Elucidating the Effects of Cholesterol on the Molecular Packing of Double-chained Cationic Lipid Langmuir Monolayers by Infrared Reflection-absorption Spectroscopy

Kuo, An Tsung; Chang, Chien Hsiang

doi:10.5650/jos.ess14266

Cited by 4 publications

(4 citation statements)

References 57 publications

(36 reference statements)

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“…As is evident from the results of this study, in the form of air/liquid deposited monolayers, the amphiphiles behave quite differently, as DPPG is able to form a condensed layer upon compression, whereas DHDAB exhibits expanded layer characteristics, even at high surface pressure. Furthermore, DHDAB monolayers must be considered as being metastable, due to the solubility of the surfactant leading to a small loss of material into the subphase during compression (Kuo and Chang, 2015). Although both DPPG and DHDAB were in the gel phase at ambient temperature (Adati and Feitosa, 2015;Schmid et al, 2018) the differences in their monolayer compressibility behavior indicates that a mixing gap may be expected somewhere in the binary phase diagram (Sackmann and Demus, 1973), which needed to be taken into account when assessing their miscibility.…”

Section: Discussionmentioning

confidence: 99%

Enhanced chain packing achieved via putative headgroup ion-triplet formation in binary anionic lipid/cationic surfactant mixed monolayers

Wölk

Hause

Gutowski

et al. 2019

Chemistry and Physics of Lipids

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Lipid/surfactant miscibility was investigated in monolayers composed of binary mixtures of dipalmitoylphosphatidylglycerol (DPPG) and dihexadecyl dimethylammonium bromide (DHDAB). Langmuir monolayers formed from biomimetic DPPG/DHDAB mixtures based on the anionic:cationic lipid ratios observed in the bacterium Staphylococcus aureus (7:3 and 1:1) were examined alongside those of the pure amphiphiles and a surfactant rich 3:7 mixture. Using a combination of GIXD, TRXF and IRRAS, DPPG/DHDAB 1:1 monolayers were found to form a more stabilised condensed phase compared to pure DPPG, which was composed entirely of electrostatically neutral ion pairs, analogous to the so-called catanionic amphiphiles spontaneously formed by single-chain surfactants with opposing headgroup charges. Despite the lack of lateral charge repulsion the ion paired phase of DPPG/DHDAB exhibited slightly looser chain packing that was observed for DPPG indicating a significant steric effect on packing geometry caused by ion pair formation. Surprisingly, the 7:3 mixture of DPPG/DHDAB formed an completely condensed phase, with no isotherm transitions, in which the chain packing was significantly closer than was found for either DPPG or the totally ion paired monolayer. It is postulated that this mixture forms a distinct DPPG/DHDAB/DPPG ion triplet phase in which the overall negative charge is delocalised across the headgroups. Vesicles composed from the 7:3 mixture formed highly stable dispersions with an increased gel to liquid crystalline phase transition temperature with respect to its pure components. Increasing the proportion of DHDAB above 50 mol% led to demixing between the condensed ion paired phase and the more fluid surfactant, as was clearly observed in epifluorescence images taken of the surface films.

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Section: Discussionmentioning

confidence: 99%

Enhanced chain packing achieved via putative headgroup ion-triplet formation in binary anionic lipid/cationic surfactant mixed monolayers

Wölk

Hause

Gutowski

et al. 2019

Chemistry and Physics of Lipids

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“…The disordering effect of cholesterol on bilayers of the catanionic vesicles has been ascribed to the fact that the added cholesterol in the rigid bilayers would increase the space between the molecular headgroups and create a void near the bilayer centers, decreasing the conformational order in the front and end segments of the hydrocarbon chains 25 . Although the sterol ring of cholesterol hindered the neighboring hydrocarbon chains in motion, cholesterolinduced conformational disorder in the front and end segments of the hydrocarbon chains overwhelmed the ordering effect of the sterol ring of cholesterol, resulting in an apparent conformational disorder of the molecular hydrocarbon chains 25,41 .…”

Section: Molecular Packingmentioning

confidence: 99%

Enhanced Physical Stability of Mixed Ion Pair Amphiphile/Double-chained Cationic Surfactant Vesicles in the Presence of Cholesterol

Kuo

Yang

et al. 2018

J. Oleo Sci.

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In this study, a pseudodouble-chained ion pair amphiphile (IPA), hexadecyltrimethylammoniumdodecylsulfate (HTMA-DS), and dialkyldimethylammonium bromide (DXDAB) with different chain lengths were used as the main materials to fabricate positively charged catanionic vesicles with various mole fractions of cholesterol. The effects of cholesterol and DXDAB alkyl chain length on physical stability of the catanionic vesicles were then investigated by size, zeta potential, and Fourier transform infrared analyses. With the presence of cholesterol in the mixed HTMA-DS/DXDAB vesicles or with increasing the DXDAB content in the presence of a proper amount of cholesterol, the physical stability of the catanionic vesicles could be enhanced. The spacing effect of cholesterol would reduce the counterion binding tendency at the charged vesicle surfaces, resulting in a more pronounced charge character of the catanionic vesicles. Furthermore, cholesterol-induced disordered structure contributed to the flexibility of the vesicular bilayers. Thus the physical stability of the vesicles was improved by adding cholesterol. With increasing the hydrocarbon chain length of DXDAB, cholesterol located toward the middle of the bilayers, enhancing the effects of cholesterol on charge and molecular packing characteristics of the vesicles. This led to a more pronounced stability enhancement effect on the vesicles with a longer alkyl chain length of DXDAB. The results suggested that the presence of cholesterol in the HTMA-DS/DXDAB catanionic vesicles could enhance vesicle stability through adjusting intra-vesicle and/or inter-vesicle interactions. In addition, the stability enhancement effect was more pronounced in the systems with a long DXDAB alkyl chain. The findings will be useful for developing new formulas of catanionic vesicles as drug delivery carriers.

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“…Cholesterol has been suggested to play a role in stable vesicle formation by adjusting the molecular packing of the vesicular bilayer. The Langmuir monolayer approach with infrared reflection-absorption spectroscopy (IRRAS) elucidated the effects of cholesterol on molecular packing of double-chained cationic surfactants [80]. Combining cholesterol with DXDAB monolayers at the air-water interface (X meaning the hydrocarbon chain length) reduced desorption of DXDAB with short alkyl chains, for example, ditetradecyldimethylammonium bromide or dihexadecyldimethylammonium bromide, into the water sub-phase and condensed the DXDAB monolayers [80].…”

Section: Dodab Hybrid Assembliesmentioning

confidence: 99%

“…The Langmuir monolayer approach with infrared reflection-absorption spectroscopy (IRRAS) elucidated the effects of cholesterol on molecular packing of double-chained cationic surfactants [80]. Combining cholesterol with DXDAB monolayers at the air-water interface (X meaning the hydrocarbon chain length) reduced desorption of DXDAB with short alkyl chains, for example, ditetradecyldimethylammonium bromide or dihexadecyldimethylammonium bromide, into the water sub-phase and condensed the DXDAB monolayers [80]. For the DODAB monolayers, cholesterol had a dual effect inducing both order and disorder of the neighboring hydrocarbon chains; the flexible alkyl side-chain of cholesterol along with the corresponding portion of neighboring hydrocarbon chains formed a fluidic region, counteracting the conformational order induced by the sterol ring of cholesterol interacting with the alkyl chains [80].…”

Section: Dodab Hybrid Assembliesmentioning

confidence: 99%

The Versatile Dioctadecyldimethylammonium Bromide

Carmona-Ribeiro¹

2017

Application and Characterization of Surfactants

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Dioctadecyldimethylammonium bromide (DODAB) is a quaternary ammonium surfactant (Quat) with interesting properties and applications. In this chapter, DODAB characteristics as compared to other Quats emphasize its self-assembly in aqueous solutions and the novel applications involving this useful cationic lipid so easily combined with biomolecules and interfaces to yield a wide range of novel uses in many fields such as delivery of drugs, vaccines and genes, design of nanoparticles, modification of interfaces, and many others yet to come.

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Elucidating the Effects of Cholesterol on the Molecular Packing of Double-chained Cationic Lipid Langmuir Monolayers by Infrared Reflection-absorption Spectroscopy

Cited by 4 publications

References 57 publications

Enhanced chain packing achieved via putative headgroup ion-triplet formation in binary anionic lipid/cationic surfactant mixed monolayers

Enhanced chain packing achieved via putative headgroup ion-triplet formation in binary anionic lipid/cationic surfactant mixed monolayers

Enhanced Physical Stability of Mixed Ion Pair Amphiphile/Double-chained Cationic Surfactant Vesicles in the Presence of Cholesterol

The Versatile Dioctadecyldimethylammonium Bromide

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