This diploma thesis focuses on the preparation and characterization of multi-chain ion pair
amphiphiles (IPAs), specifically a three-chain system composed of cetyltrimethylammonium
bromide (CTAB) and dihexadecyl phosphate (DHDP). Vesicular systems were prepared from
these IPAs in aqueous media and stabilized using various stabilizing agents. Only systems
containing phosphatidic acid were found to be stable. For these systems, the possibility of
reducing its concentration and the effect of cholesterol as a secondary stabilizing agent were
further investigated.
The prepared systems were characterized using dynamic light scattering (DLS), which provides
information on particle size and size distribution, and electrophoretic light scattering (ELS),
used to determine surface charge and colloidal stability. In addition, fluorescence spectroscopy
was employed, where generalized polarization was used to assess membrane hydration and
fluorescence anisotropy to evaluate membrane fluidity.
DLS and ELS measurements showed that systems with reduced phosphatidic acid content and
low cholesterol content do not exhibit sufficient stability, whereas the remaining systems were
stable and their sizes fell within the range suitable for potential use as drug delivery carriers.
Fluorescence measurements demonstrated a pronounced dependence of membrane properties
on temperature and cholesterol content. A membrane phase transition was detected, and it was
found that the effect of cholesterol on the organization of the lipid bilayer, its hydration, and its
fluidity varies depending on the temperature range and the corresponding phase state of the
membrane. The presence of cholesterol leads to a flatter phase-transition profile and smaller
changes in the measured parameters between individual phase states, thereby mitigating the
influence of temperature on membrane properties.