Fluorescent Probes for Lifetime and Anisotropy Studies

The choice of fluorophore for studying membrane properties is governed by a number of requirements. Some of these have been discussed previously,(66) The main points (mainly with reference to anisotropy) are  

The fluorophore should be well characterized in terms of absorption and emission transition moments, quantum yield, polarization bands of interest, and behavior at different temperatures. The quantum yield should be high enough so that the level of probe needed for acceptably low signal noise would not be great enough to cause significant perturbation effects. 

The scale of the fluorescence lifetime should coincide with the time scale of the physical process of interest. 

For lipid dynamics studies, the probe should be rigid, preferably rod- or disk-shaped with at least biaxial symmetry so that information on order can be obtained. 

The partitioning into the membrane should be high in combination with a low solubility/fluorescence in water. 

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