PhD Defense Casper van der Wel: 'Lipid mediated colloidal interactions'



16:15 hrs


Rapenburg 73. Leiden


The lipid membrane is a basic structural component of all living cells. Embedded in this nanometer-thin barrier, membrane proteins shape the membrane and at the same time respond to the shape of the membrane. This two-way interaction gives rise to a force between membrane-deforming objects that is mediated by the membrane. In this thesis, this effect is measured by employing micron-sized colloidal particles. In Chapters 2 and 3, methods for extracting local forces from video images of colloidal particles are described. Then, in Chapter 4, the development of colloidal particles that strongly attach to specific lipid membranes is described. These are then used in Chapters 5 and 6, in which membrane-mediated forces and assembly pathways between membrane-attached colloidal particles are investigated and quantified. Finally, in Chapters 7 and 8, the preparation of micron-sized oil droplets is studied and their use as lipid monolayer support is demonstrated. The results from this thesis contribute to fundamental microbiological questions about forces between membrane proteins, as well as to the understanding of the toxicity of microplastics.