in computer files to be viewed later.

Also Roger Tsien has developed an ever-growing family of indicator dyes for intercellular messengers. The BIR center has put together a Ratio-metric microscope and developed software which will calculate of two different video images at 30 frames per second. Again, the output is in computer files.

If you are as rich as Bill Gates you can buy all these microscopes or you can get on the Biological Imaging Resource CenterÕs sign-up list and use some of them. One price tag I saw in the Rice University News was a Zeiss confocal for only $440,000. (The above information taken from a Biological Imaging Resource Center page by Scott Fraser and Russ Jacobs). For more details and perhaps accuracy, go to the Beckman Institute Catalog of Centers and Facilities.