Functionalizing the glycocalyx of living cells with supramolecular guest ligands for cucurbit[8]uril-mediated assembly

2016 ◽  
Vol 52 (44) ◽  
pp. 7146-7149 ◽  
Author(s):  
Emanuela Cavatorta ◽  
Mark L. Verheijden ◽  
Wies van Roosmalen ◽  
Jens Voskuhl ◽  
Jurriaan Huskens ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Living Cells ◽  
Non Fouling

Metabolically presented naphthol ligands on the glycocalyx to trap cells to non-fouling lipid bilayers by heterocomplexation with cucurbit[8]uril and methylviologen.

scholarly journals A Tissue-Like Printed Material

Science ◽  
2013 ◽  
Vol 340 (6128) ◽  
pp. 48-52 ◽  
Author(s):  
Gabriel Villar ◽  
Alexander D. Graham ◽  
Hagan Bayley
Keyword(s):  
Tissue Engineering ◽  
Membrane Proteins ◽  
Lipid Bilayers ◽  
Collective Behavior ◽  
Three Dimensional ◽  
Living Cells ◽  
Emergent Properties ◽  
Living Tissue ◽  
Cohesive Material

Living cells communicate and cooperate to produce the emergent properties of tissues. Synthetic mimics of cells, such as liposomes, are typically incapable of cooperation and therefore cannot readily display sophisticated collective behavior. We printed tens of thousands of picoliter aqueous droplets that become joined by single lipid bilayers to form a cohesive material with cooperating compartments. Three-dimensional structures can be built with heterologous droplets in software-defined arrangements. The droplet networks can be functionalized with membrane proteins; for example, to allow rapid electrical communication along a specific path. The networks can also be programmed by osmolarity gradients to fold into otherwise unattainable designed structures. Printed droplet networks might be interfaced with tissues, used as tissue engineering substrates, or developed as mimics of living tissue.

scholarly journals Direct measurement of DNA-mediated adhesion between lipid bilayers

2015 ◽  
Vol 17 (24) ◽  
pp. 15615-15628 ◽  
Author(s):  
S. F. Shimobayashi ◽  
B. M. Mognetti ◽  
L. Parolini ◽  
D. Orsi ◽  
P. Cicuta ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Direct Measurement ◽  
Living Cells ◽  
Solid Substrates ◽  
Multivalent Interactions

Multivalent interactions between deformable mesoscopic units are ubiquitous in biology, where membrane macromolecules mediate the interactions between neighbouring living cells and between cells and solid substrates.

scholarly journals Nanoparticle-Lipid Interaction: Job Scattering Plots to Differentiate Vesicle Aggregation from Supported Lipid Bilayer Formation

2018 ◽  
Vol 2 (4) ◽  
pp. 50 ◽  
Author(s):  
Fanny Mousseau ◽  
Evdokia Oikonomou ◽  
Victor Baldim ◽  
Stéphane Mornet ◽  
Jean-François Berret
Keyword(s):  
Lipid Bilayers ◽  
Lipid Vesicles ◽  
Living Cells ◽  
Supported Lipid Bilayers ◽  
Supported Lipid Bilayer ◽  
Mixed Aggregates ◽  
Method Of Continuous Variation ◽  
The Impact ◽  
Analytical Expressions ◽  
Lipid Interaction

The impact of nanomaterials on lung fluids, or on the plasma membrane of living cells, has prompted researchers to examine the interactions between nanoparticles and lipid vesicles. Recent studies have shown that nanoparticle-lipid interaction leads to a broad range of structures including supported lipid bilayers (SLB), particles adsorbed at the surface or internalized inside vesicles, and mixed aggregates. Currently, there is a need to have simple protocols that can readily evaluate the structures made from particles and vesicles. Here we apply the method of continuous variation for measuring Job scattering plots and provide analytical expressions for the scattering intensity in various scenarios. The result that emerges from the comparison between experiments and modeling is that electrostatics play a key role in the association, but it is not sufficient to induce the formation of supported lipid bilayers.

scholarly journals Fluorescent conjugates of brefeldin A selectively stain the endoplasmic reticulum and Golgi complex of living cells.

1995 ◽  
Vol 43 (9) ◽  
pp. 907-915 ◽  
Author(s):  
Y Deng ◽  
J R Bennink ◽  
H C Kang ◽  
R P Haugland ◽  
J W Yewdell
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Bilayers ◽  
Golgi Complex ◽  
Intracellular Transport ◽  
Brefeldin A ◽  
Living Cells ◽  
Vesicular Trafficking ◽  
Cellular Functions ◽  
Animal Cells ◽  
Specific Localization

The fungal metabolite brefeldin A (BFA) interferes with vesicular trafficking in most animal cells. To gain insight into the mechanism of BFA action, we esterified it to the fluorophore, boron dipyromethene difluoride (BODIPY). BODIPY-BEA localized predominantly in the endoplasmic reticulum (ER) and Golgi complex of viable cells and was extracted by detergent treatment, suggesting it interacts primarily with lipid bilayers. The localization of the conjugate is conferred by BFA, since free BODIPY or BODIPY esterified to cyclopentanol did not specifically localize to internal membranes. BODIPY-BFA exhibited a similar biological activity to BFA, but only when used at higher concentrations and after a delay. HPLC analysis revealed that over this period, cells converted BODIPY-BFA to species co-eluting with free BODIPY and BFA. Therefore, BODIPY-BFA is probably inactive until BFA is released by cellular esterases. The specific localization of BODIPY-BFA to the ER and Golgi complex suggests that BFA might exert its effects on vesicular trafficking by perturbing the lipid bilayer of its target organelles. Because BODIPY-BFA intensely stains the ER at concentrations that have no discernible effects on intracellular transport or other cellular functions, it should be useful for visualizing the ER in living cells.

scholarly journals Nanoparticle-Lipid Interaction: Job Scattering Plots to Differentiate Vesicle Aggregationfrom Supported Lipid Bilayer Formation

2018 ◽  
Author(s):  
Fanny Mousseau ◽  
Evdokia Oikonomou ◽  
Victor Baldim ◽  
Stéphane Mornet ◽  
Jean-François Berret
Keyword(s):  
Lipid Bilayers ◽  
Lipid Vesicles ◽  
Living Cells ◽  
Supported Lipid Bilayers ◽  
Supported Lipid Bilayer ◽  
Mixed Aggregates ◽  
Method Of Continuous Variation ◽  
The Impact ◽  
Analytical Expressions ◽  
Lipid Interaction

The impact of nanomaterials on lung fluids or on the plasma membrane of living cells has prompted researchers to examine the interactions between nanoparticles and lipid vesicles. Recent studies have shown that nanoparticle-lipid interaction leads to a broad range of structures including supported lipid bilayers (SLB), particles adsorbed at the surface or internalized inside vesicles, and mixed aggregates. Today, there is a need to have simple protocols that can readily assess the nature of structures obtained from particles and vesicles. Here we apply the method of continuous variation for measuring Job scattering plots and provide analytical expressions for the scattering intensity in various scenarios. The result that emerges from the comparison between modeling and experimental measurements is that electrostatics plays a key role in the association, but it is not sufficient to induce the formation of supported lipid bilayers.

Self-Assembly Processes Were Essential for Life’s Origin

2019 ◽  
Author(s):  
David W. Deamer
Keyword(s):  
Lipid Bilayers ◽  
Self Assembly ◽  
Directed Assembly ◽  
Living Cells ◽  
Light Energy ◽  
Ion Concentration ◽  
Future Research ◽  
Lipid Bilayer Membranes ◽  
Bilayer Membranes ◽  
Transmembrane Channels

In the absence of self-assembly processes, life as we know it would be impossible. This chapter begins by introducing self-assembly then focuses on the primary functions of membranes in living cells, most of which depend on highly evolved proteins embedded in lipid bilayers. These serve to capture light energy in photosynthesis and produce ion concentration gradients from which osmotic energy can be transduced into chemical energy. Although lipid bilayer membranes provide a permeability barrier, they cannot be absolutely impermeable because intracellular metabolic functions depend on external sources of nutrients. Therefore, another set of embedded proteins evolved to form transmembrane channels that allow selective permeation of certain solutes. The earliest life did not have proteins available, so in their absence what was the primary function of membranous compartments in prebiotic conditions? There are three possibilities. First, the compartments would allow encapsulated polymers to remain together as random mixtures called protocells. Second, populations of protocells that vary in composition would be subject to selective processes and the first steps of evolution. Even though any given protocell would be only transiently stable, certain mixtures of polymers would tend to stabilize the surrounding membrane. Such an encapsulated mixture would persist longer than the majority that would be dispersed and recycled, and these more robust protocells would tend to emerge as a kind of species. Last and perhaps most important, there had to be a point in early evolution at which light energy began to be captured by membranous structures, just as it is today. Bilayer membranes are not necessarily composed solely of amphiphilic molecules. They can also contain other nonpolar compounds that happen to be pigments capable of capturing light energy. This possibility is almost entirely unexplored, but the experiments are obvious and would be a fruitful focus for future research. Questions to be addressed: What is meant by self-assembly? Why is self-assembly important for the origin of life? What compounds can undergo self-assembly processes? How can mixtures of monomers and lipids assemble into protocells? We tend to think of living cells in terms of directed assembly.

scholarly journals Rhomboid distorts lipids to break the viscosity-imposed speed limit of membrane diffusion

Science ◽  
2019 ◽  
Vol 363 (6426) ◽  
pp. eaao0076 ◽  
Author(s):  
Alex J. B. Kreutzberger ◽  
Ming Ji ◽  
Jesse Aaron ◽  
Ljubica Mihaljević ◽  
Siniša Urban
Keyword(s):  
Lipid Bilayers ◽  
Living Cells ◽  
Speed Limit ◽  
Planar Lipid Bilayers ◽  
Membrane Diffusion ◽  
Intramembrane Proteases ◽  
Cellular Events ◽  
Diffusion Limited ◽  
Viscosity Limit ◽  
Substrate Processing

Enzymes that cut proteins inside membranes regulate diverse cellular events, including cell signaling, homeostasis, and host-pathogen interactions. Adaptations that enable catalysis in this exceptional environment are poorly understood. We visualized single molecules of multiple rhomboid intramembrane proteases and unrelated proteins in living cells (human and Drosophila) and planar lipid bilayers. Notably, only rhomboid proteins were able to diffuse above the Saffman-Delbrück viscosity limit of the membrane. Hydrophobic mismatch with the irregularly shaped rhomboid fold distorted surrounding lipids and propelled rhomboid diffusion. The rate of substrate processing in living cells scaled with rhomboid diffusivity. Thus, intramembrane proteolysis is naturally diffusion-limited, but cells mitigate this constraint by using the rhomboid fold to overcome the “speed limit” of membrane diffusion.

Microfluidic fabrication of cell-derived nanovesicles as endogenous RNA carriers

Lab on a Chip ◽  
2014 ◽  
Vol 14 (7) ◽  
pp. 1261-1269 ◽  
Author(s):  
Wonju Jo ◽  
Dayeong Jeong ◽  
Junho Kim ◽  
Siwoo Cho ◽  
Su Chul Jang ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Lipid Bilayers ◽  
Living Cells ◽  
Plasma Membrane Proteins ◽  
Biological Signal

Artificial exosomes of ~100 nm diameter, enclosed with lipid bilayers, are fabricated from living cells and transfer biological signal components such as encapsulated RNAs and proteins, plasma membrane proteins, or both.

Observation of Concanavalin-A receptors on hydrated planar erythrocyte membrane film by in situ electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 608-609
Author(s):  
Neng-Bo He ◽  
S.W. Hui
Keyword(s):  
Lipid Bilayers ◽  
Erythrocyte Membrane ◽  
Lipid Membranes ◽  
Surface Film ◽  
Biological Membranes ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Black Lipid Membranes ◽  
Fine Mesh ◽  
Planar Films

Monolayers and planar "black" lipid membranes have been widely used as models for studying the structure and properties of biological membranes. Because of the lack of a suitable method to prepare these membranes for electron microscopic observation, their ultrastructure is so far not well understood. A method of forming molecular bilayers over the holes of fine mesh grids was developed by Hui et al. to study hydrated and unsupported lipid bilayers by electron diffraction, and to image phase separated domains by diffraction contrast. We now adapted the method of Pattus et al. of spreading biological membranes vesicles on the air-water interfaces to reconstitute biological membranes into unsupported planar films for electron microscopic study. hemoglobin-free human erythrocyte membrane stroma was prepared by hemolysis. The membranes were spreaded at 20°C on balanced salt solution in a Langmuir trough until a surface pressure of 20 dyne/cm was reached. The surface film was repeatedly washed by passing to adjacent troughs over shallow partitions (fig. 1).

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