Mimic Cell Membranes Research Articles

Photo-Cross-Linked Dual-Responsive Hollow Capsules Mimicking Cell Membrane for Controllable Cargo Post-Encapsulation and Release.

Multifunctional and responsive hollow capsules are ideal candidates to establish highly sophisticated compartments mimicking cell membranes for controllable bio‐inspired functions. For this purpose pH and temperature dual‐responsive and photo‐cross‐linked hollow capsules, based on silica‐templated layer‐by‐layer approach by using poly(N‐isopropyl acrylamide)‐block‐polymethacrylate) and polyallylamine, have been prepared to use them for the subsequent and easily available post‐encapsulation process of protein‐like macromolecules at room temperature and pH 7.4 and their controllable release triggered by stimuli. The uptake and release properties of the hollow capsules for cargos are highly affected by changes in the external stimuli temperature (25, 37, or 45 °C) and internal stimuli pH of the phosphate‐containing buffer solution (5.5 or 7.4), by the degree of photo‐cross‐linking, and the size of cargo. The photo‐cross‐linked and dual stimuli‐responsive hollow capsules with different membrane permeability can be considered as attractive material for mimicking cell functions triggered by controllable uptake and release of different up to 11 nm sized biomolecules.

Upconversion Nanoparticles: Formation of a Supported Lipid Bilayer on Faceted LiYF4:Tm3+/Yb3+ Upconversion Nanoparticles (Part. Part. Syst. Charact. 12/2016)

Supported lipid bilayers mimic cell membranes and may be an alternative method to produce water dispersible nanoparticles with high biocompatibility and provide the possibility of drug encapsulation inside the lipid bilayer. On page 865, J. A. Capobianco and co-workers apply this approach to lanthanide-doped upconverting nanoparticles that convert low energy light (NIR) to UV and visible.

Interaction of Artepillin C with model membranes.

Green propolis, a mixture of beeswax and resinous compounds processed by Apis mellifera, displays several pharmacological properties. Artepillin C, the major compound in green propolis, consists of two prenylated groups bound to a phenyl group. Several studies have focused on the therapeutic effects of Artepillin C, but there is no evidence that it interacts with amphiphilic aggregates to mimic cell membranes. We have experimentally and computationally examined the interaction between Artepillin C and model membranes composed of dimyristoylphosphatidylcholine (DMPC) because phosphatidylcholine (PC) is one of the most abundant phospholipids in eukaryotic cell membranes. PC is located in both outer and inner leaflets and has been used as a simplified membrane model and a non-specific target to study the action of amphiphilic molecules with therapeutic effects. Experimental results indicated that Artepillin C adsorbed onto the DMPC monolayers. Its presence in the lipid suspension pointed to an increased tendency toward unilamellar vesicles and to decreased bilayer thickness. Artepillin C caused point defects in the lipid structure, which eliminated the ripple phase and the pre-transition in thermotropic chain melting. According to molecular dynamics (MD) simulations, (1) Artepillin C aggregated in the aqueous phase before it entered the bilayer; (2) Artepillin C was oriented along the direction normal to the surface; (3) the negatively charged group on Artepillin C was accommodated in the polar region of the membrane; and (4) thinner regions emerged around the Artepillin C molecules. These results help an understanding of the molecular mechanisms underlying the biological action of propolis.

Hydrodynamic Propulsion of Liposomes Electrostatically Attracted to a Lipid Membrane Reveals Size-Dependent Conformational Changes.

The efficiency of lipid nanoparticle uptake across cellular membranes is strongly dependent on the very first interaction step. Detailed understanding of this step is in part hampered by the large heterogeneity in the physicochemical properties of lipid nanoparticles, such as liposomes, making conventional ensemble-averaging methods too blunt to address details of this complex process. Here, we contribute a means to explore whether individual liposomes become deformed upon binding to fluid cell-membrane mimics. This was accomplished by using hydrodynamic forces to control the propulsion of nanoscale liposomes electrostatically attracted to a supported lipid bilayer. In this way, the size of individual liposomes could be determined by simultaneously measuring both their individual drift velocity and diffusivity, revealing that for a radius of ∼45 nm, a close agreement with dynamic light scattering data was observed, while larger liposomes (radius ∼75 nm) displayed a significant deformation unless composed of a gel-phase lipid. The relevance of being able to extract this type of information is discussed in the context of membrane fusion and cellular uptake.

Molecular dynamics investigation of dodecylmaltoside micelle properties.

Micelles are spherical assemblies of detergent molecules that form in aqueous solutions.The hydrophilic head of each molecule faces water on the outside of the sphere and the hydrophobic tail of the molecule points toward the center of the micelle. While detergent micelles are commonly used to mimic cell membranes during experimental work on membrane proteins, their biophysical properties are not well understood at the atomistic level. The present work focuses on all atom molecular dynamics simulations of the detergent molecule dodecylmaltoside (DDM). We have investigated the effects of starting configurations and total number of molecules in the simulation (above and below the aggregation number) using pre- formed micelle arrangements consisting of 60, 80, 100, 130, 150, and 200 DDM molecules and random assortment arrangements of 60, 110, 200, and 220 DDM molecules. Results to be presented include validation of the CHARMM force field for DDM, aggregation number, and radius of gyration.

Experimental evidence for the mode of action based on electrostatic and hydrophobic forces to explain interaction between chitosans and phospholipid Langmuir monolayers

The interaction between chitosans and Langmuir monolayers mimicking cell membranes has been explained with an empirical scheme based on electrostatic and hydrophobic forces, but so far this has been tested only for dimyristoyl phosphatidic acid (DMPA). In this paper, we show that the mode of action in such a scheme is also valid for dipalmitoyl phosphatidyl choline (DPPC) and dipalmitoyl phosphatidyl glycerol (DPPG), whose monolayers were expanded and their compressibility modulus decreased by interacting with chitosans. In general, the effects were stronger for the negatively charged DPPG in comparison to DPPC, and for the low molecular weight chitosan (LMWChi) which was better able to penetrate into the hydrophobic chains than the high molecular weight chitosan (Chi). Penetration into the hydrophobic chains was confirmed with polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) and sum frequency generation (SFG) spectroscopy. A slight reduction in conformational order of the lipid chains induced by the chitosans was quantitatively estimated by measuring the ratio between the intensities of the methyl (r+) and methylene (d+) peaks in the SFG spectra for DPPG. The ratio decreased from 35.6 for the closely packed DPPG monolayer to 7.0 and 6.6 for monolayers containing Chi and LMWChi, respectively. Since in both cases there was a significant phospholipid monolayer expansion, the incorporation of chitosans led to chitosan-rich and lipid-rich condensed domains, which mantained conformational order for their hydrophobic tails. The stronger effects from LMWChi are ascribed to an easier access to the hydrophobic tails, as corroborated by measuring aggregation in solution with dynamic light scattering, where the hydrodynamic radius for LMWChi was close to half of that for Chi. Taken together, the results presented here confirm that the same mode of action applies to different phospholipids that are important constituents of mammalian (DPPC) and bacterial (DPPG) cell membranes.

Characterization of antimicrobial activity against Listeria and cytotoxicity of native melittin and its mutant variants

Antimicrobial peptides (AMPs) are relatively short peptides that have the ability to penetrate the cell membrane, form pores leading to cell death. This study compares both antimicrobial activity and cytotoxicity of native melittin and its two mutants, namely, melittin I17K (GIGAVLKVLTTGLPALKSWIKRKRQQ) with a higher charge and lower hydrophobicity and mutant G1I (IIGAVLKVLTTGLPALISWIKRKRQQ) of higher hydrophobicity. The antimicrobial activity against different strains of Listeria was investigated by bioassay, viability studies, fluorescence and transmission electron microscopy. Cytotoxicity was examined by lactate dehydrogenase (LDH) assay on mammalian Caco-2 cells. The minimum inhibitory concentration of native, mutant I17K, mutant G1I against Listeria monocytogenes F4244 was 0.315±0.008, 0.814±0.006 and 0.494±0.037μg/ml respectively, whereas the minimum bactericidal concentration values were 3.263±0.0034, 7.412±0.017 and 5.366±0.019μg/ml respectively. Lag time for inactivation of L. monocytogenes F4244 was observed at concentrations below 0.20 and 0.78μg/ml for native and mutant melittin I17K respectively. The antimicrobial activity against L. monocytogenes F4244 was in the order native>G1I>I17K. Native melittin was cytotoxic to mammalian Caco-2 cells above concentration of 2μg/ml, whereas the two mutants exhibited negligible cytotoxicity up to a concentration of 8μg/ml. Pore formation in cell wall/membrane was observed by transmission electron microscopy. Molecular dynamics (MD) simulation of native and its mutants indicated that (i) surface native melittin and G1I exhibited higher tendency to penetrate a mimic of bacterial cell membrane and (ii) transmembrane native and I17K formed water channel in mimics of bacterial and mammalian cell membranes.

ChemInform Abstract: Bioinspired Polymer Vesicles and Membranes for Biological and Medical Applications

AbstractReview: 293 refs.

Chondroitin sulfate interacts mainly with headgroups in phospholipid monolayers

Sulfated glycosaminoglycans are precursors of the extracellular matrix used to treat diseases related to blood clotting and degenerative joint diseases. These medical applications have been well established, but the mode of action at the molecular level, which depends on the interaction with cell membranes, is not known in detail. In this study, we investigated the interaction between chondroitin sulfate (CS) and phospholipid monolayers that mimic cell membranes. From surface pressure isotherms and polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), CS was found to interact mainly with the polar groups of dipalmitoyl phosphatidylcholine (DPPC) and dipalmitoyl phosphatidylglycerol (DPPG), with negligible penetration into the hydrophobic tails and only small changes in monolayer elasticity for the packing corresponding to a real cell membrane. The changes in surface pressure and surface potential isotherms depended on CS concentration and on the time allowed for its adsorption onto the monolayer, which points to a dynamic adsorption-desorption process. The charge of the phospholipid was also relevant, since CS induced order into DPPC monolayers while the opposite occurred for DPPG, according to the PM-IRRAS spectra. In summary, interaction with polar groups is responsible for the CS effects on model cell membranes.

Characterisation of the Self-Assemblies Properties and Interaction with Models Membranes of New Type of Amphiphilic Cyclodextrins : A DLS and SS-NMR Study

Thanks to their abilities to form inclusion complexes and nanoparticles with many hydrophobic drugs, cyclodextrins are widely used for vectorization(1). Nevertheless, the poor diffusion of these systems through cell membrane and the low stability of their aggregates remain major obstacles, particularly for pharmaceutical applications(2). To deal with this problem, amphiphilic cyclodextrins are commonly used in the literature(3). This work presents the characterization of the nanoparticles obtained by the aggregation of new types of amphiphilic cyclodextrins(4), lipophosphoramidyl-cyclodextrins and glycerolipidyl-cyclodextrins, as well as the study of their influences on model membranes. Dynamic Light Scattering (DLS) shows that the nanoparticles have a diameter lower than 400nm and stability greater than 14 days. Amphiphilic cyclodextrin/lipid interactions have been studied by 31P and 2H Solid-State NMR (SS-NMR) on multilamellar vesicles (MLV) with different composition used to mimic cell membranes. 31P NMR experiment shows a global insertion of amphiphilic cyclodextrins and 2H NMR data suggest disturbance of the lipid dynamics due to cyclodextrins, which seems to be influenced by the nature of the lipid chains. Indeed, in the case of MLV of DMPC (C14:0), a rigidification has been observed whereas an increase of the lipid dynamics is noted for liposomes constituted by POPC (18:1; 16:0). Finally, results obtained on a third model, POPC-d31/CH/SM (5.2/3.3/1.5), which contains cholesterol and sphingomyelin, two major lipid class found in natural plasma membrane, show also a fluidification.Reference:(1)S. V. Kurkov. & T. Loftsson, International Journal of Pharmaceutics, (2013), 453, 167-180.(2)H. Parrot-Lopez et al., Annales Pharmaceutiques Francaises, (2010), 68, 12-26.(3)V. Bonnet et al., Drug Discovery Today, (2015), 20(9), 1120-1126.(4)C. Gervaise et al., Biochimie, (2012), 94, 66-74.

Biomembrane Fabrication by the Solvent-assisted Lipid Bilayer (SALB) Method

In order to mimic cell membranes, the supported lipid bilayer (SLB) is an attractive platform which enables in vitro investigation of membrane-related processes while conferring biocompatibility and biofunctionality to solid substrates. The spontaneous adsorption and rupture of phospholipid vesicles is the most commonly used method to form SLBs. However, under physiological conditions, vesicle fusion (VF) is limited to only a subset of lipid compositions and solid supports. Here, we describe a one-step general procedure called the solvent-assisted lipid bilayer (SALB) formation method in order to form SLBs which does not require vesicles. The SALB method involves the deposition of lipid molecules onto a solid surface in the presence of water-miscible organic solvents (e.g., isopropanol) and subsequent solvent-exchange with aqueous buffer solution in order to trigger SLB formation. The continuous solvent exchange step enables application of the method in a flow-through configuration suitable for monitoring bilayer formation and subsequent alterations using a wide range of surface-sensitive biosensors. The SALB method can be used to fabricate SLBs on a wide range of hydrophilic solid surfaces, including those which are intractable to vesicle fusion. In addition, it enables fabrication of SLBs composed of lipid compositions which cannot be prepared using the vesicle fusion method. Herein, we compare results obtained with the SALB and conventional vesicle fusion methods on two illustrative hydrophilic surfaces, silicon dioxide and gold. To optimize the experimental conditions for preparation of high quality bilayers prepared via the SALB method, the effect of various parameters, including the type of organic solvent in the deposition step, the rate of solvent exchange, and the lipid concentration is discussed along with troubleshooting tips. Formation of supported membranes containing high fractions of cholesterol is also demonstrated with the SALB method, highlighting the technical capabilities of the SALB technique for a wide range of membrane configurations.

Biomembrane Fabrication by the Solvent-assisted Lipid Bilayer (SALB) Method.

In order to mimic cell membranes, the supported lipid bilayer (SLB) is an attractive platform which enables in vitro investigation of membrane-related processes while conferring biocompatibility and biofunctionality to solid substrates. The spontaneous adsorption and rupture of phospholipid vesicles is the most commonly used method to form SLBs. However, under physiological conditions, vesicle fusion (VF) is limited to only a subset of lipid compositions and solid supports. Here, we describe a one-step general procedure called the solvent-assisted lipid bilayer (SALB) formation method in order to form SLBs which does not require vesicles. The SALB method involves the deposition of lipid molecules onto a solid surface in the presence of water-miscible organic solvents (e.g., isopropanol) and subsequent solvent-exchange with aqueous buffer solution in order to trigger SLB formation. The continuous solvent exchange step enables application of the method in a flow-through configuration suitable for monitoring bilayer formation and subsequent alterations using a wide range of surface-sensitive biosensors. The SALB method can be used to fabricate SLBs on a wide range of hydrophilic solid surfaces, including those which are intractable to vesicle fusion. In addition, it enables fabrication of SLBs composed of lipid compositions which cannot be prepared using the vesicle fusion method. Herein, we compare results obtained with the SALB and conventional vesicle fusion methods on two illustrative hydrophilic surfaces, silicon dioxide and gold. To optimize the experimental conditions for preparation of high quality bilayers prepared via the SALB method, the effect of various parameters, including the type of organic solvent in the deposition step, the rate of solvent exchange, and the lipid concentration is discussed along with troubleshooting tips. Formation of supported membranes containing high fractions of cholesterol is also demonstrated with the SALB method, highlighting the technical capabilities of the SALB technique for a wide range of membrane configurations.

How molecular internal-geometric parameters affect PB-PEO polymersome size in aqueous solution

Amphiphilic polybutadiene polyethylene oxide (PB-PEO) is one of the best known chemistries to form stable vesicular morphologies, stated as polymersomes, in aqueous environment. Mimicking cell membranes, these structures self-assemble in an “amphiphilic window” determined by 0.15 < f < 0.35 where f is the ratio between the hydrophilic block volume and the entire diblock volume. However the polymersome size distribution also depends on molecular weight (Mn) and in order to gain insight on how f and Mn together determine polymersome size, we prepared PB-PEO diblock copolymers with different block lengths and analyzed vesicle morphology via Dynamic light scattering (DLS) and Freeze-fracture transmission electron microscopy (FF-TEM). We found three main regimes: high f / low Mn with polymersomes of mixed diameter, high f / high Mn with mainly large polymersomes and low f, with mainly small polymersomes. In the first region, the polymersomes are highly polydisperse. There is a tendency towards increased diameter with increasing f and Mn. Taken together our findings can help to identify how polymersome self-assembly can be controlled to achieve size distribution specificity alleviating the need for subsequent tuning of size via extrusion. This can pave the way for cost-effective upscaling of polymersome production for biomedical and biomimetic applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 699–708

Molecular Dynamics Study of Pore Formation by Melittin in a 1,2-Dioleoyl-sn-glycero-3-phosphocholine and 1,2-Di(9Z-octadecenoyl)-sn-glycero-3-phospho-(1′-rac-glycerol) Mixed Lipid Bilayer

Melittin is a naturally occurring antimicrobial peptide that has the ability to kill bacterial cells through cell membrane penetration, leading to pore formation. In this investigation, an all-atom molecular dynamics (MD) simulation has been carried out to describe the interaction of two, four, or six peptides placed on the surface of a 3:1 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-di(9Z-octadecenoyl)-sn-glycero-3-phospho-(1′-rac-glycerol) (DOPG) lipid bilayer (a mimic of the bacterial cell membrane) corresponding to protein/lipid (P/L) ratios of 2:96, 4:162, or 6:166, respectively. MD simulation was also carried out for (i) one to eight transmembrane peptides (corresponding P/L ratios of 1:128 to 8:128) in a 3:1 DOPC/DOPG mixed membrane for symmetric as well as asymmetric placement of peptides and (ii) four to eight transmembrane peptides (corresponding to P/L ratios of 4:128 to 8:128) for a pure DOPC lipid bilayer (a mimic of the mammalian cell membrane) for the asymmetric placement of peptide...

Self-assemblied nanocomplexes based on biomimetic amphiphilic chitosan derivatives for protein delivery.

A bio-inspired nanocarrier was developed for protein delivery based on biodegradable amphiphilic chitosan derivative (DCA-PCCs) with hydrophilic cell membrane mimic phosphorylcholine (PC) and hydrophobic deoxycholic acid (DCA) moieties, which was synthesized via the combination of Atherton-Todd reaction and carbodiimide coupling reaction. Using bovine serum albumin (BSA) as model protein, it was found that DCA-PCCs with suitable degree of substitution of PC and DCA moieties can load proteins by forming nanocomplexes via a solvent evaporation method. The physicochemical characteristics of BSA/DCA-PCCs nanocomplexes were investigated by Zetasizer, atomic force microscopy (AFM) and Fourier-transform infrared (FT-IR) spectroscopy. In vitro biological evaluation revealed BSA/DCA-PCCs nanocomplexes as blank DCA-PCCs nanoparticles had excellent cytocompatibility and hemocompatibility mainly due to the presence of cell membrane mimic phosphorylcholine. BSA release results suggested BSA/DCA-PCCs nanocomplexes showed a sustained release behavior following first order exponential decay kinetics. The results indicated DCA-PCCs provided a promising approach for effectively delivering therapeutic proteins.

Droplet Interface Bilayer as Cell Membrane Mimics: Water Permeability Studies

The process of water permeation across lipid membranes has significant implications for cellular physiology and homeostasis, and its study may lead to a greater understanding of the relationship between the structure of lipid bilayer and the role that lipid structure plays in water permeation. We have created a biomimetic artificial membrane, through contact of water droplets in an oil solution containing lipids. Using optical microscopy, we have measured water transport between droplets, as water moves from one droplet to another due to concentration difference. This was assessed as a function of lipid content, structure, and additives, such as cholesterol, which is an essential component of cell membrane. Our results show that cholesterol can increase the activation energy of water permeability several-fold, depending upon the structure of the lipid that makes up the bilayer, thus shedding light on how this singular sterol is vital to control of water movement. We demonstrate that the droplet interface bilayer can be employed as a convenient model membrane to rapidly explore subtle structural effects on bilayer water permeability.

Electrochemical Sensor Based on Ionic Liquid Crystal Modified Carbon Paste Electrode in Presence of Surface Active Agents for Enoxacin Antibacterial Drug

A sensitive electrochemical sensor based on carbon paste and inclusion of ionic liquid crystal [(1-Butyl-1-methylpiperidinium hexafluorophosphate)] in presence of sodium dodecyl sulfate (ILCMCPE…..SDS) for the electrochemical determination of Enoxacin (EN) was prepared. Different ionic liquids were used and compared, namely (1-n-Hexyl-3-methyl imidazolium tetrafluoroborate) (ILMCPE1…..SDS) and (1-Butyl-4-methyl pyridinium tetrafluoroborate) (ILMCPE2…..SDS). The studied ionic liquids mimic cell membranes for their interaction with drug intake through cell membranes. We found that ILCMCPE…..SDS exhibited good electrochemical performances with higher conductivity and lower electron transfer resistance due to the combining effect of high ion conductivity, sensitivity, fast electron transfer, stability and antifouling ability of the ionic liquid crystal. SDS enhanced the preconcentration/accumulation of EN species in the ionic form at the surface. Excellent performance of ILCMCPE…..SDS for the determination of EN in the linear dynamic range of 6.67×10−7 to 2.22×10−5 mol L−1 with a correlation coefficient 0.9998 and LOD 3.28×10−9 mol L−1. Simultaneous determination of binary mixtures dopamine/enoxacin and epinephrine/enoxacin was demonstrated with good peak potentials separations. This method was successfully applied for direct determination of EN in human urine samples with good recovery results. The ILCMCPE…..SDS showed also high reproducibility selectivity and anti -interference ability.

Polysulfide Rejection Layer for High Performance Lithium Sulfur Batteries

Polysulfide (PS) shuttle has been an impediment to the development of lithium-sulfur batteries with high capacity and cycling stability. Previous efforts to mitigate PS shuttle were mainly focused on 1) the suppression of diffusion of dissolved PS out of the cathode by geometrically trapping PS in porous carbons or adsorbing PS on oxides and conducting polymers and 2) protection of the Li anode from reaction with PS by forming a passivation layer on the Li metal surface or a hybrid anode structure.Here, we report a new strategy to remedy the problem using a polymeric polysulfide rejection layer via in situ or ex situ routes. The key concept of this strategy is to form a thin layer which selectively rejects PS anions but permeates lithium ion, mimicking cell membrane. The in situ formed PS rejection layer, which was developed on the sulfur cathode surface from an electrolyte additive during the first discharge, effectively prevented PS shuttle and consequently enhanced discharge capacity and cycling stability owing to an electrochemical equilibrium between the PS-containing cathode electrolyte and the PS rejection layer. In detail, the discharge capacity at the third cycle was 995 mAh g-1 for the cell with the in situ PS rejection layer and 829 mAh g-1 for the reference cell. At the 200th cycle, the PS rejection layer cell delivered a reversible 787 mAh g-1. In contrast, the discharge capacity of the reference cell dropped to 575 mAh g-1after 200 cycles, which was 73% of the discharge capacity of the cell with the PS rejection layer. Using the ex situ formed layer, which exhibited a similar polysulfide rejection behavior as the in situ layer did, the influence of chemical structure of the layer and battery architecture including the layer were investigated. Battery performances were highly dependent on the chemical nature and physical configuration of the layer. In particular, the layer inserted in the interface of cathode and bulk electrolyte phase improved reversible capacity, whereas, that in the interface of anode and bulk electrolyte phase increased cycling efficiency.

Computational study of bacterial membrane disruption by cationic biocides: structural basis for water pore formation.

The development of biocides as disinfectants that do not induce bacterial resistance is crucial to health care since hospital-acquired infections afflict millions of patients every year. Recent experimental studies of a class of cationic biocides based on the phenylene ethynylene backbone, known as OPEs, have revealed that their biocidal activity is accompanied by strong morphology changes to bacterial cell membranes. In vitro studies of bacterial membrane mimics have shown changes to the lipid phase that are dependent on the length and orientation of the cationic moieties on the backbone. This study uses classical molecular dynamics to conduct a comprehensive survey of how oligomers with different chemical structures interact with each other and with a bacterial cell membrane mimic. In particular, the ability of OPEs to disrupt membrane structure is studied as a function of the length of the biocides and the orientation of their cationic moieties along the backbone of the molecule. The simulation results show that the structure of OPEs radically affects their interactions with a lipid bilayer. Biocides with branched cationic groups form trans-membrane water pores regardless of their backbone length, while only 1-1.5 nm of membrane thinning is observed with biocides with cationic groups on their terminal ends. The molecular dynamics simulations provide mechanistic details at the molecular level of the interaction of these biocidal oligomers and the lipid bilayer and corroborate experimental findings regarding observed differences in membrane disruption by OPEs with different chemical structures.

Parvovirus B19 VLP recognizes globoside in supported lipid bilayers

Studies have suggested that the glycosphingolipid globoside (Gb4Cer) is a receptor for human parvovirus B19. Virus-like particles bind to Gb4Cer on thin-layer chromatograms, but a direct interaction between the virus and lipid membrane-associated Gb4Cer has been debated. Here, we characterized the binding of parvovirus B19 VP1/VP2 virus-like particles to glycosphingolipids (i) on thin-layer chromatograms (TLCs) and (ii) incorporated into supported lipid bilayers (SLBs) acting as cell-membrane mimics. The binding specificities of parvovirus B19 determined in the two systems were in good agreement; the VLP recognized both Gb4Cer and the Forssman glycosphingolipid on TLCs and in SLBs compatible with the role of Gb4Cer as a receptor for this virus.