Phases and phase transitions of the phosphatidylcholines

Koynova, Rumiana; Caffrey, Martin

doi:10.1016/s0304-4157(98)00006-9

Cited by 1,019 publications

(1,036 citation statements)

References 598 publications

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“…The apparent partition coefficient for PFOS between DPPC bilayers and the bulk aqueous phase (K = X DPPC /X aq , mole fraction basis) was estimated according to following equation [22] (Eq.2), where ΔT m is the change in melting temperature, R is the gas constant, T m,o is the melting temperature of hydrated DPPC, ΔH m is the phase transition enthalpy (36.4 KJ/mol [28]), C PFOS, o is the initial aqueous PFOS concentration, and C DPPC is the lipid concentration. Inoue and coworkers [22] have used Eq.2 to determine partition coefficients for a number of surfactants with hydrocarbon and fluorinated tails, including sodium perfluorooctanoate.…”

Section: Fluorescence Studiesmentioning

confidence: 99%

Mixing of perfluorooctanesulfonic acid (PFOS) potassium salt with dipalmitoyl phosphatidylcholine (DPPC)

Lehmler

Xie

Bothun

et al. 2006

Colloids and Surfaces B: Biointerfaces

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Perfluorooctane-1-sulfonic acid (PFOS) is emerging as an important persistent environmental pollutant. To gain insight into the interaction of PFOS with biological systems, the mixing behavior of dipalmitoylphosphatidylcholine (DPPC) with PFOS was studied using differential scanning calorimetry (DSC) and fluorescence anisotropy measurements. In the DSC experiments the onset temperature of the DPPC pretransition (T p ) decreased with increasing PFOS concentration, disappearing at X DPPC ≤ 0.97. The main DPPC phase transition temperature showed a depression and peak broadening with increasing mole fraction of PFOS in both the DSC and the fluorescence anisotropy studies. From the melting point depression in the fluorescence anisotropy studies, which was observed at a concentration as low as 10 mg/L, an apparent partition coefficient of K = 5.7 × 10 4 (mole fraction basis) was calculated. These results suggest that PFOS has a high tendency to partition into lipid bilayers. These direct PFOS-DPPC interactions are one possible mechanism by which PFOS may contribute to adverse effects, for example neonatal mortality, in laboratory studies and possibly in humans.

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Section: Fluorescence Studiesmentioning

confidence: 99%

Mixing of perfluorooctanesulfonic acid (PFOS) potassium salt with dipalmitoyl phosphatidylcholine (DPPC)

Lehmler

Xie

Bothun

et al. 2006

Colloids and Surfaces B: Biointerfaces

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“…Contributions from thermochromism,2 thermal fluctuations in viscosity16 and the transition from S o into L d membranes to this inversion were dissected using DOPC LUVs, which are in L d phase at both temperatures ( T m (DPPC)=41 °C, T m (DOPC)=−18 °C) 17. At 55 °C, the emission spectra of 1 in L d DPPC and DOPC membranes were superimposable (Figure 3 d, red).…”

mentioning

confidence: 96%

White‐Fluorescent Dual‐Emission Mechanosensitive Membrane Probes that Function by Bending Rather than Twisting

et al. 2018

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Bent N,N′‐diphenyl‐dihydrodibenzo[a,c]phenazine amphiphiles are introduced as mechanosensitive membrane probes that operate by an unprecedented mechanism, namely, unbending in the excited state as opposed to the previously reported untwisting in the ground and twisting in the excited state. Their dual emission from bent or “closed” and planarized or “open” excited states is shown to discriminate between micelles in water and monomers in solid‐ordered (So), liquid‐disordered (Ld) and bulk membranes. The dual‐emission spectra cover enough of the visible range to produce vesicles that emit white light with ratiometrically encoded information. Strategies to improve the bent mechanophores with expanded π systems and auxochromes are reported, and compatibility with imaging of membrane domains in giant unilamellar vesicles by two‐photon excitation fluorescence (TPEF) microscopy is demonstrated.

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“…But there still exists lack of results on the study of phase behavior of PEGylated lipids for comparison. 53 The main transition temperatures for fully hydrated phosphatidylcholines are reported in the literature to be $23 and 548C for lipid chain length of 14 and 18, respectively. 53 Hence, our next assignment should be the study of comparison of thermal properties of conventional fully hydrated phospholipids with the new hydrated QuSomes samples.…”

Section: Discussionmentioning

confidence: 99%

“…53 The main transition temperatures for fully hydrated phosphatidylcholines are reported in the literature to be $23 and 548C for lipid chain length of 14 and 18, respectively. 53 Hence, our next assignment should be the study of comparison of thermal properties of conventional fully hydrated phospholipids with the new hydrated QuSomes samples. Since QuSomes have PEG headgroup instead of ester headgroup in contrast to conventional phospholipids, we anticipate remarkable different behaviors in their stability.…”

Section: Discussionmentioning

confidence: 99%

“…This also illustrates an increasing cooperativity in phase transition temperature as lipid acyl chain lengths increase (i.e., T m values increase with increasing chain length). 53 However, the postphase transition phenomenon observed in both DSC and Raman methods for GDS-23 are not easily detectable via infrared techniques. On the other hand, the lipid GDO-12 with associated monounsaturated hydrocarbon chains did not show any order-disorder phenomena at increased temperature when investigated using all three techniques.…”

Section: Comparison Of Phase Transition Profiles Derived From Differementioning

confidence: 99%

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Vibrational spectroscopic studies of newly developed synthetic biopolymers

2010

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Vibrational spectroscopic techniques such as near‐infrared (NIR), Fourier transform infrared (FTIR), and Raman spectroscopy are valuable diagnostic tools that can be used to elucidate comprehensive structural information of numerous biological samples. In this review article, we have highlighted the advantages of nanotechnology and biophotonics in conjunction with vibrational spectroscopic techniques in order to understand the various aspects of new kind of synthetic biopolymers termed as polyethylene glycol (PEG)ylated lipids. In contrast to conventional phospholipids, these novel lipids spontaneously form liposomes or nanovesicles upon hydration, without the supply of external activation energy. The amphiphiles considered in this study differ in their hydrophobic acyl chain length and contain different units of PEG hydrophilic headgroups. We have further explored the thermotropic phase behaviors and associated changes in the conformational order/disorder of such lipids by using variable‐temperature FTIR and Raman spectroscopy. Phase transition temperature profiles and correlation between various spectral indicators have been identified by either monitoring the shifts in the vibrational peak positions or plotting vibrational peak intensity ratios in the CH stretching region as a function of temperature. To supplement our observations of phase transformations, a thermodynamic approach known as differential scanning calorimetry (DSC) has been applied and revealed a good agreement with the infrared and Raman spectroscopic data. Finally, the investigation of thermal properties of lipids is extremely crucial for numerous purposes, thus the results obtained in this work may find application in a wide variety of studies including the development of PEGylated lipid based drug and substances delivery vehicles. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 403–417, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com

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Phases and phase transitions of the phosphatidylcholines

Cited by 1,019 publications

References 598 publications

Mixing of perfluorooctanesulfonic acid (PFOS) potassium salt with dipalmitoyl phosphatidylcholine (DPPC)

Mixing of perfluorooctanesulfonic acid (PFOS) potassium salt with dipalmitoyl phosphatidylcholine (DPPC)

White‐Fluorescent Dual‐Emission Mechanosensitive Membrane Probes that Function by Bending Rather than Twisting

Vibrational spectroscopic studies of newly developed synthetic biopolymers

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