Incorporation of dyes into low density lipoprotein in the presence of non-ionic surfactants.

The interaction of low density lipoprotein (LDL) with two model dyes in the presence or absence of non-ionic surfactants has been studied. The water soluble dye, thymol blue, only weakly interacts with LDL to cause slight increases in particle size and the interaction can be reversed on column chromatography and dialysis. The oil-soluble dye sudan III reacts strongly with LDL to produce marked changes in particle size the complex formed being stable to dialysis and gel exclusion chromatography. These interactions are not affected by the presence of surfactants. The results indicate that even small quantities of lipophilic materials will easily partition into the particle, with or without the aid of surfactants and can have a marked effect on the measured size of the particle.