Photobleached Fluorescence

Szabo, G., Pine, P., Weaver, J., Kasari, M. and Aszalos, A. (1992). Epitope mapping by photobleaching fluorescence resonance energy transfer measurements using a laser scanning microscope system. Biophys. J. 61, 661-70. 

Patel, R. C., Lange, D. C. and Patel, Y. C. (2002). Photobleaching fluorescence resonance energy transfer reveals ligand-induced oligomer formation of human somatostatin receptor subtypes. Methods 27, 340-8. 

FIGURE 3.12 Simulation (left column) and photobleached-fluorescence visualization (right column) of an analyte band traveling around a constant-radius corner. In both cases the channel is 250 pm wide. In the experiments, the channels were - 40 pm deep [535]. Reprinted with permission from the American Chemical Society. 

Unambiguous determination of the conditions under which slippage occurs requires a technique able to measure the velocity of the fluid in the immediate vicinity of the solid wall over a thickness comparable to the size of a polymer chain, i.e. a few tens of nanometers. Classical laser Doppler velocimetry does not meet this requirement even if it allows for the determination of velocity profiles which clearly reveal a non-zero velocity within typically a few 10 pm from the wall. We have developed a new optical technique. Near Field Velocimetry (N.F.V.) [14], which combines Evanescent Wave Induced Fluorescence (E.WF.) [27] and Fringe Pattern Fluorescence Recovery After Photobleaching (F.P.F.R.A.P.) [28]. The former technique gives the spatial resolution normal to the solid wall, while the latter one enables the determination of the local velocity of the fluid. A major constraint of the technique is that it needs polymer molecules labelled with an easily photobleachable fluorescent probe. 

The fluidity of LB monolayers on solid supports was characterized by measuring the long-range (> 10 xm) translational diffusion of dissolved fluorescent lipids using fluorescence pattern photobleaching recovery (FPPR). In this technique, an area of the membrane is illuminated with a spatially striped intensity. After irreversibly photobleaching, fluorescence recovery occurs, as unbleached molecules from nonilluminated stripes move into the illuminated stripes . In fluid-like LB films, translational diffusion coefficients... 

Key words DictyosteHum, Photobleaching, Fluorescent proteins, FRAP, PTEN, PTC... 

Mosier B, MoUio J, Santiago J (2002) Photobleached-fluorescence imaging of microflows. Exp Fluid 33(4) 545-554... 

Flow profiling Flow tagging Laser-induced molecular tagging Laser-induced photochemical anemometiy Photo-activated nonintrusive tracking of molecular motion Photobleached fluorescence... 

Fig. 3 Photobleached fluorescence-based molecular tagging and visualization.

Key words Optical patterning, Proteins, Photobleaching, Fluorescence-tagged molecules. Laser-... 

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