Vesicle and bilayer formation of diphytanoylphosphatidylcholine (DPhPC) and diphytanoylphosphatidylethanolamine (DPhPE) mixtures and their bilayers' electrical stability
Artikel i vetenskaplig tidskrift, 2011

Lipid bilayers are of interest in applications where a cell membrane mimicking environment is desired. The performance of the lipid bilayer is largely dependent on the physical and chemical properties of the component lipids. Lipid bilayers consisting of phytanoyl lipids have proven to be appropriate choices since they exhibit high mechanical and chemical stability. In addition, such bilayers have high electrical resistances. Two different phytanoyl lipids, 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) and 1,2-diphytanoyl-sn-glycero-3-phosphoethanolamine(DPhPE), and various combinations of the two have been investigated with respect to their behavior in aqueous solutions, their interactions with solid surfaces, and their electrical stability. Dynamic light scattering, nuclear magnetic resonance diffusion, and cryogenic transmission electron microscopy measurements showed that pure DPhPC as well as mixtures of DPhPC and DPhPE consisting of greater than 50% (mol%) DPhPC formed unilamellar vesicles. If the total lipid concentration was greater than 0.15 g/l, then the vesicles formed solid-supported bilayers on plasma-treated gold and silica surfaces by the process of spontaneous vesicle adsorption and rupture, as determined by quartz crystal microbalance with dissipation monitoring and atomic force microscopy. The solid-supported bilayers exhibited a high degree of viscoelasticity, probably an effect of relatively high amounts of imbibed water or incomplete vesicle fusion. Lipid compositions consisting of greater than 50% DPhPE formed small flower-like vesicular structures along with discrete liquid crystalline structures, as evidenced by cryogenic transmission electron microscopy. Furthermore, electrophysiology measurements were performed on bilayers using the tip-dip methodology and the bilayers' capacity to retain its electrical resistance towards an applied potential across the bilayer was evaluated as a function of lipid composition. It was shown that the lipid ratio significantly affected the bilayer's electrical stability, with pure DPhPE having the highest stability followed by 3DPhPC:7DPhPE and 7DPhPC:3DPhPE in decreasing order. The bilayer consisting of 5DPhPC:5DPhPE had the lowest stability towards the applied electrical potential.

phospholipid-bilayers

Tip-dip

channel recordings

DPhPC

gold surfaces

QCM-D

NMR

quartz-crystal microbalance

Cryo-TEM

lipid-bilayers

supported bilayers

membrane electroporation

molecular-dynamics

DPhPE

Electrophysiology

Lipid bilayer

Electroporation

Vesicle fusion

atomic-force microscopy

diffusion

integral-equations

DLS

AFM

Vesicles

Författare

Martin Andersson

Chalmers, Kemi- och bioteknik, Teknisk ytkemi

J. Jackman

University of Florida

D. Wilson

University of Florida

Patrik Jarvoll Dae

Chalmers, Kemi- och bioteknik

V. Alfredsson

Lunds universitet

G. Okeyo

University of Florida

R. Duran

University of Florida

Colloids and Surfaces B: Biointerfaces

0927-7765 (ISSN)

Vol. 82 550-561

Ämneskategorier

Kemi

DOI

10.1016/j.colsurfb.2010.10.017