The effect of erythrocyte associated light scattering on membrane fluorescence polarization

The apparent membrane fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene has been reported to be lower in intact erythrocytes than in isolated erythrocyte membranes. Although this difference was once suggested to be caused by the fluidizing effect associated with the loss of erythrocyte proteins during membrane isolation, it is currently thought to be an artifact resulting from intense light scattering properties of intact erythrocytes which overwhelm extrapolation methods of correcting for light scattering. This study confirmed that, at erythrocyte concentrations greater than 10(7) cells/ml, this difference was caused by intense light scattering; however, at erythrocyte concentrations less than 4.0 X 10(6) cells/ml, the anisotropy values for erythrocytes and isolated membranes are identical, demonstrating that intense light scattering can be overcome with dilute suspensions of cells.