Properties of Artificial Phospholipid Membranes Containing Lauryl Gallate or Cholesterol

Abstract

Lauryl gallate (LG) is an antioxidant agent. However, it exhibits poor solubility in water. Its interactions with the membrane result in structure evolution thus affecting the membrane functionality. In this paper the Brewster angle microscope coupled with the Langmuir trough was applied to determine the morphology, phase behaviour, thickness and miscibility of ternary Langmuir monolayers with equal mole fractions of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC); 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and an increasing mole fraction of LG. The results were discussed as regards analogous systems where cholesterol (Chol) was the third component. Moreover, the phosphatidylcholine–lauryl gallate (PC–LG) interactions were monitored by the attenuated total reflectance Fourier transform infrared spectroscopy and time-of-flight secondary ion mass spectrometry. Besides lipid composition, the addition of LG was found to be a significant factor to modulate the model membrane properties. The LG molecules adjust themselves to the PC monolayer structure. The hydrophobic fragment is dipped into the membrane interior while the hydroxyl groups of phenolic gallate moiety associate with the polar groups of PC mainly through hydrogen bonding inducing the compacting effect. LG is found to be deeply submerged within DOPC, closer to the double bonds, and its insertion practically does not affect the DPPC/DOPC membrane fluidity. This is crucial for getting more profound insight into the role of LG in stabilizing the non-raft domains, mostly exposed to oxidation in which LG can co-localize and serve its antioxidant function.

Potential Role of Plasmalogens in the Modulation of Biomembrane Morphology

“…The physical and chemical characteristics of the biomimetic materials determine the structure and morphology of the artificial membranes ( Jurak et al, 2018 ). Similarly, the physicochemical properties of the biological membranes are determined by the membrane’s proteins and phospholipids composition.…”

Partitioning of a Hybrid Lipid in Domains of Saturated and Unsaturated Lipids in a Model Cellular Membrane

“… 27 The effect of compression rate, pressure, and time on the shape of domains formed in monolayer at the air–water interface has been studied using a Brewster angle microscope. 28 , 29 A detailed review in the field can be found in ref ( 30 ). All these studies hypothesize that a model membrane with a saturated lipid, cholesterol, and hybrid lipid could be a better system to mimic a biological membrane, as they form nanodomains.…”

<p>Development, Characterization and Use of Liposomes as Amphipathic Transporters of Bioactive Compounds for Melanoma Treatment and Reduction of Skin Inflammation: A Review</p>

“…The structure of the molecular arrangement of a solution of amphiphilic compounds can be determined by the geometry of the molecules. It can be estimated by the Critical Packing Parameter (CPP) using the following equation: [32][33][34][35][36] CPP…”

“…If CPP value is <½, formation of spherical micelles will take place, in contrast when >1, formation of inverted micelles will occur. [32][33][34][35][36] Since liposomes are vesicles composed by a lipidic bilayer, CPP of the amphiphilic molecules used for their elaboration should lie between ½ and 1. Phospholipids with two hydrocarbon chains, such as phosphatidic acid, phosphatidylcholine, phosphatidylethanolamine, and phosphatidylglycerol would generate CPP in this range.…”

“…32 The CPP of dipalmitoylphosphatidylcholine, dioleoylphosphatidylcholine, and cholesterol is ~½, >½ and >1, respectively. 33 Egg yolk contains phosphatidylcholine, and soybean contains lecithin, phosphatidylethanolamine, phosphatidylinositol, and phosphatidic acid. 35,37. The CPP of these phospholipids lies between ½ and 1.…”