Wednesday, 06/18/2003

In biological microscopy, simply being able to view a sample is half the battle. It is also crucial to capture and archive images for future reference. The SensiCamQE High Perfor-mance Digital CCD camera is the camera of choice for this task, but not all of these devices are the same. Various

microscopy applications demand cameras with appropriate technological features, such as adequate color sensitivity, speed, resolution or even physical specifications. The

SensiCamQE meets all of these performance demands.

 

Researchers use the SensiCamQE CCD camera to facilitate their study of the varying states of phospholipid bilayers that mimic cell membranes. They need to create and image

in vitro membrane models tagged with the fluorescent dye rhodamine. To capture the images, you need a camera that not only has a high sensitivity to rhodamine’s red light, but also offers the standard advantages of a CCD device. Cell membranes from different species and even different cell membranes from the same species vary in their cholesterol fractions. The phospholipids that compose these membranes tend to naturally aggregate in the more fluid state, and the greater the number of cholesterol molecules present, the more ordered the lipid bilayer. Understanding why may be paramount to understanding several membrane-based cellular processes, such as protein segregation within membranes. Researchers use fluorescence microscopy to create visual guides of these membrane

states from artificial planar membranes formed by layering phospholipid molecules on a glass microscope slide. Approximately 0.5 percent of the phospholipids are labeled with rhodamine — enough to provide a detectable fluorescence signal, but not so much that the

dye interferes with the fluidity of the membrane. Rhodamine is used because it is bright, doesn’t photobleach easily and can be covalently linked to phospholipid molecules.

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