Time-resolved fluorescence depolarization of rhodamine B and octadecylrhodamine B in Triton X-100 micelles and Aerosol OT reversed micelles.

J. Phys. Chem. 92 (1988) 759-765 01/1988; 92(3).
Source: OAI

ABSTRACT Time-resolved fluorescence and fluorescence anisotropy experiments were conducted on rhodamine B and octadecylrhodamine B incorporated into aqueous Triton X-100 micelles and in sodium bis(2-ethylhexyl) sulfosuccinate entrapped water or glycerol in a hydrocarbon solvent (heptane or dodecane). The time-resolved fluorescence behavior of the dye molecules in the micellar media was compared with that of the dye in homogeneous solution, from which a qualitative estimate of the polarity of the probe environment in the micelles could be inferred. The anisotropy decay of the fluorescent probes was analyzed with a biexponential decay model yielding correlation times characteristic for overall and internal micellar motion. The overall micellar rotation could be clearly distinguished from the faster internal motion in small water droplets and in glycerol droplets in heptane, for which there is good agreement between calculated and observed micellar rotation times. The hydrodynamic radii of glycerol droplets in dodecane medium are larger than the corresponding radii of droplets in heptane.

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    • "All other conditions are as in Fig. 2. See ''Materials and methods'' for other details problems in biology including their application as reaction media (Khmelnitsky et al. 1989; Carvalho and Cabral 2000) and in protein biotechnology (Melo et al. 2001). They offer certain inherent advantages in fluorescence studies over membranes since reverse micelles are smaller and optically transparent, have well-defined sizes, and are relatively scatter-free (Laane and Visser 1987; Visser et al. 1988). Reverse micelles represent a type of organized molecular assembly which offers the unique advantage of monitoring dynamics of molecules with varying states of hydration that is difficult to achieve with complex systems such as membranes. "
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