Lateral Diffusion in Lipid Membranes through Collective Flows

Falck, Emma; Róg, Tomasz; Karttunen, Mikko; Vattulainen, Ilpo

doi:10.1021/ja7103558

Cited by 144 publications

(183 citation statements)

References 15 publications

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“…88 Studying lipid diffusion via atomic scale molecular simulations thus requires maximal measurement times, especially since diffusion may involve complex collective motions. 21,89 Here, three qualitative trends emerged, as displayed in Figure 3: (1) under all conditions, both lipid types behaved rather similarly, the difference between them falling within error bars; (2) increase in TAP hastened diffusion slightly in the mixed bilayers (for pure DMPC, D ) (1.29 ( 0.15) × 10 -7 cm 2 /s); (3) NaCl did not have any noticeable effect on lipid diffusion, except for the slight slowdown it caused in TAP ) 6% systems.…”

Section: Resultsmentioning

confidence: 99%

Ion Dynamics in Cationic Lipid Bilayer Systems in Saline Solutions

et al. 2009

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Positively charged lipid bilayer systems are a promising class of nonviral vectors for safe and efficient gene and drug delivery. Detailed understanding of these systems is therefore not only of fundamental but also of practical biomedical interest. Here, we study bilayers comprising a binary mixture of cationic dimyristoyltrimethylammoniumpropane (DMTAP) and zwitterionic (neutral) dimyristoylphosphatidylcholine (DMPC) lipids. Using atomistic molecular dynamics simulations, we address the effects of bilayer composition (cationic to zwitterionic lipid fraction) and of NaCl electrolyte concentration on the dynamical properties of these cationic lipid bilayer systems. We find that, despite the fact that DMPCs form complexes via Na + ions that bind to the lipid carbonyl oxygens, NaCl concentration has a rather minute effect on lipid diffusion. We also find the dynamics of Cl -and Na + ions at the water-membrane interface to differ qualitatively. Cl -ions have well-defined characteristic residence times of nanosecond scale. In contrast, the binding of Na + ions to the carbonyl region appears to lack a characteristic time scale, as the residence time distributions displayed power-law features. As to lateral dynamics, the diffusion of Na + ions within the water-membrane interface consists of two qualitatively different modes of motion: very slow diffusion when ions are bound to DMPC, punctuated by fast rapid jumps when detached from the lipids. Overall, the prolonged dynamics of the Na + ions are concluded to be interesting for the physics of the whole membrane, especially considering its interaction dynamics with charged macromolecular surfaces.

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Section: Resultsmentioning

confidence: 99%

Ion Dynamics in Cationic Lipid Bilayer Systems in Saline Solutions

et al. 2009

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“…These and other related studies with model bilayer systems (i.e., liposomes; Figure 1A) suggest that cell-surface contact and nanoparticle-cell membrane interactions offer a direct pathway for cargo transport from the nanoparticle ( Figure 4E). By way of explanation, the amphiphile stabilizing layer allows the formation of a hemifusion pathway between the lipid monolayer of the nanoparticle and the bilayer of the cell that leads to the delivery of peptide cargo driven by a combination of surface tension, chemical potential, and Marangoni effects (40). This pathway is quite distinct from conventional mechanisms for liposome or nanoparticle delivery across membranes, which alternatively must proceed through vehicle endocytosis and/or disruption of the cell-surface membrane and subsequent endosomal processing to release cargo from endosomal compartments.…”

Section: Development and Characterization Of Molecularly Guided Nanopmentioning

confidence: 99%

Molecularly targeted nanocarriers deliver the cytolytic peptide melittin specifically to tumor cells in mice, reducing tumor growth

Soman¹,

Baldwin²,

Hu³

et al. 2009

J. Clin. Invest.

262

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The in vivo application of cytolytic peptides for cancer therapeutics is hampered by toxicity, nonspecificity, and degradation. We previously developed a specific strategy to synthesize a nanoscale delivery vehicle for cytolytic peptides by incorporating the nonspecific amphipathic cytolytic peptide melittin into the outer lipid monolayer of a perfluorocarbon nanoparticle. Here, we have demonstrated that the favorable pharmacokinetics of this nanocarrier allows accumulation of melittin in murine tumors in vivo and a dramatic reduction in tumor growth without any apparent signs of toxicity. Furthermore, direct assays demonstrated that molecularly targeted nanocarriers selectively delivered melittin to multiple tumor targets, including endothelial and cancer cells, through a hemifusion mechanism. In cells, this hemifusion and transfer process did not disrupt the surface membrane but did trigger apoptosis and in animals caused regression of precancerous dysplastic lesions. Collectively, these data suggest that the ability to restrain the wide-spectrum lytic potential of a potent cytolytic peptide in a nanovehicle, combined with the flexibility of passive or active molecular targeting, represents an innovative molecular design for chemotherapy with broad-spectrum cytolytic peptides for the treatment of cancer at multiple stages.

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“…This argument has been put forward long time ago to explain the long-time tails in the VACFs of simple liquids. 19 In this context, we refer to recent work by Falk et al 23 who observed collective flow patterns in the lateral motions of molecules in a lipid bilayer.…”

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confidence: 99%

Communication: Consistent picture of lateral subdiffusion in lipid bilayers: Molecular dynamics simulation and exact results

Kneller

Baczyński

Pasenkiewicz-Gierula

2011

The Journal of Chemical Physics

126

135

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This communication presents a molecular dynamics simulation study of a bilayer consisting of 128 dioleoyl-sn-glycero-3-phosphocholine molecules, which focusses on the center-of-mass diffusion of the lipid molecules parallel to the membrane plane. The analysis of the simulation results is performed within the framework of the generalized Langevin equation and leads to a consistent picture of subdiffusion. The mean square displacement of the lipid molecules evolves as ∝ tα, with α between 0.5 and 0.6, and the fractional diffusion coefficient is close to the experimental value for a similar system obtained by fluorescence correlation spectroscopy. We show that the long-time tails of the lateral velocity autocorrelation function and the associated memory function agree well with exact results which have been recently derived by asymptotic analysis [G. Kneller, J. Chem. Phys. 134, 224106 (2011)10.1063/1.3598483]. In this context, we define characteristic time scales for these two quantities.

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Lateral Diffusion in Lipid Membranes through Collective Flows

Cited by 144 publications

References 15 publications

Ion Dynamics in Cationic Lipid Bilayer Systems in Saline Solutions

Ion Dynamics in Cationic Lipid Bilayer Systems in Saline Solutions

Molecularly targeted nanocarriers deliver the cytolytic peptide melittin specifically to tumor cells in mice, reducing tumor growth

Communication: Consistent picture of lateral subdiffusion in lipid bilayers: Molecular dynamics simulation and exact results

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