title: Formation of supported lipid bilayers on silica particles studied using flow cytometry.
abstract: Silica colloidal particles with functionalized surfaces are used, for example, in studies of membrane proteins or for drug delivery, where novel applications are based on the use of particles covered by lipid membrane bilayers. The mechanism by which such supported lipid bilayers are formed on spherical support is not fully understood. Here, we present results from studies of this process using a new method based on flow cytometry. The approach enabled us to detect particle populations coated and uncoated with lipids in the same sample according to the vesicle:particle surface area ratio. The data suggest that DOPC lipid vesicles efficiently break upon interaction with the silica colloidal particle surface; only a small fraction of the adsorbed vesicles remain unbroken. Furthermore, the data support earlier observations showing that formation of the lipid bilayer at the surface is a cooperative process, where bilayer formation is catalyzed by previously bound membrane fragments.
authors.affiliation: Department of Biochemistry and Biophysics, Centre for Biomembrane Research, Stockholm University, SE-10691 Stockholm, Sweden.
authors.forename: Gustav
authors.initials: G
authors.lastname: Nordlund
authors.forename: Rosa
authors.initials: R
authors.lastname: Lönneborg
authors.forename: Peter
authors.initials: P
authors.lastname: Brzezinski
mesh_terms: D000327:Adsorption; D000818:Animals; D002384:Catalysis; D002462:Cell Membrane / Q000378:metabolism; D003102:Colloids / Q000737:chemistry; D005434:Flow Cytometry / Q000379:methods*; D005456:Fluorescent Dyes / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008051:Lipid Bilayers / Q000737:chemistry*; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry; D012542:Scattering, Radiation; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D003102:Colloids; D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D012822:Silicon Dioxide; C017251:1,2-oleoylphosphatidylcholine