title: Size-dependent ultrafast structural dynamics inside phospholipid vesicle bilayers measured with 2D IR vibrational echoes.
abstract: The ultrafast structural dynamics inside the bilayers of dilauroylphosphatidylcholine (DLPC) and dipalmitoylphosphatidylcholine vesicles with 70, 90, and 125 nm diameters were directly measured with 2D IR vibrational echo spectroscopy. The antisymmetric CO stretch of tungsten hexacarbonyl was used as a vibrational probe and provided information on spectral diffusion (structural dynamics) in the alkyl region of the bilayers. Although the CO stretch absorption spectra remain the same, the interior structural dynamics become faster as the size of the vesicles decrease, with the size dependence greater for dipalmitoylphosphatidylcholine than for DLPC. As DLPC vesicles become larger, the interior dynamics approach those of the planar bilayer.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA 94305.
authors.forename: Oksana
authors.initials: O
authors.lastname: Kel
authors.forename: Amr
authors.initials: A
authors.lastname: Tamimi
authors.forename: Michael D
authors.initials: MD
authors.lastname: Fayer
mesh_terms: D008027:Light; D008051:Lipid Bilayers / Q000737:chemistry*; D008567:Membranes, Artificial; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D012542:Scattering, Radiation; D012997:Solvents / Q000737:chemistry; D013055:Spectrophotometry, Infrared / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013696:Temperature
chemical_list: D008051:Lipid Bilayers; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D010743:Phospholipids; D012997:Solvents; C002448:1,2-linoleoylphosphatidylcholine
keywords: vesicle bilayer dynamics; vesicle size dependent dynamics; vesicles chainlength dependent dynamics