Interaction of Room Temperature Ionic Liquid Solutions with a Cholesterol Bilayer

Cromie, Stephen; Pópolo, Mario G. Del; Ballone, Pietro

doi:10.1021/jp904060y

Cited by 40 publications

(45 citation statements)

References 29 publications

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“…) At low concentrations of RTILs, the variation of the main phase transition of phospholipids bilayers is negligible, and at high concentration the variation is of the order of 5 to 10 degrees, sometimes reaching 20 degrees, but this just before the collapse of the bilayers. Several other MD simulation studies have also been done on this subject (e.g., Bingham and Ballone 2012;Cromie et al 2009;Lim et al 2015), which give access to the detailed mechanisms of interactions. In Lim et al, for example, the mutual interaction between RTIL cations once absorbed into the membrane has been studied, and the measured increment of permeability due to the absorption of RTILs has been related to their antibacterial activity.…”

Section: Introductionmentioning

confidence: 99%

Room-temperature ionic liquids meet bio-membranes: the state-of-the-art

Benedetto

2017

Biophys Rev

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Room-temperature ionic liquids (RTIL) are a new class of organic salts whose melting temperature falls below the conventional limit of 100°C. Their low vapor pressure, moreover, has made these ionic compounds the solvents of choice of the so-called green chemistry. For these and other peculiar characteristics, they are increasingly used in industrial applications. However, studies of their interaction with living organisms have highlighted mild to severe health hazards. Since their cytotoxicity shows a positive correlation with their lipophilicity, several chemical-physical studies of their interactions with biomembranes have been carried out in the last few years, aiming to identify the molecular mechanisms behind their toxicity. Cation chain length and anion nature of RTILs have seemed to affect lipophilicity and, in turn, their toxicity. However, the emerging picture raises new questions, points to the need to assess toxicity on a case-by-case basis, but also suggests a potential positive role of RTILs in pharmacology, bio-medicine and bio-nanotechnology. Here, we review this new subject of research, and comment on the future and the potential importance of this emerging field of study.

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Section: Introductionmentioning

confidence: 99%

Room-temperature ionic liquids meet bio-membranes: the state-of-the-art

Benedetto

2017

Biophys Rev

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“…Some studies that applied molecular dynamics (MD) simulations to analyze the impact of ILs on model membranes have already been reported: Cromie et al studied the interactions of 1-butyl-3-methylimidazolium ILs with a cholesterol bilayer and observed cation adsorption at the water−cholesterol interface. 39 Bingham and Ballone investigated the effect of 1-butyl-3-methylimidazolium based ILs on a membrane composed of POPC phospholipids and observed cations that diffused with their alkyl tail first into the bilayer. 40 Klaḧn and Zacharias studied the insertion of 1-octyl-3-methylimidazolium cations into membrane models of cancerous and healthy cells, whereby they identified a protective function of additional cholesterol in membranes of healthy cells that impeded cation insertion.…”

Section: Introductionmentioning

confidence: 99%

Impact of Ionic Liquids in Aqueous Solution on Bacterial Plasma Membranes Studied with Molecular Dynamics Simulations

et al. 2014

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The impact of five different imidazolium-based ionic liquids (ILs) diluted in water on the properties of a bacterial plasma membrane is investigated using molecular dynamics (MD) simulations. Cations considered are 1-octyl-3-methylimidazolium (OMIM), 1-octyloxymethyl-3-methylimidazolium (OXMIM), and 1-tetradecyl-3-methylimidazolium (TDMIM), as well as the anions chloride and lactate. The atomistic model of the membrane bilayer is designed to reproduce the lipid composition of the plasma membrane of Gram-negative Escherichia coli. Spontaneous insertion of cations into the membrane is observed in all ILs. Substantially more insertions of OMIM than of OXMIM occur and the presence of chloride reduces cation insertions compared to lactate. In contrast, anions do not adsorb onto the membrane surface nor diffuse into the bilayer. Once inserted, cations are oriented in parallel to membrane lipids with cation alkyl tails embedded into the hydrophobic membrane core, while the imidazolium-ring remains mostly exposed to the solvent. Such inserted cations are strongly associated with one to two phospholipids in the membrane. The overall order of lipids decreased after OMIM and OXMIM insertions, while on the contrary the order of lipids in the vicinity of TDMIM increased. The short alkyl tails of OMIM and OXMIM generate voids in the bilayer that are filled by curling lipids. This cation induced lipid disorder also reduces the average membrane thickness. This effect is not observed after TDMIM insertions due to the similar length of cation alkyl chain and the fatty acids of the lipids. This lipid-mimicking behavior of inserted TDMIM indicates a high membrane affinity of this cation that could lead to an enhanced accumulation of cations in the membrane over time. Overall, the simulations reveal how cations are inserted into the bacterial membrane and how such insertions change its properties. Moreover, the different roles of cations and anions are highlighted and the fundamental importance of cation alkyl chain length and its functionalization is demonstrated.

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“…computational means Cromie et al, 2009;Yoo et al, 2016), although the size of the sample may currently be too limited 80 for all effects to show in computations . Also physical probes, such as neutron reflectometry (Benedetto et al, 2014), fluorescent microscopy (Yoo et al, 2016), or small-angle X-ray scattering (SAXS) , have been used.…”

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confidence: 99%