Supervisors info:
Κ.Δεμέτζος Καθηγ.(Επιβλέπων), Σ.Πίσπας Κύριος Ερευνητής, Μ.Δανέζης Επικ. Καθηγ,
Summary:
The present study deals with the physicochemical characterization of
Dipalmitoylphosphatidylcholine (DPPC) liposomes and DPPC: cholesterol (chol)
(9:1 molar ratio) liposomes, and the determination of their fractal dimension,
in an aqueous and in a biological medium. Dynamic, static and electrophoretic
light scattering and fluorescence spectroscopy are used as experimental
techniques to elucidate the structure and physicochemical parameters of
liposomes in an ageing study in two different media, as well as their
structural response in changes in concentration and temperature. The extended
DLVO theory would be the tool to explain the phenomenology of the colloidal
behavior in these systems and of their aggregation process. The fractal
dimensionality of DPPC liposomes decreased while for DPPC: cholesterol (9:1) it
remained unaffected in the two dispersion media. The structure of the liposomal
systems, the process kinetics, and the fractal dimension are consistent with
the Diffusion-Limited Cluster Aggregation (DLCA) and Reaction-Limited Cluster
Aggregation (RLCA) models. On the contrary, hydrodynamic radius (Rh) was found
to be stable during the variations of colloidal system conditions, especially
due to concentration changes. Finally, we suggest that this study can be a
rational road map to design advanced Drug Delivery nano Systems (aDDnSs) with
improved pharmacokinetic profile which could be considered as crucial for their
effectiveness.
Keywords:
Fractal dimension, Nanotechnology, Liposomes, Colloidal systems, Fractal Geometry