Combined force spectroscopy, AFM and calorimetric studies to reveal the nanostructural organization of biomimetic membranes

Suárez-Germà, Carme; Morros, Antoni; Montero, M. Teresa; Hernández-Borrell, Jordi; Doménech, Òscar

doi:10.1016/j.chemphyslip.2014.07.009

Cited by 5 publications

(9 citation statements)

References 62 publications

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“…However, its magnitude is affected by many factors, including buffer condition, sample preparation protocol, tip selection, and parameters used for force measurements. Large variation of bilayer puncture forces has been reported by different groups (from <1 nN to >10 nN) [39, 40, 44, 45, 66, 69–75]. For the POPC/POPG bilayer in this study, the probability distribution of F P indicates that the most probable F P is 2.8 nN (Fig.…”

Section: Resultssupporting

confidence: 48%

Modulation of lipid membrane structural and mechanical properties by a peptidomimetic derived from reduced amide scaffold

Khadka¹,

Teng²,

Cai³

et al. 2017

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Understanding how antimicrobial peptidomimetics interact with lipid membranes is important in battling multidrug resistant bacterial pathogens. We study the effects of a recently reported peptidomimetic on lipid bilayer structural and mechanical properties. The compound referred to as E107-3 is synthesized based on the acylated reduced amide scaffold and has been shown to exhibit good antimicrobial potency. Our vesicle leakage essay indicates that the compound increases lipid bilayer permeability. We use micropipette aspiration to explore the kinetic response of giant unilamellar vesicles (GUVs). Exposure to the compound causes the GUV protrusion length LP to spontaneously increase and then decrease, followed by GUV rupture. Solution atomic force microscopy (AFM) is used to visualize lipid bilayer structural modulation within a nanoscopic regime. Unlike melittin, which produces pore-like structures, the peptidomimetic compound is found to induce nanoscopic heterogeneous structures. Finally, we use AFM-based force spectroscopy to study the impact of the compound on lipid bilayer mechanical properties. We find that incremental addition of the compound to planar lipid bilayers results in a moderate decrease of the bilayer puncture force FP and a 39% decrease of the bilayer area compressibility modulus KA. To explain our experimental data, we propose a membrane interaction model encompassing disruption of lipid chain packing and extraction of lipid molecules. The later action mode is supported by our observation of a double-bilayer structure in the presence of fusogenic calcium ions.

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Section: Resultssupporting

confidence: 48%

Modulation of lipid membrane structural and mechanical properties by a peptidomimetic derived from reduced amide scaffold

Khadka¹,

Teng²,

Cai³

et al. 2017

Biochimica et Biophysica Acta (BBA) - Biomembranes

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show abstract

“…By pushing the AFM tip through the lipid bilayer, force spectroscopy showed a characteristic 4–5 nm jump in the approach curve (Fig. e), which confirmed the existence of the SLB (Alessandrini and Facci, ; Alessandrini et al, ; Canale et al, ; Franz et al, ; Heath et al, ; Suarez‐Germa et al, ). About 5 min later after adding GO (final concentration of ∼2 µg/mL), a few defects appeared, as highlighted by black arrows in Figures b and c.…”

Section: Resultsmentioning

confidence: 64%

Strong hydrophobic interaction between graphene oxide and supported lipid bilayers revealed by AFM

Lei

Zhang

et al. 2016

Microscopy Res & Technique

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Understanding the interaction between graphene oxide (GO) and lipid membranes is of great importance for its various applications in biotechnology. Here, we investigated the interaction between GO and charged supported lipid bilayers (SLBs) by in situ atomic force microscope (AFM) imaging. It was found that GO could peel off a single layer of positively charged SLBs and deposited on the hydrophobic part of the remaining sublayer. Then free lipid molecules would assemble on GO surface and formed 1.5 bilayers in a lipid-GO-lipid manner. For negatively charged lipid bilayers, however, GO deposited to the SLBs only when its concentration was very high. These results indicate that, in addition to electrostatic interaction, the hydrophobic interaction plays an important role when GO sheets deposit onto the charged lipid bilayers, and should be helpful to understand possible cytotoxicity and antibiosis of graphene-related nanomaterials. Microsc. Res. Tech. 79:721-726, 2016. © 2016 Wiley Periodicals, Inc.

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“…3.6d) because the substrate (usually mica) induces a shift of the T m of the SLBs. In the case of POPE:POPG, a pseudo-binary phase diagram for the SLBs has been constructed from AFM topographic images acquired at different temperatures (Suárez-Germà et al 2014b). The method is based in the calculation of the area covered by the L α and L β phases as e.g.…”

Section: Lateral Segregation Of Imps: Experimental Evidencementioning

confidence: 99%

Lateral Distribution of Membrane Components and Transient Lipid-Protein Structures

Hernández-Borrell

Doménech

Keough

2016

Membrane Protein – Lipid Interactions: Physics and Chemistry in the Bilayer

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The individual physicochemical properties of membrane phospholipids, acyl chain composition and headgroup charge, are major determinants of lipid phase separation into domains. In this chapter we will review the general procedure to reconstitute integral membrane proteins (IMPs) into supported lipid bilayers (SLBs). Second, a brief introduction to lipid phase diagrams is presented. Then we will discuss the wide variety of lipid-protein structures reported in the literature. Protein affinity for lipids is discussed on the basis of temporal and spatial residence of lipids at the lipid-protein boundary, leading to definitions of boundary, associated non-boundary-lipid, and the remainder of lipids that are distributed in the bulk of the bilayer. We present some examples to illustrate the hydrophobic matching between lipids and IMPs, and based on physical properties of the lipid, stretching and bending, we introduce the surface flexible model (SFM) of the membrane which is consistent with the continuum theory of matter applied to membranes. This model accounts for the experimentally observed physicochemical behaviours to interpret the insertion of IMPs into specific lipid domains of the membrane.

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Combined force spectroscopy, AFM and calorimetric studies to reveal the nanostructural organization of biomimetic membranes

Cited by 5 publications

References 62 publications

Modulation of lipid membrane structural and mechanical properties by a peptidomimetic derived from reduced amide scaffold

Modulation of lipid membrane structural and mechanical properties by a peptidomimetic derived from reduced amide scaffold

Strong hydrophobic interaction between graphene oxide and supported lipid bilayers revealed by AFM

Lateral Distribution of Membrane Components and Transient Lipid-Protein Structures

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