Biophysics of cell membranes

The plasma membrane endows the mammalian cell with unique mechanical properties which, it has been recognised for many years, are essential to the functioning and survival of the cell. It is now becoming increasingly apparent that the physical properties of the membrane are also important in a much wider context, for example in the processes of signalling, transport, vesiculation, adhesion, migration, mitosis and apoptosis. The plasma membrane consists of a bilayer of phospholipids with protein inclusions which on its inner surface is covered by a network of proteins constituting the membrane cytoskeleton and on its outer surface by a dense, polyanionic glycocalyx. Our research is directed towards understanding the relationships both in normal cells and in disease. In the latter there is growing evidence of abnormalities in membrane structure and composition but little understanding of their functional significance.
Current projects involve:

• Analysis of the relationships between membrane lipid composition and rheoviscous properties.
• Characterisation of the interactions between membrane lipids and the cytoskeletal protein, spectrin.
• Investigation of the changes in the mechanical and rheological properties of blood cells in diabetes.
• Investigation of the mechanics and rheological properties of the cammelid erythrocyte.
• Characterisation of the physical properties of the endothelial cell glycocalyx.
• The development of theoretical models of membrane mechanics.
• the role of endothelial cells in mechanotransduction

In this research we employ a variety of approaches ranging from micropipette aspiration and fluctuation spectroscopy of cells and vesicles to the study of Langmuir monolayers using classical approaches, microscopy and glancing angle X-ray diffraction.