scholarly journals Formation of Giant Lipid Vesicles in the Presence of Nonelectrolytes—Glucose, Sucrose, Sorbitol and Ethanol

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 945
Author(s):  
Qiong Wang ◽  
Ning Hu ◽  
Jincan Lei ◽  
Qiurong Qing ◽  
Jing Huang ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Cell Membrane ◽  
Lipid Membranes ◽  
Volume Fraction ◽  
Hydrodynamic Force ◽  
Lipid Vesicles ◽  
Ethanol Solution ◽  
Sugar Solution ◽  
Ethanol Content ◽  
Membrane Models

Lipid vesicles, especially giant lipid vesicles (GLVs), are usually adopted as cell membrane models and their preparation has been widely studied. However, the effects of some nonelectrolytes on GLV formation have not been specifically studied so far. In this paper, the effects of the nonelectrolytes, including sucrose, glucose, sorbitol and ethanol, and their coexistence with sodium chloride, on the lipid hydration and GLV formation were investigated. With the hydration method, it was found that the sucrose, glucose and sorbitol showed almost the same effect. Their presence in the medium enhanced the hydrodynamic force on the lipid membranes, promoting the GLV formation. GLV formation was also promoted by the presence of ethanol with ethanol volume fraction in the range of 0 to 20 percent, but higher ethanol content resulted in failure of GLV formation. However, the participation of sodium chloride in sugar solution and ethanol solution stabilized the lipid membranes, suppressing the GLV formation. In addition, the ethanol and the sodium chloride showed the completely opposite effects on lipid hydration. These results could provide some suggestions for the efficient preparation of GLVs.

scholarly journals Development of Artificial Cell Models Using Microfluidic Technology and Synthetic Biology

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 559 ◽  
Author(s):  
Koki Kamiya
Keyword(s):  
Synthetic Biology ◽  
Cell Membrane ◽  
Lipid Bilayer ◽  
Lipid Membranes ◽  
Lipid Vesicles ◽  
Optical Microscope ◽  
Living Cells ◽  
Biochemical Properties ◽  
Cell Models ◽  
Artificial Cell

Giant lipid vesicles or liposomes are primarily composed of phospholipids and form a lipid bilayer structurally similar to that of the cell membrane. These vesicles, like living cells, are 5–100 μm in diameter and can be easily observed using an optical microscope. As their biophysical and biochemical properties are similar to those of the cell membrane, they serve as model cell membranes for the investigation of the biophysical or biochemical properties of the lipid bilayer, as well as its dynamics and structure. Investigation of membrane protein functions and enzyme reactions has revealed the presence of soluble or membrane proteins integrated in the giant lipid vesicles. Recent developments in microfluidic technologies and synthetic biology have enabled the development of well-defined artificial cell models with complex reactions based on the giant lipid vesicles. In this review, using microfluidics, the formations of giant lipid vesicles with asymmetric lipid membranes or complex structures have been described. Subsequently, the roles of these biomaterials in the creation of artificial cell models including nanopores, ion channels, and other membrane and soluble proteins have been discussed. Finally, the complex biological functions of giant lipid vesicles reconstituted with various types of biomolecules has been communicated. These complex artificial cell models contribute to the production of minimal cells or protocells for generating valuable or rare biomolecules and communicating between living cells and artificial cell models.

Quantum dot effects upon the interaction between porphyrins and phospholipids in cell membrane models

2015 ◽  
Vol 45 (3) ◽  
pp. 219-227 ◽  
Author(s):  
Gustavo G. Parra ◽  
Galina Borissevitch ◽  
Iouri Borissevitch ◽  
Ana P. Ramos
Keyword(s):  
Cell Membrane ◽  
Quantum Dot ◽  
Membrane Models

scholarly journals Calibration of LACIS as a CCN detector and its use in measuring activation and hygroscopic growth of atmospheric aerosol particles

2006 ◽  
Vol 6 (12) ◽  
pp. 4519-4527 ◽  
Author(s):  
H. Wex ◽  
A. Kiselev ◽  
M. Ziese ◽  
F. Stratmann
Keyword(s):  
Sodium Chloride ◽  
Wall Temperature ◽  
Atmospheric Aerosol ◽  
Volume Fraction ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Urban Aerosol ◽  
Hygroscopic Growth ◽  
Atmospheric Aerosol Particles ◽  
Droplet Activation

Abstract. A calibration for LACIS (Leipzig Aerosol Cloud Interaction Simulator) for its use as a CCN (cloud condensation nuclei) detector has been developed. For this purpose, sodium chloride and ammonium sulfate particles of known sizes were generated and their grown sizes were detected at the LACIS outlet. From these signals, the effective critical super-saturation was derived as a function of the LACIS wall temperature. With this, LACIS is calibrated for its use as a CCN detector. The applicability of LACIS for measurements of the droplet activation, and also of the hygroscopic growth of atmospheric aerosol particles was tested. The activation of the urban aerosol particles used in the measurements was found to occur at a critical super-saturation of 0.46% for particles with a dry diameter of 75 nm, and at 0.42% for 85 nm, respectively. Hygroscopic growth was measured for atmospheric aerosol particles with dry diameters of 150, 300 and 350 nm at relative humidities of 98 and 99%, and it was found that the larger dry particles contained a larger soluble volume fraction of about 0.85, compared to about 0.6 for the 150 nm particles.

scholarly journals The interplay between lipids and dopamine on α-synuclein oligomerization and membrane binding

2013 ◽  
Vol 33 (5) ◽  
Author(s):  
Chi L. L. Pham ◽  
Roberto Cappai
Keyword(s):  
Lipid Membranes ◽  
Amyloid Fibrils ◽  
Lipid Membrane ◽  
Hydrophobic Interactions ◽  
Membrane Integrity ◽  
Lipid Vesicles ◽  
Helical Conformation ◽  
Unfolded Protein ◽  
Natively Unfolded Protein ◽  
Natively Unfolded

The deposition of α-syn (α-synuclein) as amyloid fibrils and the selective loss of DA (dopamine) containing neurons in the substantia nigra are two key features of PD (Parkinson's disease). α-syn is a natively unfolded protein and adopts an α-helical conformation upon binding to lipid membrane. Oligomeric species of α-syn have been proposed to be the pathogenic species associated with PD because they can bind lipid membranes and disrupt membrane integrity. DA is readily oxidized to generate reactive intermediates and ROS (reactive oxygen species) and in the presence of DA, α-syn form of SDS-resistant soluble oligomers. It is postulated that the formation of the α-syn:DA oligomers involves the cross-linking of DA-melanin with α-syn, via covalent linkage, hydrogen and hydrophobic interactions. We investigate the effect of lipids on DA-induced α-syn oligomerization and studied the ability of α-syn:DA oligomers to interact with lipids vesicles. Our results show that the interaction of α-syn with lipids inhibits the formation of DA-induced α-syn oligomers. Moreover, the α-syn:DA oligomer cannot interact with lipid vesicles or cause membrane permeability. Thus, the formation of α-syn:DA oligomers may alter the actions of α-syn which require membrane association, leading to disruption of its normal cellular function.

scholarly journals Conductivity Study of DTAB in Water and Ethanol-Water Mixture in the Presence and Absence of ZnSO4

2020 ◽  
Vol 17 (4) ◽  
pp. 1207
Author(s):  
Sangita Acharya ◽  
Tulasi Niraula ◽  
Ajaya Bhattarai
Keyword(s):  
Free Energy ◽  
Critical Micelle Concentration ◽  
Volume Fraction ◽  
Standard Free Energy ◽  
Water Mixture ◽  
Dodecyltrimethylammonium Bromide ◽  
Degree Of Dissociation ◽  
Ethanol Content ◽  
Presence And Absence ◽  
Free Energy Of Micellization

The physicochemical behaviour of dodecyltrimethylammonium bromide (DTAB) in water and ethanol-water mixture in the presence and absence of ZnSO4 were studied by measuring the conductivity at 298.15 K. The pre-micellar (S1) and post-micellar slopes (S2) were obtained and calculated the degree of dissociation (α) and the critical micelle concentration (cmc). With an increase in ethanol content, the cmc and α of DTAB increased whereas, in the presence of ZnSO4, the cmc and α decreased. By using cmc and α, thermodynamic properties as the standard free energy of micellization ( ) were evaluated. With an increase in ethanol content, the negative values of  are decreased indicating less spontaneous in the micellization which makes micellization less favourable. The correlation of the pre-micellar and post-micellar slopes with the volume fraction of ethanol were discussed. DTAB micellization was tested in contexts of specific solvent parameters and solvophobic parameter.

Adhesion of Lipid Membranes Mediated by Electrostatic and Specific Interactions

1997 ◽  
Vol 489 ◽  
Author(s):  
Christian W. Maier ◽  
Almuth Behrisch ◽  
Annette Kloboucek ◽  
Rudolf Merkel
Keyword(s):  
Lipid Membranes ◽  
Cell Adhesion Molecule ◽  
Lipid Vesicles ◽  
Membrane Properties ◽  
Specific Cell ◽  
Receptor Aggregation ◽  
Host Membrane ◽  
Aspiration Technique ◽  
Membrane Adhesion ◽  
Positively Charged

AbstractWe used the micropipet aspiration technique for a study of biomembrane adhesion. Adhesion was caused by contact site A, a highly specific cell adhesion molecule, reconstituted in lipid vesicles of DOPC with 5 %(mol/mol) DOPE-PEG2000. We found adhesion and subsequent receptor aggregation in the contact zone. Additionally, electrostatic modulation of membrane adhesion was studied. Whereas addition of the negatively charged lipid SOPS to the lecithin (SOPC) host membrane suppressed adhesion due to electrostatic repulsion, a positively charged lipid (DOTAP) was surprisingly ineffective. This might be due to either phase separation of the mixture or DOTAP changing other membrane properties as bending stiffness and the Hamaker constant.

scholarly journals Antituberculosis Drug Interactions with Membranes: A Biophysical Approach Applied to Bedaquiline

Membranes ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 141
Author(s):  
Marina Pinheiro ◽  
Heinz Amenitsch ◽  
Salette Reis
Keyword(s):  
Cell Membrane ◽  
Eukaryotic Cell ◽  
Membrane Model ◽  
Molar Ratio ◽  
X Ray ◽  
X Ray Scattering ◽  
Membrane Models ◽  
Bacterial Cell Membrane ◽  
Cell Membrane Model ◽  
Ray Scattering

This work focuses on the interaction of the novel and representative antituberculosis (anti-TB) drug bedaquiline (BDQ) with different membrane models of eukaryotic and prokaryotic cells. The effect of BDQ on eukaryotic cell membrane models was assessed using liposomes, namely, multilamellar vesicles (MLVs) made of 1,2-dimyristoyl-rac-glycero-3-phosphocholine (DMPC) and also a mixture of DMPC and cholesterol (CHOL) (8:2 molar ratio). To mimic the prokaryotic cell membrane, 1,2-dimyristoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DMPG) and 1,1′2,2′-tetra-oleoyl-cardiolipin (TOCL) were chosen. Powerful biophysical techniques were employed, including small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS), to understand the effect of BDQ on the nanostructure of the membrane models. The results showed that BDQ demonstrated a pronounced disordering effect in the bacterial cell membrane models, especially in the membrane model with cardiolipin (CL), while the human cell membrane model with large fractions of neutral phospholipids remained less affected. The membrane models and techniques provide detailed information about different aspects of the drug–membrane interaction, thus offering valuable information to better understand the effect of BDQ on their target membrane-associated enzyme as well as its side effects on the cardiovascular system.

27 SODIUM CHLORIDE TREATMENT OF CELL MEMBRANE-PERMEABILIZED NUCLEAR DONOR CELLS FACILITATES THE DISPLACEMENT OF THE SOMATIC HISTONE H1 AND HMG-17 PROTEINS IN RECONSTRUCTED PORCINE EMBRYOS

2006 ◽  
Vol 18 (2) ◽  
pp. 122
Author(s):  
L. Che ◽  
V. Bordignon
Keyword(s):  
Sodium Chloride ◽  
Cell Membrane ◽  
Chromatin Structure ◽  
Nuclear Transfer ◽  
Chromatin Binding ◽  
Salt Extraction ◽  
Reconstructed Embryos ◽  
High Order Chromatin Structure ◽  
Donor Cells ◽  
High Order Chromatin

Developmental efficiency of somatic cell-reconstructed embryos depends on extensive remodeling of chromatin structural components. Due to their importance for maintaining the high-order chromatin structure and controlling DNA functions, including replication, transcription, repair, and recombination, histones and other chromatin-binding proteins represent leading choice markers to investigate nuclear remodeling in reconstructed embryos. The main objective of this study was to investigate whether or not the exposure of cell membrane permeabilized nuclear donor cells to sodium chloride (salt-extraction) would facilitate the displacement of chromatin-binding proteins in reconstructed porcine embryos. Both linker histone H1 (H1) and high-mobility group (HMG) proteins are known to affect gene expression through the modulation of the high-order chromatin structure. Standard methods of oocyte enucleation and electrofusion were applied for embryo reconstruction using in vitro-matured oocytes and control or salt-extracted fetal fibroblast cells. For salt-extraction, confluent cell cultures were washed with Ca2+/Mg2+-free Hank's balanced salt solution (HBSS); cells were permeabilized by incubation with 1 µg/mL of streptolysin O at 37°C for 30 min in HBSS, and then maintained in Tris-NaCl buffer (10 mM Tris-HCl, 0.5 mM MgCl2, 0.7 M NaCl, 1 M sucrose) for 5 min. After salt-extraction, cells were rinsed and cultured in DMEM supplemented with 10% fetal bovine serum (FBS) and 2 mM CaCl2 for 1 h at 37.5°C for membrane resealing prior to nuclear transfer. Reconstructed embryos were activated using ionomycin (15 µM/5 min) and strontium chloride (Sr2+; 10 mM/4 h), and then cultured in PZM-3 medium. Immunostaining for H1 and HMG-17 was performed in nuclear donor cells and embryos at different stages after reconstruction. The time required for H1 displacement in transplanted nuclei was reduced by the salt-extraction treatment (Table 1). Salt-extracted cells showed a stronger HMG-17 cytoplasmic signal compared to control cells. The proportion of HMG-17-positive reconstructed embryos at 1, 3, and 6 h was 54 vs. 19, 57 vs. 44, and 75 vs. 62, for control and salt-extracted cells, respectively. These data suggest that salt-extraction prior to nuclear transplantation enhances the remodeling of chromatin structure in embryos reconstructed with somatic cell nuclei. Table 1. Proportion (n) of H1-positive stained embryos after different times from parthenogenetic activation (PA) and nuclear transfer using control (NT-control) or salt-extracted (NT-extracted) cells This work was supported by a NSERC Discovery Grant to VB.

COMPRESSIVE MECHANICAL PROPERTIES OF POROUS TI-6AL-4V WITH PALM STEARIN BINDER SYSTEM

2015 ◽  
Vol 76 (6) ◽  
Author(s):  
N. H. Mohamad Nor ◽  
J.B Saedon ◽  
N. A. A. Kasim ◽  
M. H. Ismail ◽  
Hazran Husain
Keyword(s):  
Mechanical Properties ◽  
Sodium Chloride ◽  
Volume Fraction ◽  
Young Modulus ◽  
Palm Stearin ◽  
Binder System ◽  
Water Leaching ◽  
Space Holder ◽  
Porous Ti ◽  
Different Temperatures

Most Ti-6Al-4V implant used today are often much stiffer than human bone. However, the young modulus of those Ti-6Al-4V implants can be reduced through the formation of porous structure. Palm stearin binder system with an addition of sodium chloride as space holder has been established in the fabrication of porous Ti-6Al-4V. Thus, this paper focuses on the compressive mechanical properties of porous Ti-6Al-4V with utilization of palm stearin binder system along with sodium chloride (NaCl) as the space holder. The evaluated compositions consist of the powder volume fraction of 63vol% and 65vol%. The samples were compacted by thermal compacting machine at temperature of 160oC. Two different debinding processes involved, which are heptane solvent and water leaching. Then the samples were sintered up to three different temperatures, which are 1200oC, 1250oC and 1300oC. Mechanical properties of the porous Ti-6Al-4V were characterized by axial compression testing. The maximum compressive stress and Young’s modulus of the samples were determined to be 403.87MPa and 9.92GPa.

scholarly journals Quantitative capabilities of STXM to measure spatially resolved organic volume fractions of mixed organic ∕ inorganic particles

2019 ◽  
Vol 12 (3) ◽  
pp. 1619-1633
Author(s):  
Matthew Fraund ◽  
Tim Park ◽  
Lin Yao ◽  
Daniel Bonanno ◽  
Don Q. Pham ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Ammonium Sulfate ◽  
Volume Fraction ◽  
Equal Mass ◽  
Three Solutions ◽  
Inorganic Particles ◽  
X Ray ◽  
Spatially Resolved ◽  
Nexafs Spectroscopy ◽  
Scanning Transmission

Abstract. Scanning transmission X-ray microscopy coupled with near-edge X-ray absorption and fine structure (STXM-NEXAFS) spectroscopy can be used to characterize the morphology and composition of aerosol particles. Here, two inorganic ∕ organic systems are used to validate the calculation of organic volume fraction (OVF) and determine the level of associated error by using carbon K-edge STXM data at 278, 285.4, 288.6, and 320 eV. Using the mixture of sodium chloride and sucrose as one system and ammonium sulfate and sucrose as another, three solutions were made with 10:1, 1:1, and 1:10 mass ratios (inorganic to organic). The OVFs of the organic-rich aerosols of both systems deviated from the bulk OVF by less than 1%, while the inorganic-rich aerosols deviated by approximately 1 %. Aerosols from the equal mass mixture deviated more (about 4 %) due to thick inorganic regions exceeding the linear range of Beer's law. These calculations were performed after checking the data for poor image alignment, defocusing issues, and particles too thick to be analyzed. The potential for systematic error in the OVF calculation was also tested by assuming the incorrect composition. There is a small (about 0.5 %) OVF difference if the organic is erroneously assumed to be adipic acid rather than the known organic, sucrose. A much larger difference (up to 25 %) is seen if sodium chloride is assumed instead of ammonium sulfate. These results show that the OVF calculations are fairly insensitive to the organic while being much more sensitive to the choice of inorganic.

Sign in / Sign up

Export Citation Format

Share Document