Cholesterol induced asymmetry in DOPC bilayers probed by AFM force spectroscopy

Adhyapak, Pranav; Panchal, Suresh; Murthy, Appala Venkata Ramana

doi:10.1016/j.bbamem.2018.01.021

Cited by 22 publications

(25 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…∆V-A isotherms provide further detail on the ion specific interactions with CHOL. Our results show that the condensation of lipids in the presence of CHOL depends on the combined action of ions and CHOL, which can alter the physical state of the monolayer.Coatings 2019, 9, 474 2 of 16 strength of the membrane and inducing a non-ideal behavior in mixed systems (known as condensing effect) [9,13]. This non-ideal behavior was firstly observed by Leathes in 1925 who studied mixtures of CHOL and egg lecithin monolayers [14].…”

mentioning

confidence: 93%

“…Coatings 2019, 9, 474 2 of 16 strength of the membrane and inducing a non-ideal behavior in mixed systems (known as condensing effect) [9,13]. This non-ideal behavior was firstly observed by Leathes in 1925 who studied mixtures of CHOL and egg lecithin monolayers [14].…”

mentioning

confidence: 93%

“…The fundamental functions of the CHOL include cellular processes by interacting with other lipids and proteins in the membrane. As a consequence, CHOL has been extensively studied since the late 18th century until present [1][2][3][4][9][10][11][12][13]. In contrast to phospholipids (formed by a larger hydrophilic head and a longer, flexible hydrocarbon tails), CHOL presents a peculiar structure.…”

Section: Introductionmentioning

confidence: 99%

“…Accordingly, CHOL concentration facilitates the phase separation and reduces the mechanical resistance to rupture of coexisting phases in bilayer models of the MFGM. CHOL strongly affects the organization of the MFGM lipid monolayers by condensing the polar lipid molecules, decreasing the difference in height between domains on non-condensed phases and promoting the formation of numerous small domains in the condensed phase.In addition to the above mentioned studies of Langmuir Films, Atomic Force Microscopy (AFM) and Brewster Angle Microscopy (BAM) are complementary techniques that are vastly employed in the studies of lipid-CHOL interactions [13,24,25,28,34]. Although these techniques provide a direct correlation between the topography and force mapping, the exact mechanism of the interaction of CHOL with the individual lipids is not yet fully understood.…”

mentioning

confidence: 99%

“…In addition to the above mentioned studies of Langmuir Films, Atomic Force Microscopy (AFM) and Brewster Angle Microscopy (BAM) are complementary techniques that are vastly employed in the studies of lipid-CHOL interactions [13,24,25,28,34]. Although these techniques provide a direct correlation between the topography and force mapping, the exact mechanism of the interaction of CHOL with the individual lipids is not yet fully understood.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Condensation of Model Lipid Films by Cholesterol: Specific Ion Effects

2019

View full text Add to dashboard Cite

The condensing effect and the ability of cholesterol (CHOL) to induce ordering in lipid films is a question of relevance in biological membranes such as the milk fat globule membrane (MFGM) in which the amount of CHOL influences the phase separation and mechanical resistance to rupture of coexisting phases relevant to emulsified food systems. Here, we study the effect of different salts (NaCl, CaCl 2 , MgCl 2 , LaCl 3 ) on monolayers made of a model mixture of lipids (DPPC:DPPS 4:1) and CHOL. To this end, we apply Langmuir Film Balance to report a combined analysis of surface pressure-area (π-A) and surface potential-area (∆V-A) isotherms along with Micro-Brewster Angle Microscopy (Micro-BAM) images of the monolayers in the presence of the different electrolytes. We show that the condensation of lipid by CHOL depends strongly on the nature of the ions by altering the shape and features of the π-A isotherms. ∆V-A isotherms provide further detail on the ion specific interactions with CHOL. Our results show that the condensation of lipids in the presence of CHOL depends on the combined action of ions and CHOL, which can alter the physical state of the monolayer.Coatings 2019, 9, 474 2 of 16 strength of the membrane and inducing a non-ideal behavior in mixed systems (known as condensing effect) [9,13]. This non-ideal behavior was firstly observed by Leathes in 1925 who studied mixtures of CHOL and egg lecithin monolayers [14]. Therein, it was proved that the average area per molecule in mixtures was much lower than what would be expected from the individual components. Since then, the condensing effect and the ability of CHOL to induce ordering within the hydrocarbon chain of many lipid films, has been extensively characterized using Langmuir films [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. For instance, this technique has been used to bring new insight into the functional role of CHOL in milk polar lipids, used in the preparation of dairy emulsions, e.g., infant milk formulas. In particular, the role played by CHOL in the organization of biological membranes surrounding lipid droplets in milk, called the milk fat globule membrane (MFGM), has been recently investigated [30][31][32][33]. Accordingly, CHOL concentration facilitates the phase separation and reduces the mechanical resistance to rupture of coexisting phases in bilayer models of the MFGM. CHOL strongly affects the organization of the MFGM lipid monolayers by condensing the polar lipid molecules, decreasing the difference in height between domains on non-condensed phases and promoting the formation of numerous small domains in the condensed phase.In addition to the above mentioned studies of Langmuir Films, Atomic Force Microscopy (AFM) and Brewster Angle Microscopy (BAM) are complementary techniques that are vastly employed in the studies of lipid-CHOL interactions [13,24,25,28,34]. Although these techniques provide a direct correlation between the topography and force mapping, the exact mechanism of the interaction of CHOL with the indi...

show abstract

mentioning

confidence: 93%

mentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Condensation of Model Lipid Films by Cholesterol: Specific Ion Effects

2019

View full text Add to dashboard Cite

show abstract

Cholesterol and Melatonin Exert Opposite Effects on the Interaction of Model DMPC Membranes with the SARS‐CoV‐2 S‐Protein: A SANS Study

Булавин

Soloviov²,

Ivankov

et al. 2023

Macromolecular Symposia

View full text Add to dashboard Cite

An effect of receptor-binding domain (RBD) of SARS-CoV-2 S-protein on structural parameters of model lipid membranes presented by dimyristoylphosphatidylcholine (DMPC) systems with cholesterol and melatonin impurities is studied by small angle neutron scattering (SANS). It is shown that an increase in melatonin concentration in the lipid membrane leads to a decrease in the thickness of the lipid bilayer, while an increase in the concentration of cholesterol leads to an increase in its thickness. It is suggested that increasing the concentration of melatonin in a membrane prevents the interaction of coronaviral S-protein with a lipid membrane of a cell. In the presence of cholesterol in the system, the interaction of a lipid membrane with an active part of S-protein occurs depending on a phase state of the lipid: in the case of a gel phase, there is no changes in structural parameters, but at higher temperatures in the case of a liquid crystal phase, an addition of RBD SARS-CoV-2 to the system causes a reduce in the membrane thickness.

show abstract

Solvent‐Assisted Lipid Bilayer Formation on Au Surfaces: Effect of Lipid Concentration on Solid‐Supported Membrane Formation

Neupane

Betlem

Renner

et al. 2021

Physica Status Solidi (a)

View full text Add to dashboard Cite

Solvent-assisted lipid bilayer (SALB) formation has emerged as a versatile approach in forming supported lipid membranes (SLBs) on metal surfaces, interesting platforms for transducing a biological signal to an electrical readout where vesicle rupture is not straightforward. In this work, the effect of the lipid concentration in the organic solvent, a key parameter controlling SALB, is addressed in the low and high concentration limits of DPPC lipid on a Au surface.Quartz crystal microbalance with dissipation (QCM-D) responses are correlated with atomic force microscopy (AFM) topographic and nanomechanical measurements. Upon SALB completion at both concentrations, QCM-D and AFM topographical characterization suggest the formation of thin, although incomplete, lipid layers at the Au-liquid interface, with frequency and dissipation plateau values departing from well-established homogeneous SLB responses. Nanomechanical analysis reveals the presence of mostly monolayers at low concentration due to lack of lipid material, while at high concentration, excess of lipid material leads to coexistence of diverse structures. Their formation stems from the SALB formation mechanism, based on lyotropic transformations upon solvent exchange, which differs from customarily vesicle rupture. Such mechanism leads to peculiar two-step features in approach force curves on SLBs pointing towards a decoupling in bilayer leaflets when supported.

show abstract

Cholesterol induced asymmetry in DOPC bilayers probed by AFM force spectroscopy

Cited by 22 publications

References 38 publications

Condensation of Model Lipid Films by Cholesterol: Specific Ion Effects

Condensation of Model Lipid Films by Cholesterol: Specific Ion Effects

Cholesterol and Melatonin Exert Opposite Effects on the Interaction of Model DMPC Membranes with the SARS‐CoV‐2 S‐Protein: A SANS Study

Solvent‐Assisted Lipid Bilayer Formation on Au Surfaces: Effect of Lipid Concentration on Solid‐Supported Membrane Formation

Contact Info

Product

Resources

About