Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 35: Membranes and vesicles II (joint BP/CPP)

BP 35.12: Talk

Wednesday, March 18, 2015, 18:15–18:30, H 1028

The interaction of patterned amphiphilic dendritic nanomaterial with a lipid-monolayer — •M.Alejandra Sanchez, Katharina Bücher, Klaus Müllen, Mischa Bonn, and Ellen H.G Backus — Max Planck Institute for Polymer Research, Mainz, Germany

Well-defined amphiphilic dendrimeric macromolecules are biomimetic nanomaterials that can be used for drug delivery into cells. By organic synthesis, functional groups can be positioned in an atomically defined way, resulting in alternating patches of polar and apolar nature. Here we study systematically the interaction of various dendrimers with a model membrane consisting of a self-assembled monolayer of the lipid DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) on water. By using sum frequency generation spectroscopy we obtain molecular specific information about the membrane molecules and the water molecules in the vicinity of the lipid. Although the dendrimers are not surface-active at the bare water-air interface, they do interact strongly with the lipid monolayer. The presence of dendrimers in the solution below the monolayer causes changes in the water orientation as well as the alignment of the lipid molecules. Remarkably, details of the interaction depend on the surface groups present on the dendrimer. Very small changes (e.g. n-propyl vs iso-propyl) result in a different behavior. We link the molecular level picture with the efficiency of penetrating into the cells.