Quantitative measurement method based on FRAP
and FRAPa using multiphoton microscopy.
We present a new convenient method for quantitative three-dimensionally resolved diffusion measurements based on the photobleaching (FRAP
) or photoactivation (FRAPa) of a disk-shaped area by the scanning laser beam of a multiphoton microscope. Contrary to previously reported spot-photobleaching protocols, this method has the advantage of full scalability of the size of the photobleached area and thus the range of diffusion coefficients, which can be measured conveniently.