Interaction and Complex Between Phospholipid and Pluronic
Yu Yuan Chieng and Shing Bor Chen. Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117576, Singapore
Interaction between phospholipid vesicles and pluronic F-127 with varying concentration was investigated using Dynamic Light Scattering (DLS) and Differential Scanning Calorimetry (DSC) characterization. Rheological behavior of the mixed system at high concentration of pluronic has also been examined and discussed in detail. The coexistence of vesicles with different states of pluronic in aqueous solution (unimer state, micelle state and soft gel state) exhibits interesting four main stages of interaction mechanism when the pluronic concentration is progressively increased. Results reveal that pluronic monomers are incorporated into vesicles bilayer system at low concentration; the pluronic micelles disturb and solubilize vesicles when the critical micellization concentration is reached; then mixed micelles form at higher concentrations, and finally these mixed micelles rearrange themselves into a complex microstructure with higher stability and thermosensitivity. In addition, the increase in viscosity and viscoelastic properties of the mixed micelles compared to vesicles and pluronic alone also suggests that there is a strong interaction between the two species. There is also evidence showing the restoration of phospholipids structural integrity with a broadened endothermic peak for the lipid main phase transition under the pluronic soft gel state condition. These findings encourage a potential development for self-assembled amphiphilic systems with additional functionality for advanced applications.