Recruitment of receptors at supported lipid bilayers promoted by the multivalent binding of ligand-modified unilamellar vesicles

The development of model systems that mimic biological interactions and allow the control of both receptor and ligand densities, is essential for a molecular understanding of biomolecular processes, such as the recruitment of receptors at interfaces.

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Tuning cell adhesion on supported lipid bilayers via nanoscale geometry

Soft Matter ◽

10.1039/d1sm01407b ◽

2021 ◽

Author(s):

Long Li ◽

Jie Gao ◽

Yingfeng Shao ◽

Fan Song ◽

Jinglei Hu

Keyword(s):

Cell Adhesion ◽

Lipid Bilayers ◽

Model Systems ◽

Supported Lipid Bilayers ◽

Membrane Interface ◽

Receptor Ligand ◽

Ligand Interactions

The adhesion of cells to supported lipid bilayers (SLBs) has been widely used as model systems to study the receptor-ligand interactions that cause the membrane interface. The ligand-functionalized SLBs are...

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Urea-mediated anomalous diffusion in supported lipid bilayers

Interface Focus ◽

10.1098/rsfs.2018.0028 ◽

2018 ◽

Vol 8 (5) ◽

pp. 20180028 ◽

Cited By ~ 1

Author(s):

E. E. Weatherill ◽

H. L. E. Coker ◽

M. R. Cheetham ◽

M. I. Wallace

Keyword(s):

Brownian Motion ◽

Polyethylene Glycol ◽

Lipid Bilayer ◽

Lipid Bilayers ◽

Anomalous Diffusion ◽

Incubation Time ◽

Time Scale ◽

Biological Membranes ◽

Model Systems ◽

Supported Lipid Bilayers

Diffusion in biological membranes is seldom simply Brownian motion; instead, the rate of diffusion is dependent on the time scale of observation and so is often described as anomalous. In order to help better understand this phenomenon, model systems are needed where the anomalous diffusion of the lipid bilayer can be tuned and quantified. We recently demonstrated one such model by controlling the excluded area fraction in supported lipid bilayers (SLBs) through the incorporation of lipids derivatized with polyethylene glycol. Here, we extend this work, using urea to induce anomalous diffusion in SLBs. By tuning incubation time and urea concentration, we produce bilayers that exhibit anomalous behaviour on the same scale as that observed in biological membranes.

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Structure, Formation, and Biological Interactions of Supported Lipid Bilayers (SLB) Incorporating Lipopolysaccharide

Coatings ◽

10.3390/coatings10100981 ◽

2020 ◽

Vol 10 (10) ◽

pp. 981

Author(s):

Palak Sondhi ◽

Dhanbir Lingden ◽

Keith J. Stine

Keyword(s):

Lipid Bilayers ◽

Lipid Membranes ◽

Lipid Membrane ◽

Biologically Active ◽

Supported Lipid Bilayers ◽

Biological Interactions ◽

Relevant Model ◽

Biologically Relevant ◽

Model Lipid Membranes ◽

Biomimetic Membrane

Biomimetic membrane systems play a crucial role in the field of biosensor engineering. Over the years, significant progress has been achieved creating artificial membranes by various strategies from vesicle fusion to Langmuir transfer approaches to meet an ever-growing demand for supported lipid bilayers on various substrates such as glass, mica, gold, polymer cushions, and many more. This paper reviews the diversity seen in the preparation of biologically relevant model lipid membranes which includes monolayers and bilayers of phospholipid and other crucial components such as proteins, characterization techniques, changes in the physical properties of the membranes during molecular interactions and the dynamics of the lipid membrane with biologically active molecules with special emphasis on lipopolysaccharides (LPS).

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Calcium Signaling in T Cells Is Induced by Binding to Nickel-Chelating Lipids in Supported Lipid Bilayers

Frontiers in Physiology ◽

10.3389/fphys.2020.613367 ◽

2021 ◽

Vol 11 ◽

Author(s):

Tommy Dam ◽

Victoria Junghans ◽

Jane Humphrey ◽

Manto Chouliara ◽

Peter Jönsson

Keyword(s):

T Cells ◽

T Cell ◽

Calcium Signaling ◽

Lipid Bilayers ◽

Cell Activation ◽

Molecular Mechanisms ◽

Cell Receptor ◽

Model Systems ◽

Supported Lipid Bilayers ◽

Ligand Free

Supported lipid bilayers (SLBs) are one of the most common cell-membrane model systems to study cell-cell interactions. Nickel-chelating lipids are frequently used to functionalize the SLB with polyhistidine-tagged ligands. We show here that these lipids by themselves can induce calcium signaling in T cells, also when having protein ligands on the SLB. This is important to avoid “false” signaling events in cell studies with SLBs, but also to better understand the molecular mechanisms involved in T-cell signaling. Jurkat T cells transfected with the non-signaling molecule rat CD48 were found to bind to ligand-free SLBs containing ≥2 wt% nickel-chelating lipids upon which calcium signaling was induced. This signaling fraction steadily increased from 24 to 60% when increasing the amount of nickel-chelating lipids from 2 to 10 wt%. Both the signaling fraction and signaling time did not change significantly compared to ligand-free SLBs when adding the CD48-ligand rat CD2 to the SLB. Blocking the SLB with bovine serum albumin reduced the signaling fraction to 11%, while preserving CD2 binding and the exclusion of the phosphatase CD45 from the cell-SLB contacts. Thus, CD45 exclusion alone was not sufficient to result in calcium signaling. In addition, more cells signaled on ligand-free SLBs with copper-chelating lipids instead of nickel-chelating lipids and the signaling was found to be predominantly via T-cell receptor (TCR) triggering. Hence, it is possible that the nickel-chelating lipids act as ligands to the cell’s TCRs, an interaction that needs to be blocked to avoid unwanted cell activation.

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Influence of Brain Gangliosides on the Formation and Properties of Supported Lipid Bilayers for Binding Kinetics Studies

10.26434/chemrxiv.7505330 ◽

2018 ◽

Author(s):

Luke Jordan ◽

Nathan Wittenberg

Keyword(s):

Lipid Bilayers ◽

Binding Kinetics ◽

Supported Lipid Bilayers ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Supported Lipid Bilayer ◽

Head Groups ◽

Lipid Diffusion ◽

Kinetics Of ◽

Brain Gangliosides

This is a comprehensive study of the effects of the four major brain gangliosides (GM1, GD1b, GD1a, and GT1b) on the adsorption and rupture of phospholipid vesicles on SiO2 surfaces for the formation of supported lipid bilayer (SLB) membranes. Using quartz crystal microbalance with dissipation monitoring (QCM-D) we show that gangliosides GD1a and GT1b significantly slow the SLB formation process, whereas GM1 and GD1b have smaller effects. This is likely due to the net ganglioside charge as well as the positions of acidic sugar groups on ganglioside glycan head groups. Data is included that shows calcium can accelerate the formation of ganglioside-rich SLBs. Using fluorescence recovery after photobleaching (FRAP) we also show that the presence of gangliosides significantly reduces lipid diffusion coefficients in SLBs in a concentration-dependent manner. Finally, using QCM-D and GD1a-rich SLB membranes we measure the binding kinetics of an anti-GD1a antibody that has similarities to a monoclonal antibody that is a hallmark of a variant of Guillain-Barre syndrome.

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