Bachelor Thesis Defence: Christoffer Dam Florentsen

Title: The Effect of Curvature on Liposome ζ-potential

Abstract:

Liposomes have a wide variety of practical applications within medicine and immunology. A thorough characterization of liposome stability and understanding of the mechanisms governing fusion, delivery and binding of proteins or drugs, is important.

Here we have investigated the curvature dependency of liposome ζ-potentials. The measurements were carried out on three different kinds of liposomes; (i) zwitterionic DOPC liposomes, (ii) negatively charged DOPS liposomes and (iii) brain liposomes. Measurements of ζ-potentials were related to particle size by dynamic light scattering (DLS). We demonstrate that the ζ-potential of DOPC liposomes is curvature dependent, and that inclusion of acidic lipids can affect this tendency.

Electrostatic interactions are known to be one of the key modes in protein recruitment to lipid membranes. Changes in the electrostatic environment close to membrane are hence of great importance. Consequently, we believe that our findings are of biological significance and that electrostatics could be yet another parameter that membrane curvature is used to modulate within cells.

Supervisor: PhD student Andreas Lauge Christensen (alauge@nano.ku.dk), Jannik Larsen (jkl.nano@gmail.com) and Prof Dimitrios Stamou (stamou@nano.ku.dk) “Bionanotechnology and Nanomedicine Laboratory, Department of Chemistry and The Nano Science Center, Copenhagen University

Censor Prof. Thomas Lars Andresen, Department of Micro- and Nanotechnology, DTU, Denmark