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BP: Fachverband Biologische Physik

BP 17: Membranes and Vesicles

BP 17.3: Vortrag

Mittwoch, 7. September 2022, 15:30–15:45, H13

Buoyant adhered vesicles in finite-range membrane-substrate interactions — •Lucia Wesenberg and Marcus Müller — Georg-August University, Göttingen, Germany

Constructing switchable interlayers between soft, biological objects and hard solids is a major challenge to dynamically regulate interface interactions. Here, we focus on the adhesion of lipid vesicles on bio-inspired polymer substrates. Experiments on the adhesion of liquid droplets or vesicles on switchable surfaces often facilitate contact with the substrate by a density difference. But when compared to theoretical expectations, this key experimental characteristic as well as the finite range of the membrane-substrate interaction have mostly been neglected. Thus, we systematically studied the adhesion of axially symmetric vesicles for finite-range membrane-substrate interaction and buoyancy through simulations. We investigated the adhesion transition of vesicles in the absence of thermal fluctuations. For downward buoyancy, vesicles sediment onto the substrate and there is no mean-field adhesion transition. Whereas for upward buoyancy, adhered vesicles are metastable at best. A proper adhesion transition can only occur at zero buoyancy. Moreover, length scales such as the capillary length, extrapolation length, and curvature-decay scale exhibit a pronounced dependence on interaction range and buoyancy and should not be used uninformed. Whereas these characteristics significantly modified the adhesion diagram, the local transversality condition - relating contact curvature to adhesion strength and vesicle's bending rigidity - remains accurate in the presence of moderate buoyancy.