HYDROPHOBIC NANODOMAINS IN HYALURONAN-SURFACTANT SYSTEM: A FLUORESCENCE ANISOTROPY STUDY

This paper deals with the fluorescence anisotropy study of hydrophobic nanodomains formed by interaction between hyaluronan (Hya) and cationic surfactant cetyltrimethylammonium bromide (CTAB) below critical micelle concentration in aqueous solution and the effect of sodium chloride addition to this system. Hyaluronan as negatively charged polyelectrolyte can interact with cationic surfactants via electrostatic interactions to form aggregates, which could be potential used for targeted drug delivery. Two fluorescent probes, which are solubilized in hydrophobic region, were used - perylene and diphenylhexatrien (DPH). The emission spectra, total intensity of fluorescence and steady-state anisotropy of fluorescence in the samples were measured. It was observed that initial addition of CTAB to hyaluronan aqueous solution leads to forming some small hydrophobic domains linked to hyaluronan chains. Then an increasing concentration of CTAB causes phase separation and formation of a condensed phase. Addition of sodium chloride to the samples leads to reorganization of this system - the condensed phase is dissolved and probably free micelles (possibly mixture of micelle linked to hyaluronan chain with free micelle) are formed in the solution.