Bio-membrane pores and handles! Tuning chemical & physical properties of bio-membranes

Keywords: Bio-membranes, Pores, Membrane Curvature, liposomes

Are you interested in combining Biology, Chemistry and Physics? Then this BSc/MSc thesis might just be something you seek! This project is all about the bio-membrane and how we can tune its chemical and physical properties in such a way we can curve the membrane and create pores or handles. The classical idea about bio-membranes is that of a flat bilayer having a barrier function. However, without transport across membranes, a cell would accumulate waste products and eventually die. Furthermore, as many metabolism pathways benefit from an extensive bio-membrane surface, a single flat bilayer is not sufficient. Inside cells and organelles, bio-membranes solve these issues by curving the bilayer and forming handles and pores (Figure 1). It is an efficient method to transport large molecules across membranes, or enlarging the membrane surface, enabling a healthy cell metabolism. Furthermore, bio-membrane pores can be useful for medical applications like drug delivery. On the other hand, pores and handles could also be very destructive to the cell as it can lead to leakage and even cell death. In fact, several antibiotics target the membranes of bacteria to disrupt and create pores in the membrane. Whether it is getting a new drug delivery system, or finding alternatives for antibiotics, it starts with fundamental research of these membranes!

Schematic representation of a double membrane pore, or handle (left) and of a single membrane pore (right).
Schematic representation of a double membrane pore, or handle (left) and of a single membrane pore (right).

In this project we vary the physical properties of bio-membranes so that we can tune the curvature of biomembranes. We can do that for example by changing the phospholipid composition of the membrane, or adding surfactants that can curve the membrane. As cellular membranes are very complex, we work with model membrane systems in which we can more easily control their properties. The most simple model we work with is the liposome, this is basically an empty cell, with a much simplified cell membrane. We can look at these liposomes using Dynamic or Static Light Scattering (DLS/SLS), or Cryo-TEM (Electron microscopy). Another model membrane system we use are supported lipid bilayers (SLB) in which we create a flat membrane on top of a solid substrate. This allows us to visually check and test its surface using techniques like Atomic Force Microscopy (AFM), Reflectometry or Total Internal Reflection Fluorescence microscopy (TIRF).

As a BSc or MSc student performing a thesis in this project, you could be working on one or several aspects of this project: From preparing liposomes, to synthesizing surfactants, to membrane characterization using various techniques or to performing assays which allow us to see pore or handle formation. It is up to your interests as well!

If you are interested in an MSc/BSc thesis in this project, send me a mail. We can then further discuss the details of your project and tune it towards your interests!