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Medical Definition of Fluorescence recovery after photobleaching
1. Many fluorochromes are bleached by exposure to exciting light. If, for example: the cell surface is labelled with a fluorescent probe and an area bleached by laser illumination, then the bleached patch that starts off as a dark area will gradually recover fluorescence. The recovery is due to the re population of the area by unbleached molecules and diffusion of bleached molecules to other areas. The rate and extent of recovery are a measure of the fluidity of the membrane and the proportion of labelled molecules that are free to exchange with adjacent areas. The technique is usually applied to cell surface fluidity or viscosity measurements, but is also applicable to other structures. This entry appears with permission from the Dictionary of Cell and Molecular Biology (11 Mar 2008)