Dresden 2014 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 4: Membranes and Vesicles I

BP 4.5: Vortrag

Montag, 31. März 2014, 16:15–16:30, HÜL 386

Induced phagocytic particle uptake into a giant unilamellar vesicle using optical tweezers — Andreas Meinel, Benjamin Tränkle, and •Alexander Rohrbach — University of Freiburg, Georges-Köhler-Allee 102, 79110 Freiburg

Phagocytosis, the uptake and ingestion of solid particles into living cells, is a central mechanism of our immune system. Due to the complexity of the uptake mechanism, the different forces involved in this process are only partly understood. Therefore the usage of a Giant Unilamellar Vesicle (GUV) as the simplest biomimetic model for a cell allows to investigate the influence of the lipid membrane on the energetics of the uptake process. Here, we use a photonic force microscope (PFM) to approach an optically trapped 1 um latex bead to a immobilized GUV to finally insert the particle into the GUV. By analysing the mean displacement and the position fluctuations of the trapped particle during the uptake process in 3D with nanometre precision, we are able to record force and energy profiles, as well as changes in the viscous drag and the stiffness. The measured energy profiles, which are compared to a Helfrich energy model for local and global deformation, show a good coincidence with the theoretical results.