Thermal Modulation of Photoisomerization in Double-Azobenzene-Chain Liposomes

Abstract

Cationic double-azobenzene-chain lipid 5 undergoes efficient trans → cis photoisomerization in MeCN solution and in 1:9 coliposomes with bisether lipid 2 at temperatures above 20 °C. However, in 1:1 5/2 coaggregates, or in pure liposomal 5, the extent of photoisomerization is very sensitive to temperature; for example, it is limited to ≤10% below 40 °C. Dispersed 1:9 coliposomes of 5 and 2 spontaneously segregate into domains rich in the individual lipids. Thermal cis → trans isomerization of 5 in MeCN solution and in 1:9 5/2 coliposomes proceeds readily between 20 and 60 °C with activation energies of 19−20 kcal/mol. The photoisomerization of 5 in pure liposomes or in 1:1 5/2 coliposomes is less efficient than that of its single-azobenzene-chain analogue, 1, under comparable conditions.

H-Aggregation of Azobenzene-Substituted Amphiphiles in Vesicular Membranes

“…Azobenzene-derived surfactants have been used for the control of membrane permeability , and other macroscopic properties and can be employed in aggregates such as bilayers/vesicles, ,, monolayers/Langmuir−Blodgett (LB) films, and micelles …”

Spectroscopic characterizations of non-amphiphilic 2-(4-biphenylyl)-6-phenyl benzoxazole molecules at the air–water interface and in Langmuir–Blodgett films

“…Lipid based supramolecular assemblies may be organized as multilamellar or tubular micro-structure [24,25] as well as in nonlamellar inverted hexagonal or cubic packings. As host structures, lipid/water phases possess a high capacity to encapsulate various water soluble species among which fluorescent and chemiluminescent dyes have been studied [26,27]. Moreover, the photophysical properties of molecules incorporated in these supramolecular assemblies show enormous changes, which reflect the interaction of the molecules with their microenvironment providing an insight into the structure-property co-relationship in these systems.…”

Spectroscopic Characterizations of Nonamphiphilic 2,5-Bis (5-Tert-Butyl-Benzoxazolyl)-Thiophene Molecules at the Air–water Interface and in Langmuir–blodgett Films

“…17,18 Lipid/water phases cause a high capacity to encapsulate various water soluble species among which fluorescent and chemiluminescent dyes have been studied. 19,20 The photophysical characteristics of molecules incorporated in these supramolecular assemblies show enormous changes, which reflect the interaction of the molecules with their microenvironment providing an insight into the structureproperty co-relationship in these systems.…”