Berlin 2024 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 4: Interfaces and Thin Films

CPP 4.10: Vortrag

Montag, 18. März 2024, 12:00–12:15, H 0111

Spiralling Hierarchal Structures in Chiral Lipid Monolayers Mapped with SFG Microscopy — •Alexander Fellows, Ben John, Martin Wolf, and Martin Thämer — Fritz-Haber-Institut der MPG, Berlin, Germany

The importance of phospholipids cannot be overstated. Their amphiphilic nature promotes self-assembly into two-dimensional membranes in which the hydrophobic tails tightly pack and point away from the membrane interface. Beyond this well-defined out-of-plane structure, the specific in-plane molecular arrangement also has profound implications in a vast range of physiological processes. Studies of model systems have shown condensed lipid islands (rafts) to form with a wide range of sizes and morphologies. Whilst there has been some suggestion that these domains possess in-plane molecular anisotropy and mesoscopic structural chirality, the details of their in-plane molecular orientations nevertheless remain largely unknown.

Here, we employ a newly developed SFG microscope with a novel imaging system to investigate the condensed lipid domains within monolayers with mixed chirality. We find that the domains possess curved in-plane molecular directionality within a spiralling mesoscopic hierarchal packing structure. By comparing different enantiomeric mixtures, both the molecular and spiral turning directions are shown to depend on the chirality, but with a clear deviation from mirror symmetry in the formed structures. This demonstrates strong enantioselectivity in the domain growth process, with potential connections to the evolution of homochirality in all living organisms.

Keywords: Lipid Monolayer; SFG Microscopy; Cell Membrane; Molecular Imaging