title: Partitioning behavior of indocarbocyanine probes between coexisting gel and fluid phases in model membranes.
abstract: Gel-fluid partition coefficients, Kp, were measured for a series of indocarbocyanine dyes in multilamellar lipid vesicles. The dyes examined had alkyl chain lengths from 12 to 22 carbons. Fluorescence quenching by a spin-labeled phosphatidylcholine-enriched fluid phase created a large difference in quantum yield for indocarbocyanine fluorescence between fluid and gel phases, enabling reliable Kp determinations. The values range from Kp = 8 for the 12-carbon chain, favoring a fluid phase over a Ca2-phosphatidylserine rigid phase, to Kp = 0.02 for the 20-carbon chain dye, favoring a distearoylphosphatidylcholine-rich gel phase over the fluid phase.
authors.affiliation: Department of Chemistry, SUNY-Cortland 13045.
authors.forename: C H
authors.initials: CH
authors.lastname: Spink
authors.forename: M D
authors.initials: MD
authors.lastname: Yeager
authors.forename: G W
authors.initials: GW
authors.lastname: Feigenson
mesh_terms: D002232:Carbocyanines; D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D008856:Microscopy, Fluorescence; D010713:Phosphatidylcholines; D011804:Quinolines
chemical_list: D002232:Carbocyanines; D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D011804:Quinolines