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Photochromism of 1,2-bis(2-methyl-5-phenylthien-3-yl)perfluorocyclopentene in liposomes

Paper ID Volume ID Publish Year Pages File Format Full-Text
27880 44048 2007 12 PDF Available
Title
Photochromism of 1,2-bis(2-methyl-5-phenylthien-3-yl)perfluorocyclopentene in liposomes
Abstract

A photochromic dithienylethene, 1,2-bis(2-methyl-5-phenylthien-3-yl)perfluorocyclopentene (1), was synthesized and incorporated into the lipid bilayer of liposomes as a strategy for demonstrating the potential for complete photocontrol over the permeability of a lipid membrane. Absorption spectroscopy and differential scanning calorimetry (DSC) were used to characterize the photochromism and inclusion of 1 in dipalmitoylphosphatidylcholine (DPPC) large unilamellar liposomes (LUVs), respectively. Absorption studies confirm that the photoisomerization of 1 in DPPC LUVs is completely reversible, although hindered due to the more restrictive and rigid environment posed by the lipid bilayer. DSC studies strongly suggest that 1 is partially buried in the hydrocarbon core of the bilayer, interacting primarily with the C2–C8 methylene region of the acyl chains of DPPC. Photoinduced changes in the membrane permeability of DPPC LUVs were assessed by monitoring changes in the fluorescence of an encapsulated fluorophore, 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS), upon photocycling 1 between the two photoisomers using ultraviolet and visible light. The fluorescence studies show that release of encapsulated HPTS is not observed following the irradiations. Thus, the photoisomerization of 1 does not lead to a large disruption in the local lipid order within the bilayer.

Keywords
Dithienylethene; Liposome; Photochromism; Photoisomerization; Quantum efficiency
First Page Preview
Photochromism of 1,2-bis(2-methyl-5-phenylthien-3-yl)perfluorocyclopentene in liposomes
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 192, Issues 2–3, 15 December 2007, Pages 130–141
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering