Using Curvature Power To Map the Domain of Inverse Micellar Cubic Phases: The Case of Aliphatic Aldehydes in 1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine

Abstract

Oxylipins, or fatty aldehydes, are a class of molecules produced from membrane lipids as a result of oxidative stress or enzyme-mediated peroxidation. Here we report the effects of two biologically important fatty aldehydes, trans,trans-2,4-decanedienal (DD) and cis-11-hexadecenal (HD), on the phase behavior of the lipid 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) in water. We compare the phase behavior of DD/DOPE and HD/DOPE mixtures to the phase behavior of oleic acid/DOPE mixtures and show that DD, HD, and oleic acid have similar effects on the phase diagrams of DOPE. Notably, both DD and HD, like oleic acid, induce the formation of Fd3m inverse micellar cubic phases in DOPE/water mixtures. This is the first time that Fd3m phases in fatty aldehyde-containing mixtures have been reported. We assess the effects of DD, HD, and oleic acid on DOPE in terms of lipid spontaneous curvatures and propose a method to predict the formation of Fd3m phases from the curvature power of amphiphiles. This methodology predicts that Fd3m phases will become stable if the spontaneous curvature of a lipid mixture is -0.48 ± 0.05 nm or less.

Lipid monolayer spontaneous curvatures: A collection of published values

“…The significance of this observation is that MGDG lipids are not found in E. coli so these observations support the intrinsic curvature hypothesis, as modelled in Acholeplasma laidlawii [35]. HD DOPE -0.0520 ± 0.0400 Water [23,71] cR DOPE -0.1130 ± 0.0600 Water [23] tR DOPE -0.1050 ± 0.1600 Water [23] tRA DOPE -0.0630 ± 0.0400 Water 18:1(n=9), 18:1(n=9) DGlcDOG -0.0076 e Water 40 [35] 18:1(n=9), 18:1(n=9) GPDGlcDOG -0.0130 e Water 40 [35] 18:1(n=9), 18:1(n=9) MGlcDOG -0.0400 e Water 40 [35]…”

Overcoming Therapeutic Challenges of Antibiotic Delivery with Cubosome Lipid Nanocarriers

“…Although in some conditions they are similar, here we will refer to intrinsic curvature as the geometric derivation, i.e., c 0 , is a geometric notion describing radius of curvature formed by a lipid assembly in a hexagonal phase in the absence of any strain; c 0 = 1/ R 0 as depicted in Supporting Figure S3. Values for c 0 are determined experimentally through small-angle X-ray diffraction (SAXD) and may be considered as a means to quantify each molecules’ curvature contributions. , This value can effectively parametrize each lipid NC system and target membrane system; e.g., bilayer-forming lipids tend to exhibit positive near zero c 0 values (cylinder shape), while H II /Q II forming (cone) tend to exhibit negative c 0 values . Moreover, one could expect that any direct mixing process such as fusion may be influenced by the c 0 values of the fusing lipids.…”

Water is a preservative of microbes

“…Unfavourable entropic interactions between hydrophobic alkyl chains on lipids are the driving force for self‐aggregation of lipid molecules. However, the self‐organized structure of these lipids into the bilayer configuration critical for cell membrane integrity is dependent on the amount of water and the presence of other molecules, such as anions, cations and solvents, as well as temperature and pressure in the system (Dymond et al ., 2016; Burrell et al ., 2017). Water therefore appears to play a role in preserving the bilayer configuration and structural integrity and fluidity/energetics of the cell membrane (Dymond, 2016); and a structurally intact and functionally active membrane is critical to preservation of the cell (Crowe et al .,1984; Potts, 1994; Sano et al ., 1999; Faria et al ., 2009).…”