Spatial correlation of lipid phase fluctuations in model membranes studied with two-photon fluorescence microscopy

The temporal dynamics of lipid phase fluctuations and the spatial organization of model lipid membranes was studied using Two-photon excitation fluorescence microscopy. Lipid membranes of different composition were reconstituted in Giant Unilamellar Vesicles (GUVs) and labeled with the environment sensitive dye LAURDAN whose spectral properties are sensitive to the lipid phase. The Generalized Polarization (GP) function was used to quantify the lipid phase state as detected by LAURDAN. Long lived micron sized structures were detected on membranes composed of a single lipid specie as the temperature was decreases towards the main (Liquid-crystalline to gel) phase transition by calculating the GP autocorrelation function of circular scanning measurements. In binary mixtures membranes, the influence of coexisting lipid species on the phase behavior of each other was detected and characterized comparing the experimental results with a simple two state approximation. High hydrostatic pressure was used to induce morphological transformation of the GUVs and study the coupling between mechanical stress and phase behavior of the membrane. The ability to visualize the morphological and phase behavior of single GUVs under the microscope has allowed studying the coupling between lipid phase and membrane curvature

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2012

Author dc:creator

• Celli, Anna

Contributors dc:contributor

• Gratton, E.

• Chemistry, Biochemistry
• Biophysics, General
• lipid density fluctuations
• fluorescence microscopy
• Spatial correlation
• membranes
• Biomembranes
• Giant Unilamellar Vesicles

Statement dc:rights

• © 2006 Anna Celli

Language dc:language

en

Identifier

5385320

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/32104