title: Soft pinning of liquid domains on topographical hemispherical caps.
abstract: The role of lipid composition as a regulator or mediator of processes that take place in biological membranes is a very topical question, and important insights can be gained by studying in vitro model lipid mixture systems. A particular question is the coupling of local curvature to the local phases in membranes of mixed composition. Working with an experimental system of giant unilamellar vesicles of ternary composition, the curvature is imposed by approaching the membrane to a topographically (on the micron scale) patterned surface. Performing experiments, we show that domains of the more disordered phase localise preferentially to regions of higher curvature. We characterise and discuss the strength of this "caging" behaviour. In future, the setup we discuss here could prove useful as a platform to localise domains rich in membrane proteins, or to promote the onset of biochemical processes at specific locations. Finally, we note that the methods developed here could have also applications in bio-sensing, as a similar but metal coated topography can sustain plasmonic resonances.
authors.affiliation: Dipartimento di Fisica e Scienze della Terra "Macedonio Melloni", Università di Parma, Viale Usberti 7/A, 43124 Parma, Italy; Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge, UK.
authors.forename: Luigi
authors.initials: L
authors.lastname: Feriani
authors.affiliation: Dipartimento di Fisica e Scienze della Terra "Macedonio Melloni", Università di Parma, Viale Usberti 7/A, 43124 Parma, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Cristofolini
authors.affiliation: Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge, UK. Electronic address: pc245@cam.ac.uk.
authors.forename: Pietro
authors.initials: P
authors.lastname: Cicuta
mesh_terms: D001696:Biomechanical Phenomena; D002462:Cell Membrane / Q000737:chemistry*; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D008958:Models, Molecular; D013499:Surface Properties
chemical_list: D004129:Dimethylpolysiloxanes; D008051:Lipid Bilayers; C013830:baysilon
keywords: Membrane curvature; Membrane domains; Phase separation; Topographical pinning