Fluorescence photobleaching recovery techniques for translational and slow rotational diffusion in solution and on cell surfaces.

Fluorescence photobleaching recovery techniques allow the accurate quantification of lateral and rotational motions of small numbers of specific molecules in complex systems. The technique was first applied to the study of translational diffusion in cell plasma membranes (Peters et al., 1974). This continues to be the principal area of application. More recently, it has been extended to the study of macromolecular diffusion, binding and polymerization in solution (e.g Barisas & Leuther, 1979; Lanni et al., 1981; Icenogle & Elson, 1983), and in situ, in the cytoplasm of living cells (e.g. Wojcieszyn et al., 1981; Wang et af . , 1982; Salmon et al., 1984). Fluorescence photobleaching analysis of slow rotational motion has generated considerable theoretical interest (e.g. Koppel, 1983; Wegener & Rigler, 1984; Wegener, 1984) but few experimental results to date (Johnson & Garland, 1981; Smith et af . , 1981; Jovin, 1986). Features and capabilities of the technique, emphasizing the analysis of translational diffusion, will be illustrated in this report with recent data from mammalian sperm cells and erythrocyte membranes.