Effect of ionic liquids on the structures of ripple phases of model cellular membranes
05 Nov 2020-Vol. 2265, Iss: 1, pp 030024
TL;DR: In this paper, a small angle x-ray diffraction study has revealed the change in inter-bilayer spacing in the presence of imidazolium-based ionic liquids in the ripple phase of the bilayer.
Abstract: The potential biomedical applications of ionic liquids (ILs) need an understanding of the effects of the molecules in living organisms. Researchers are still exploring the molecular level description of this interaction. Any foreign molecule affecting a living organism has to interact first with the outer layer of a cell, which is mainly composed of a phospholipid bilayer. Here, to understand the membrane-IL interaction, a zwitterionic lipid has been chosen to prepare multilamellar vesicles (MLVs) which are the model cellular membranes. Small angle x-ray diffraction study has revealed the change in inter-bilayer spacing in the presence of imidazolium based ILs in the ripple phase of the bilayer. The investigation was extended further to understand the role of a negatively charged lipid in the MLVs. This study indicates that the cations of an IL screen electrostatic repulsion between the negatively charged lipids and induce the formation of a vesicle.
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01 Jan 1986
TL;DR: Molecular cell biology, Molecular cell biology , مرکز فناوری اطلاعات و اصاع رسانی, کδاوρزی
Abstract: Molecular cell biology , Molecular cell biology , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
6,754 citations
TL;DR: This review will summarize the major historical discoveries and theories that tackled the existence and structure of membranes and will analyze how these theories impacted the understanding of the cell.
Abstract: All modern cells are bounded by cell membranes best described by the fluid mosaic model. This statement is so widely accepted by biologists that little attention is generally given to the theoretical importance of cell membranes in describing the cell. This has not always been the case. When the Cell Theory was first formulated in the XIXth century, almost nothing was known about the cell membranes. It was not until well into the XXth century that the existence of the plasma membrane was broadly accepted and, even then, the fluid mosaic model did not prevail until the 1970s. How were the cell boundaries considered between the articulation of the Cell Theory around 1839 and the formulation of the fluid mosaic model that has described the cell membranes since 1972? In this review I will summarize the major historical discoveries and theories that tackled the existence and structure of membranes and I will analyze how these theories impacted the understanding of the cell. Apart from its purely historical relevance, this account can provide a starting point for considering the theoretical significance of membranes to the definition of the cell and could have implications for research on early life. This article was reviewed by Dr. Etienne Joly, Dr. Eugene V. Koonin and Dr. Armen Mulkidjanian.
126 citations
TL;DR: The insertion of ILs to cause the swelling of the lipid bilayer shows strong dependence on the hydrophobicity of IL cationic alky chain and anions and is strongly correlated with the reported IL cytotoxicity.
Abstract: Ionic liquids (ILs) have been widely considered and used as “green solvents” for more than two decades. However, their ecotoxicity results have contradicted this view, as ILs, particularly hydrophobic ones, are reported to exhibit high toxicity. Yet the origin of their toxicology remains unclear. In this work, we have investigated the interaction of amphiphilic ILs with a lipid bilayer as a model cell membrane to understand their cytotoxicity at a molecular level. By employing fluorescence imaging and light and X-ray scattering techniques, we have found that amphiphilic ILs could disrupt the lipid bilayer by IL insertion, end-capping the hydrophobic edge of the lipid bilayer, and eventually disintegrating the lipid bilayer at high IL concentration. The insertion of ILs to cause the swelling of the lipid bilayer shows strong dependence on the hydrophobicity of IL cationic alky chain and anions and is strongly correlated with the reported IL cytotoxicity.
92 citations
TL;DR: It appears that the truly metastable ripple phase is expressed by the second ripple structure although in the course of the actual cooling transition both the secondary and primary ripple structures form and coexist.
61 citations
TL;DR: The analysis of long wavelength fluctuations of the bilayers shows that RTIL sorption causes a general decrease of the lipid/water interfacial tension and bending rigidity, pointing to the destabilizing effect of RTILs on lipid bilayers.
Abstract: Molecular dynamics simulations in the NPT ensemble have been carried out to investigate the effect of two room temperature ionic liquids (RTILs), on stacks of phospholipid bilayers in water. We consider RTIL compounds consisting of chloride ([bmim][Cl]) and hexafluorophosphate ([bmim][PF6]) salts of the 1-buthyl-3-methylimidazolium ([bmim](+)) cation, while the phospholipid bilayer is made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Our investigations focus on structural and dynamical properties of phospholipid and water molecules that could be probed by inelastic and quasi-elastic neutron scattering measurements. The results confirm the fast incorporation of [bmim](+) into the lipid phase already observed in previous simulations, driven by the Coulomb attraction of the cation for the most electronegative oxygens in the POPC head group and by sizeable dispersion forces binding the neutral hydrocarbon tails of [bmim](+) and of POPC. The [bmim](+) absorption into the bilayer favours the penetration of water into POPC, causes a slight but systematic thinning of the bilayer, and further stabilises hydrogen bonds at the lipid/water interface that already in pure samples (no RTIL) display a lifetime much longer than in bulk water. On the other hand, the effect of RTILs on the diffusion constant of POPC (DPOPC) does not reveal a clearly identifiable trend, since DPOPC increases upon addition of [bmim][Cl] and decreases in the [bmim][PF6] case. Moreover, because of screening, the electrostatic signature of each bilayer is only moderately affected by the addition of RTIL ions in solution. The analysis of long wavelength fluctuations of the bilayers shows that RTIL sorption causes a general decrease of the lipid/water interfacial tension and bending rigidity, pointing to the destabilizing effect of RTILs on lipid bilayers.
56 citations