title: Droplet shape analysis and permeability studies in droplet lipid bilayers.
abstract: We apply optical manipulation to prepare lipid bilayers between pairs of water droplets immersed in an oil matrix. These droplet pairs have a well-defined geometry allowing the use of droplet shape analysis to perform quantitative studies of the dynamics during bilayer formation and to determine time-dependent values for the droplet volumes, bilayer radius, bilayer contact angle, and droplet center-line approach velocity. During bilayer formation, the contact angle rises steadily to an equilibrium value determined by the bilayer adhesion energy. When there is a salt concentration imbalance between droplets, there is a measurable change in the droplet volume. We present an analytical expression for this volume change and use this expression to calculate the bilayer permeability to water.
authors.affiliation: Molecular Physics Laboratory, SRI International, Menlo Park, California 94025, USA.
authors.forename: Sanhita S
authors.initials: SS
authors.lastname: Dixit
authors.forename: Alexandra
authors.initials: A
authors.lastname: Pincus
authors.forename: Bin
authors.initials: B
authors.lastname: Guo
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Faris
mesh_terms: D008051:Lipid Bilayers / Q000737:chemistry*; D010539:Permeability; D014867:Water / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D014867:Water