Advanced Imaging


Advanced Imaging Magazine

Updated: January 12th, 2011 09:49 AM CDT

Seeing Molecules With Visible Light

Superresolution microscopy allows closer look at proteins in living cells
Courtesy Travis J. Gould and Samuel T. Hess, University of Maine, Orono
Two-color superresolution imaging with FPALM reveals correlations between the fusion protein from influenza (hemagglutinin, green) and the cytoskeleton (actin, red) in fibroblast cells
University of Maine
Fluorescence photoactivation localization microscopy (FPALM) is one method that includes live-cell imaging, multicolor imaging, and 3D imaging with resolutions down to 20 nm.

By Yvonne Carts-Powell

Superresolution microscopy is a collection of recently developed techniques that use visible light to image living cells with unprecedented resolution. Even as techniques are being refined and beginning to be commercialized, researchers are using them to uncover exciting new information about processes inside our cells. And although the techniques are new, the equipment is not unusual.

(Note: superresolution microscopy is unrelated to “super resolution” image processing algorithms for refining images. The latter goes beyond the limits of the original image. Superresolution microscopy goes beyond the limits of visible light.)

Visible light microscopy is an essential tool for the life sciences, the most direct way to view cells and their nuclei, rushing blood, and other microscopic details of anatomy. Although x-ray imaging and electron microscopy can provide even finer resolution than visible light microscopy, their ionizing radiation kills or drastically alters living cells. To see living cells in action, there’s no good choice besides visible light microscopy. Fluorescence microscopy, in particular, is the popular way to study biological molecules and events.

But visible light microscopy has a major limitation: the resolution cannot get finer than about 200 nm. And there are a number of important questions in cell biology that need finer resolution. A pioneer in the field, Sam Hess of the University of Maine (Orono), says “there are many applications asking questions on the molecular length scale, such as ‘how do viral proteins interact?’’’

Another researcher in this area, Marta Fernández-Suárez of MIT and Massachusetts General Hospital, is interested in following proteins in live cells. She explains, “When people think about using microscopy to look at proteins in life sciences, they think of fixing a dead cell [on a slide] and using antibodies to probe for a particular protein. But in the last 30 years, people have tried to look at cells without having to kill them, so you can get temporal information about the protein.” Why look at proteins in living cells? Fernández-Suárez suggests few reasons:

1 2 3 4 next

Subscribe to our RSS Feeds