The interdigitated gel phase in mixtures of cationic and zwitterionic phospholipids

Smith, Eric A.; Dea, Phoebe

doi:10.1016/j.bpc.2014.10.003

Cited by 7 publications

(7 citation statements)

References 51 publications

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“…Generally, as temperature increases the mobility and flexibility of lipids enhance, as well as the fluidity of bilayer membrane . Also, for each phospholipid type the fluorescence polarization is high in the gel phase and decreases considerably above T m . DPPC polarization curves exhibited characteristic “S shape” as a result of an intense decline in polarization values in the temperature region between 40 and 45 °C, when the main phase transition occurs (conversion of a rippled gel phase to a liquid crystal phase) as also confirmed by DSC analysis (shown in section 3.2).…”

Section: Resultssupporting

confidence: 89%

“…The increase in vesicle size from DPPC to POPC and Lipoid could be attributed to two factors: packing parameter and phase T m . Saturated phospholipids with shorter carbohydrate chains, such as DPPC (C16:0), have lower phase T m , which resulted in a smaller vesicle size, whereas phospholipids with monounsaturated carbohydrate chains, such as POPC (C16:0–18:1), have the highest packing parameter and creates bigger liposomes . Apart from that, single phospholipid provides smaller vesicle size and enhances uniformity, in comparison to the mixture of phospholipids (such as Lipoid—commercial phospholipid mixture), because a single kind of phospholipid eliminates the imperfect packing caused by the different carbohydrate chain lengths, degrees of saturation, and head groups present in the mixture .…”

Section: Resultsmentioning

confidence: 99%

“…The properties of liposomes and their future applications are closely related to physicochemical characteristics of phospholipids and sterols used in liposomes preparation. The naturally occurring glycerophospholipid DPPC, commonly used as a model membrane, has dipolar (zwitterionic) head group and presents electrically neutral lipid . DPPC, with two saturated C16 chains (Figure ), causes the formation of homogenous liposomal membrane that has regular arrangement of chains, and thus rigid structure.…”

Section: Introductionmentioning

confidence: 99%

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Comparative Effects of Cholesterol and β‐Sitosterol on the Liposome Membrane Characteristics

Jovanović

Balanč

Ota

et al. 2018

Euro J Lipid Sci & Tech

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The influence of different phospholipid types (pure phospholipids 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine, POPC, 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine, DPPC, and one commercial phospholipid mixture, Lipoid H100), sterol types (cholesterol vs. β‐sitosterol), and various sterol concentrations (5–50 mol%) on liposomal membrane fluidity, thermotropic properties, liposome size, zeta potential, and lipid oxidation kinetics using fluorescent lipid probe BODIPY 581/591 C11 (4,4‐difluoro‐5‐[4‐phenyl‐1,3‐butadienyl]‐4‐bora‐3a,4a‐diaza‐s‐indacene‐3‐undecanoic acid) are investigated. DPPC bilayer is more rigid than POPC and phospholipids mixture membranes. Pure DPPC gives the smallest liposomes, while liposomes of Lipoid H100 have the largest diameter. Both sterols reduce membrane fluidity of all liposomes, increase absolute zeta potential, cause significant changes in particle size, and decrease phase transition temperature (Tm) and enthalpy of DPPC. POPC/β‐sitosterol liposomes exhibit the most significant lipid oxidation of the lipophilic probe. Along with beneficial effects of phytosterols on human health, better membrane fluidity, more favorable and stabilizing interactions with phospholipids, smaller vesicle size, and enhanced physical stability in comparison to cholesterol are some of the encouraging results for the use of β‐sitosterol in liposome formulations for potential application in foods, pharmaceutics, and cosmetics. Practical Applications: Adjusting the composition of liposomal membrane (lipid type, sterol type, and concentration) can be used as a tool to control membrane fluidity, permeability, and thermotropic properties, and thus predict release properties, physical, thermal, and oxidative stability. A commercial phospholipid mixture of different natural phospholipids with impurities creates less uniform liposomal membrane that is characterized by higher fluidity in comparison to DPPC. The type of phospholipid has huge influence on MLVs size. β‐sitosterol, which is a phytosterol with beneficial effects on human health can be used as a replacement for cholesterol in liposomal formulations, but with the following in mind: β‐sitosterol reduces fluidity of the phospholipid bilayer to a lesser extent than cholesterol, β‐sitosterol gives smaller MLVs than cholesterol, DPPC/β‐sitosterol SUVs are bigger than 100 nm in diameter (relevant for intravenous administration), MLVs with ≥30 mol% of β‐sitosterol can be considered as physically stable (unlike those with cholesterol), irrespective to the phospholipid type. The influence of different phospholipid types, sterol types, and various sterol concentrations on liposomal membrane fluidity, thermo tropic properties, liposomesize, zeta potential, and lipid oxidation kinetics are investigated.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparative Effects of Cholesterol and β‐Sitosterol on the Liposome Membrane Characteristics

Jovanović

Balanč

Ota

et al. 2018

Euro J Lipid Sci & Tech

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“…Such organization is also evident in literature. 47 The data corresponding to d 100 spacing (rst order reection), interlayer spacing, p-p stacking and edge length of cubic lattice (a) have been presented in Table 3. In case of XRD pattern of Set-I gelators in acetonitrile, the d-spacing increases with the increase in chain length, however, gelators with very long hydrophobic chain, was found to have a considerable low value in d-spacing, suggesting a self-assembly having interdigitation with higher tilt angle.…”

Section: Wide Angle X-ray Diffractionmentioning

confidence: 99%

A systematic understanding of gelation self-assembly: solvophobically assisted supramolecular gelation via conformational reorientation across amide functionality on a hydrophobically modulated dipeptide based ambidextrous gelator, N-n-acyl-(l)Val-X(OBn), (X = 1,ω-amino acid)

Haldar

Karmakar

2015

RSC Adv.

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A systematic investigation on gelation self-assembly has been performed on a hydrophobically modulated dipeptide based ambidextrous gelator, N-n-acyl-(L)Val-X(OBn), (X = 1,ω-amino acid). To elucidate the effect of hydrophobic tuning on gelator architecture towards its gelation self-assembly, three sets of gelators with a common formula: C m H 2m+1 C(=O)NH(L)Val(C=O)NH-(CH 2 ) n -(C=O)OBn, were synthesized , Set-I includes gelators with n = 2, m = 9,11,13,15,17, for Set-II it is n = 2,3,5, m=13 and Set-III comprises of two isomeric gelators (n=2, m=15; n=10, m=7). Gelation has been critically analyzed in various apolar (aromatic and aliphatic) and polar (protic and aprotic) solvents using FESEM, CD, IR, WAXRD and rheological studies. Obtained results reveal that π-π type interaction dictates the primary molecular alignment and positioning of amide functionality across the aliphatic chain which influences the peptidic orientation in parallel (when m > n) or antiparallel (when m < n) β-sheet type organization in their self-assembly. The thermal stability, gelation number (GN), T gel and yield stress of gel systems increases with m, but for a given m, the trend goes apparently inverse with increasing n. Circular dichroism (CD) studies suggest an intriguing evidence of non-planarity of amide plane during selfassembly, highlighting the involvement of conformational change taking place during molecular organization towards its gelation. Despite complex nature of solvent-gelator interaction, the effect of Hbonding component of solubility parameters was found to have a significant role on self-assembly.Overall, supramolecular forces acting at specific functionalities encrypted in gelator backbone must overcome the solvation energy with synergic assistance of solvophobic effect towards stabilization of gel-network with optimum gelator backbone conformation for achieving required enthalpic contribution for self-assembly.

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“…In the beginning, the fluorine substitution in fatty acid chains of phospholipids was used only to probe the aggregation phenomena in membrane lipids [2]. But it was only after the revelation of interdigitation in the gel phase of F-DPPC by Hirsch [3] and coworkers that fueled the research on thermotropic phase behavior of this DPPC analog [4,5,6,7,8,9,10,11,12]. For lipid monolayers, however, only the effect of subphase temperature has been reported in pure F-DPPC and in mixed monolayers with DPPC [13].…”

Section: Introductionmentioning

confidence: 99%

Effect of Perfluoroalkyl Endgroups on the Interactions of Tri-Block Copolymers with Monofluorinated F-DPPC Monolayers

Shah

Schwieger

et al. 2017

Polymers

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Abstract:We studied the interaction of amphiphilic and triphilic polymers with monolayers prepared from F-DPPC (1-palmitoyl-2-(16-fluoropalmitoyl)-sn-glycero-3-phosphocholine), a phospholipid with a single fluorine atom at the terminus of the sn-2 chain, an analogue of dipalmitoyl-phosphatidylcholine (DPPC). The amphiphilic block copolymers contained a hydrophobic poly(propylene oxide) block flanked by hydrophilic poly(glycerol monomethacrylate) blocks (GP). F-GP was derived from GP by capping both termini with perfluoro-n-nonyl segments. We first studied the adsorption of GP and F-GP to lipid monolayers of F-DPPC. F-GP was inserted into the monolayer up to a surface pressure Π of 42.4 mN m −1 , much higher than GP (32.5 mN m −1 ). We then studied isotherms of lipid-polymer mixtures co-spread at the air-water interface. With increasing polymer content in the mixture a continuous shift of the onset of the liquid-expanded (LE) to liquid-condensed (LC) transition towards higher molecular and higher area per lipid molecule was observed. F-GP had a larger effect than GP indicating that it needed more space. At a Π-value of 32 mN m −1 , GP was excluded from the mixed monolayer, whereas F-GP stayed in F-DPPC monolayers up to 42 mN m −1 . F-GP is thus more stably anchored in the monolayer up to higher surface pressures. Images of mixed monolayers were acquired using different fluorescent probes and showed the presence of perfluorinated segments of F-GP at LE-LC domain boundaries.

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The interdigitated gel phase in mixtures of cationic and zwitterionic phospholipids

Cited by 7 publications

References 51 publications

Comparative Effects of Cholesterol and β‐Sitosterol on the Liposome Membrane Characteristics

Comparative Effects of Cholesterol and β‐Sitosterol on the Liposome Membrane Characteristics

A systematic understanding of gelation self-assembly: solvophobically assisted supramolecular gelation via conformational reorientation across amide functionality on a hydrophobically modulated dipeptide based ambidextrous gelator, N-n-acyl-(l)Val-X(OBn), (X = 1,ω-amino acid)

Effect of Perfluoroalkyl Endgroups on the Interactions of Tri-Block Copolymers with Monofluorinated F-DPPC Monolayers

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