scholarly journals A thermodynamic scaling law for electrically perturbed lipid membranes: validation with the steepest-entropy-ascent framework

2020 ◽  
Author(s):  
I. Goswami ◽  
R. Bielitz ◽  
S.S. Verbridge ◽  
M.R. von Spakovsky
Keyword(s):  
Electric Fields ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Scaling Law ◽  
Cancer Therapeutics ◽  
Successful Implementation ◽  
Outer Cell ◽  
Scaling Model ◽  
The Impact

AbstractExperimental evidence has demonstrated the potential of transient pulses of electric fields to alter mammalian cell phenotypes. Strategies with these pulsed electric fields (PEFs) have been developed for clinical applications in cancer therapeutics, in-vivo decellularization, and tissue regeneration. Successful implementation of these strategies involves understanding how PEFs impact the cellular structures and, hence, cell behavior. The caveat, however, is that the PEF parameter space comprised of different pulse widths, amplitudes, and the number of pulses is very large, and design of experiments to explore all possible combinations of PEF parameters is prohibitive from a cost and time standpoint. In this study, a scaling law based on the Ising model is introduced to understand the impact of PEFs on the outer cell lipid membrane so that an understanding developed in one PEF pulse regime may be extended to another. Experimental study is used to argue for the scaling model. Next, the validity of this scaling model to predict the behavior of both thermally quenched and electrically perturbed lipid membranes is demonstrated via computational predictions made by the steepest-entropy-ascent quantum thermodynamic (SEAQT) framework. Based on the simulation results, a form of scaled PEF parameters is thus proposed for lipid membrane.

scholarly journals Lipid Self-Assemblies under the Atomic Force Microscope

2021 ◽  
Vol 22 (18) ◽  
pp. 10085
Author(s):  
Aritz B. García-Arribas ◽  
Félix M. Goñi ◽  
Alicia Alonso
Keyword(s):  
Lipid Membranes ◽  
Lipid Membrane ◽  
Domain Size ◽  
Model Membranes ◽  
Model Systems ◽  
Systems Model ◽  
Atomic Force ◽  
Model Lipid Membranes ◽  
The Impact

Lipid model membranes are important tools in the study of biophysical processes such as lipid self-assembly and lipid–lipid interactions in cell membranes. The use of model systems to adequate and modulate complexity helps in the understanding of many events that occur in cellular membranes, that exhibit a wide variety of components, including lipids of different subfamilies (e.g., phospholipids, sphingolipids, sterols…), in addition to proteins and sugars. The capacity of lipids to segregate by themselves into different phases at the nanoscale (nanodomains) is an intriguing feature that is yet to be fully characterized in vivo due to the proposed transient nature of these domains in living systems. Model lipid membranes, instead, have the advantage of (usually) greater phase stability, together with the possibility of fully controlling the system lipid composition. Atomic force microscopy (AFM) is a powerful tool to detect the presence of meso- and nanodomains in a lipid membrane. It also allows the direct quantification of nanomechanical resistance in each phase present. In this review, we explore the main kinds of lipid assemblies used as model membranes and describe AFM experiments on model membranes. In addition, we discuss how these assemblies have extended our knowledge of membrane biophysics over the last two decades, particularly in issues related to the variability of different model membranes and the impact of supports/cytoskeleton on lipid behavior, such as segregated domain size or bilayer leaflet uncoupling.

scholarly journals Mimicking the Mammalian Plasma Membrane: An Overview of Lipid Membrane Models for Biophysical Studies

Biomimetics ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 3
Author(s):  
Alessandra Luchini ◽  
Giuseppe Vitiello
Keyword(s):  
Plasma Membrane ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Cell Membranes ◽  
Lipid Membrane ◽  
Lipid Phase ◽  
Chemical Information ◽  
Lipid Species ◽  
Membrane Models ◽  
The Impact

Cell membranes are very complex biological systems including a large variety of lipids and proteins. Therefore, they are difficult to extract and directly investigate with biophysical methods. For many decades, the characterization of simpler biomimetic lipid membranes, which contain only a few lipid species, provided important physico-chemical information on the most abundant lipid species in cell membranes. These studies described physical and chemical properties that are most likely similar to those of real cell membranes. Indeed, biomimetic lipid membranes can be easily prepared in the lab and are compatible with multiple biophysical techniques. Lipid phase transitions, the bilayer structure, the impact of cholesterol on the structure and dynamics of lipid bilayers, and the selective recognition of target lipids by proteins, peptides, and drugs are all examples of the detailed information about cell membranes obtained by the investigation of biomimetic lipid membranes. This review focuses specifically on the advances that were achieved during the last decade in the field of biomimetic lipid membranes mimicking the mammalian plasma membrane. In particular, we provide a description of the most common types of lipid membrane models used for biophysical characterization, i.e., lipid membranes in solution and on surfaces, as well as recent examples of their applications for the investigation of protein-lipid and drug-lipid interactions. Altogether, promising directions for future developments of biomimetic lipid membranes are the further implementation of natural lipid mixtures for the development of more biologically relevant lipid membranes, as well as the development of sample preparation protocols that enable the incorporation of membrane proteins in the biomimetic lipid membranes.

Extreme Elongation of Vesicles Under DC Electric Fields

2008 ◽  
Author(s):  
Mohamed M. Sadik ◽  
David I. Shreiber ◽  
Jerry W. Shan ◽  
Hao Lin
Keyword(s):  
Electrical Conductivity ◽  
Electric Fields ◽  
Lipid Membranes ◽  
Deformation Behavior ◽  
Lipid Membrane ◽  
Model System ◽  
Dominant Factor ◽  
Conductivity Ratio ◽  
Pathological Changes ◽  
Dc Electric Fields

Electrodeformation refers to the deformation of cell or vesicle lipid membranes under the application of an electric field. Such a phenomenon often accompanies electroporation processes, and also can be leveraged to detect pathological changes in cells. Recent studies have suggested that the electrical conductivity difference across the lipid membrane is a dominant factor in determining the characteristics of deformation, and various regimes of deformation were observed. Using a vesicle model system, the current work is the first report of extreme elongation of vesicles of high conductivity ratio under DC electric fields. The results suggest that the osmolarity difference between the encapsulated and bathing solutions may contribute to such abnormal deformation behavior.

Fluorocarbons and Fluorosurfactants for In Vivo Oxygen Transport (Blood Substitutes), Imaging, and Drug Delivery

MRS Bulletin ◽  
1999 ◽  
Vol 24 (5) ◽  
pp. 42-48 ◽  
Author(s):  
Jean G. Riess ◽  
Marie Pierre Krafft
Keyword(s):  
Drug Delivery ◽  
Lipid Membranes ◽  
Research Collaboration ◽  
The United States ◽  
Blood Substitutes ◽  
Oxygen Carriers ◽  
Colloidal Systems ◽  
Preclinical Development ◽  
The Impact

The development of biomaterials to treat, repair, or reconstruct the human body is an increasingly important component of materials research. Collaboration between materials researchers and their industrial and clinical partners is essential for the development of this complex field. To demonstrate the importance of these interactions, two articles in this issue focus on advances in biomaterials relating to the use of colloidal systems for transport, drug delivery, and other medical applications. These articles were coordinated by Dominique Muster (Université Louis Pasteur, Strasbourg) and Franz Burny (Hôpital Erasme, Brussels). The following is the first of these two articles.A large variety of colloidal Systems involving highly fluorinated components have been prepared and investigated in recent years. These fluorinated Systems comprise diverse ty pes of emulsions (e.g., direct, reverse, and multiple emulsions; microemulsions; gel emulsions; waterless emulsions) with a fluorocarbon phase (and often a fluorinated Surfactant), and a ränge of self-assemblies (vesicles, tubules, helices, ribbons, etc.) made from fluorinated amphiphiles. Fluorinated Langmuir films and fluorinated black lipid membranes (BLMs) also have been investigated.Research in this area was driven by the potential applications of such materials in medicine and biology. Fluorocarbon-based products are being developed as injectable oxygen carriers (“blood Substitutes”), media for liquid Ventilation, drug delivery Systems, and contrast agents for ultrasound imaging. One such agent has recently been approved for use in Europe and the United States. Several more products are in an advanced stage of clinical evaluation, and others are in various stages of preclinical development. From a more fundamental Standpoint, these materials are being investigated for assessing and understanding the impact that fluorinated components have on the formation, stability, structure, and properties of colloida l Systems in comparison with their hydrocarbon counterparts. The attention given to fluorinated colloids prompted the synthesis of numerous new families of fluorinated amphiphiles, which were to become components of such colloids.

Experimental Study of the Impact of Alisma plantago-aquatica Secretions on Pathogenic Bacteria

2014 ◽  
Vol 1 (3) ◽  
pp. 3-7
Author(s):  
O. Zhukorskyy ◽  
O. Hulay
Keyword(s):  
Pathogenic Bacteria ◽  
Initial Density ◽  
Biologically Active ◽  
Erysipelothrix Rhusiopathiae ◽  
Natural Focus ◽  
Test Species ◽  
Popula Tions ◽  
And Control ◽  
The Impact

Aim. To estimate the impact of in vivo secretions of water plantain (Alisma plantago-aquatica) on the popula- tions of pathogenic bacteria Erysipelothrix rhusiopathiae. Methods. The plants were isolated from their natural conditions, the roots were washed from the substrate residues and cultivated in laboratory conditions for 10 days to heal the damage. Then the water was changed; seven days later the selected samples were sterilized using fi lters with 0.2 μm pore diameter. The dilution of water plantain root diffusates in the experimental samples was 1:10–1:10,000. The initial density of E. rhusiopathiae bacteria populations was the same for both experimental and control samples. The estimation of the results was conducted 48 hours later. Results. When the dilution of root diffusates was 1:10, the density of erysipelothrixes in the experimental samples was 11.26 times higher than that of the control, on average, the dilution of 1:100 − 6.16 times higher, 1:1000 – 3.22 times higher, 1:10,000 – 1.81 times higher, respectively. Conclusions. The plants of A. plantago-aquatica species are capable of affecting the populations of E. rhusiopathiae pathogenic bacteria via the secretion of biologically active substances into the environment. The consequences of this interaction are positive for the abovementioned bacteria, which is demon- strated by the increase in the density of their populations in the experiment compared to the control. The intensity of the stimulating effect on the populations of E. rhusiopathiae in the root diffusates of A. plantago-aquatica is re- ciprocally dependent on the degree of their dilution. The investigated impact of water plantain on erysipelothrixes should be related to the topical type of biocenotic connections, the formation of which between the test species in the ecosystems might promote maintaining the potential of natural focus of rabies. Keywords: Alisma plantago-aquatica, in vivo secretions, Erysipelothrix rhusiopathiae, population density, topical type of connections.

Curcumin-containing Silver Nanoparticles prevent carbon tetrachlorideinduced hepatotoxicity in mice

2020 ◽  
Vol 23 ◽  
Author(s):  
Hossam Ebaid ◽  
Mohamed Habila ◽  
Iftekhar Hassan ◽  
Jameel Al-Tamimi ◽  
Mohamed S. Omar ◽  
...  
Keyword(s):  
Dna Damage ◽  
Silver Nanoparticles ◽  
Nuclear Dna ◽  
Liquid Paraffin ◽  
Tail Length ◽  
Hepatic Tissue ◽  
Tissue Destruction ◽  
Group 2 ◽  
The Impact

Background: Hepatotoxicity remains an important clinical challenge. Hepatotoxicity observed in response to toxins and hazardous chemicals may be alleviated by delivery of the curcumin in silver nanoparticles (AgNPs-curcumin). In this study, we examined the impact of AgNPs-curcumin in a mouse model of carbon tetrachloride (CCl4)-induced hepatic injury. Methods: Male C57BL/6 mice were divided into three groups (n=8 per group). Mice in group 1 were treated with vehicle control alone, while mice in Group 2 received a single intraperitoneal injection of 1 ml/kg CCl4 in liquid paraffin (1:1 v/v). Mice in group 3 were treated with 2.5 mg/kg AgNPs-curcumin twice per week for three weeks after the CCl4 challenge. Results: Administration of CCL4 resulted in oxidative dysregulation, including significant reductions in reduced glutathione and concomitant elevations in the level of malondialdehyde (MDA). CCL4 challenge also resulted in elevated levels of serum aspartate transaminase (AST) and alanine transaminase (ALT); these findings were associated with the destruction of hepatic tissues. Treatment with AgNPs-curcumin prevented oxidative imbalance, hepatic dysfunction, and tissue destruction. A comet assay revealed that CCl4 challenge resulted in significant DNA damage as documented by a 70% increase in nuclear DNA tail-length; treatment with AgNPs-curcumin inhibited the CCL4-mediated increase in nuclear DNA tail-length by 34%. Conclusion: Administration of AgNPs-curcumin resulted in significant antioxidant activity in vivo. This agent has the potential to prevent the hepatic tissue destruction and DNA damage that results from direct exposure to CCL4.

The impact of Zataria multiflora Boiss extract on in vitro and in vivo Th1/Th2 cytokine (IFN-γ/IL4) balance

2013 ◽  
Vol 150 (3) ◽  
pp. 1024-1031 ◽  
Author(s):  
Mohammad Hossein Boskabady ◽  
Sakine Shahmohammadi Mehrjardi ◽  
Abadorrahim Rezaee ◽  
Houshang Rafatpanah ◽  
Sediqeh Jalali
Keyword(s):  
Zataria Multiflora ◽  
Th2 Cytokine ◽  
Ifn Γ ◽  
The Impact

scholarly journals The impact of FGF19/FGFR4 signaling inhibition in antitumor activity of multi-kinase inhibitors in hepatocellular carcinoma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroaki Kanzaki ◽  
Tetsuhiro Chiba ◽  
Junjie Ao ◽  
Keisuke Koroki ◽  
Kengo Kanayama ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
Progression Free Survival ◽  
Erk Signaling ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antitumor Effects ◽  
The Impact

AbstractFGF19/FGFR4 autocrine signaling is one of the main targets for multi-kinase inhibitors (MKIs). However, the molecular mechanisms underlying FGF19/FGFR4 signaling in the antitumor effects to MKIs in hepatocellular carcinoma (HCC) remain unclear. In this study, the impact of FGFR4/ERK signaling inhibition on HCC following MKI treatment was analyzed in vitro and in vivo assays. Serum FGF19 in HCC patients treated using MKIs, such as sorafenib (n = 173) and lenvatinib (n = 40), was measured by enzyme-linked immunosorbent assay. Lenvatinib strongly inhibited the phosphorylation of FRS2 and ERK, the downstream signaling molecules of FGFR4, compared with sorafenib and regorafenib. Additional use of a selective FGFR4 inhibitor with sorafenib further suppressed FGFR4/ERK signaling and synergistically inhibited HCC cell growth in culture and xenograft subcutaneous tumors. Although serum FGF19high (n = 68) patients treated using sorafenib exhibited a significantly shorter progression-free survival and overall survival than FGF19low (n = 105) patients, there were no significant differences between FGF19high (n = 21) and FGF19low (n = 19) patients treated using lenvatinib. In conclusion, robust inhibition of FGF19/FGFR4 is of importance for the exertion of antitumor effects of MKIs. Serum FGF19 levels may function as a predictive marker for drug response and survival in HCC patients treated using sorafenib.

scholarly journals Electrochemical Properties of Lipid Membranes Self-Assembled from Bicelles

Membranes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Damian Dziubak ◽  
Kamil Strzelak ◽  
Slawomir Sek
Keyword(s):  
Electrochemical Properties ◽  
Self Assembly ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Membrane Resistance ◽  
Electrochemical Characteristics ◽  
Freeze Thaw ◽  
Lipid Films ◽  
Supported Lipid Membranes

Supported lipid membranes are widely used platforms which serve as simplified models of cell membranes. Among numerous methods used for preparation of planar lipid films, self-assembly of bicelles appears to be promising strategy. Therefore, in this paper we have examined the mechanism of formation and the electrochemical properties of lipid films deposited onto thioglucose-modified gold electrodes from bicellar mixtures. It was found that adsorption of the bicelles occurs by replacement of interfacial water and it leads to formation of a double bilayer structure on the electrode surface. The resulting lipid assembly contains numerous defects and pinholes which affect the permeability of the membrane for ions and water. Significant improvement in morphology and electrochemical characteristics is achieved upon freeze–thaw treatment of the deposited membrane. The lipid assembly is rearranged to single bilayer configuration with locally occurring patches of the second bilayer, and the number of pinholes is substantially decreased. Electrochemical characterization of the lipid membrane after freeze–thaw treatment demonstrated that its permeability for ions and water is significantly reduced, which was manifested by the relatively high value of the membrane resistance.

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