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BP: Fachverband Biologische Physik
BP 21: Membranes and Vesicles II
BP 21.6: Talk
Tuesday, April 1, 2014, 15:15–15:30, ZEU 250
Translocation of amphiphilic polymers through lipid bilayer membranes - balanced hydrophobicity versus polarization — •Marco Werner1,2 and Jens-Uwe Sommer1,2 — 1Leibniz-Institut für Polymerforschung Dresden, Germany — 2Technische Universität Dresden, Germany
We discuss adsorption and passive translocation of amphiphilic polymers such as random copolymers [1] through a self-assembled lipid bilayer membrane. By using the bond fluctuation model with explicit solvent [2] we consider copolymers of hydrophilic and hydrophobic sites under variation of the fraction, H, of hydrophobic sites and chain length. Our results indicate a point of balanced hydrophobicity, HL=0.6, where a slight excess of hydrophobic monomers compensates an additional insertion barrier due to the self-organized packing of the bilayer. Translocation events of shorter polymers through the membrane can be observed close to the balanced condition H=HL. For longer chains, translocations are suppressed due to the "polarization" of the amphiphilic molecules with respect to the interface. Close to the point of balanced hydrophobicity, the polymer induces dynamic and static perturbations in the bilayer and increased permeability with respect to solvent. We give a more general outlook on how to design membrane active polymers with a desired emphasis on either translocation or permeabilization on the onset of balanced hydrophobicity.
[1] T. Goda, Y. Goto, und K. Ishihara, Biomaterials, 31, 2380 (2010).
[2] J.-U. Sommer, M. Werner, und V. A. Baulin, Europhys. Lett., 98, 18003 (2012)