The effect of lipid composition on the permeability of fluorescent markers from photosensitized membranes.

Abstract

There is evidence indicating that the cellular locus of PDT action by amphiphilic sensitizers are the cellular membranes. The photosensitization process causes oxidative damage to membrane components that can result in the cell's death. However, it was not yet established whether lipid oxidation can cause free passage of molecules through the membrane and, as a result, be the primary cause of the cell's death. In this work, we studied the effect of liposomes' lipid composition on the kinetics of the leakage of three fluorescent dyes, calcein, carboxyfluorescein and DTAF, which were trapped in the intraliposomal aqueous phase, after photosensitization with the photosensitizer deuteroporphyrin. We found that as the degree of fatty acid unsaturation increased, the photosensitized passage of these molecules through the lipid bilayer increased. We also found that the rate of leakage of these molecules was affected by their size and bulkiness as well as by their net electric charge. In liposomes that are composed of a lipid mixture similar to that of natural membranes, the observed passage of molecules through the membrane is slow. Thus, the photodynamic damage to lipids does not appear to be severe enough to be an immediate, primary cause of cell death in biological photosensitization.

• Authors: Shany Ytzhak, Hana Weitman, Benjamin Ehrenberg
• Journal: Photochemistry and photobiology (Photochem Photobiol) 2013 May-Jun Vol. 89 Issue 3 Pg. 619-24 ISSN: 1751-1097 [Electronic] United States
• PMID: 23278678 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2013 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2013 The American Society of Photobiology.

Chemical References

• Deuteroporphyrins
• Fluoresceins
• Fluorescent Dyes
• Liposomes
• Membrane Lipids
• Photosensitizing Agents
• 5-((4,6-dichloro-1,3,5-triazin-2-yl)amino)fluorescein
• 6-carboxyfluorescein
• deuteroporphyrin-IX
• fluorexon

Topics

• Cell Membrane (chemistry)
• Cell Membrane Permeability
• Deuteroporphyrins (chemistry)
• Diffusion
• Fluoresceins (chemistry)
• Fluorescent Dyes (chemistry)
• Hydrophobic and Hydrophilic Interactions
• Kinetics
• Liposomes (chemistry)
• Membrane Lipids (chemistry)
• Photosensitizing Agents (chemistry)
• Static Electricity