Membrane biophysics

Model membranes, in the form of lipid bilayers – major examples being giant unilamellar vesicles (GUVs) and supported lipid bilayers (SLB) – have long served as idealised cell membranes and have been studied in detail in order to infer properties of the cell membrane, which was deemed to be too complex for clean experiments. Over the years, complexity has been added to simple lipid membranes to mimic the cell membrane better. The physics of model membranes is well known and the paradigm of Helfric elastic energy and hydrodynamics has been verified in countless experiments. The current challenge is to determine how best to move from quantitative understanding of model membranes to biological membranes with their full complexity.

Immunobiophysics

T Lymphocytes are able to discriminate self- and foreign- protein fragments (antigen) quickly and with astonishing precision, sensitivity and robustness. How, starting from a single bond between their special receptors (TCR) and an antigen, they can activate the whole cell and eventually the whole organism, remains one of the central mysteries in immunology. It is believed that modulation of its 3D topography coupled to its molecular reorganisation via clustering of TCR and/or formation of membrane-proximal condensates plays an important role. We combine nanobiotechnology to manipulate the cell, and dynamic optical super-resolution techniques to image it. We ask how the adhesion of an immune-cell to a surface mimicking a target cell impacts its mechanics and activity.