FRAP (Fluorescence Recovery after Photobleaching) is the recovery of fluorescence in a defined region of a sample after a bleaching process. The FRAP effect results from the movement of unbleached fluorophores from the surrounding area into the bleached region. FRAP is used to measure the dynamics of 2D or 3D molecular mobility, e.g. in diffusion, transport or any other kind of movement of fluorescence-labeled molecules in membranes or living cells.
FLIP (Fluorescence Loss in Photobleaching) is the decrease or disappearance of fluorescence in a defined region adjacent to a repetitively bleached region. Like FRAP, FLIP is used to measure the dynamics of molecular mobility in membranes or living cells.