scholarly journals Self-assembly, Stability and the Electrical Characteristics of Cell Membranes

1999 ◽  
Vol 52 (1) ◽  
pp. 117 ◽  
Author(s):  
Hans G. L. Coster
Keyword(s):  
Electrical Properties ◽  
Self Assembly ◽  
Cell Membranes ◽  
Mechanical Analysis ◽  
Fundamental Research ◽  
Statistical Mechanical ◽  
Commercially Important ◽  
The Stability ◽  
And Function ◽  
Molecular Organisation

Living cells are enveloped in an ultra thin ( ~ 6 nm) membrane which consists basically of a bi-molecular film of lipid molecules in which are embedded functional proteins that perform a variety of functions, including energy transduction, signalling, transport of ions (and other molecules) etc., and also acts as a diffusion barrier between the cell interior (cytoplasm) and the external medium. A simple statistical mechanical analysis of the self-assembly of the membrane from its components provides useful insights into the molecular organisation of the membrane and its electrical properties. The stability of the structure is also closely connected to its electrical properties and this has provided not only a useful tool for fundamental research but has spawned also applications, some of which have had a major impact in biomedical research and are now being exploited commercially. An overview is given of the rapid progress made in our understanding of the physics of both the molecular organisation and function of cell membranes and some of the fascinating and socially and commercially important applications that have flowed from this.

Self-assembly and function of primitive cell membranes

2009 ◽  
Vol 160 (7) ◽  
pp. 449-456 ◽  
Author(s):  
Andrew Pohorille ◽  
David Deamer
Keyword(s):  
Self Assembly ◽  
Cell Membranes ◽  
Primitive Cell ◽  
And Function

scholarly journals Graphene Oxide-Chitosan Aerogels: Synthesis, Characterization, and Use as Adsorbent Material for Water Contaminants

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 149
Author(s):  
Filippo Pinelli ◽  
Tommaso Nespoli ◽  
Filippo Rossi
Keyword(s):  
Graphene Oxide ◽  
Self Assembly ◽  
Three Dimensional ◽  
Soft Materials ◽  
Complete Removal ◽  
Mechanical Analysis ◽  
Anionic Dyes ◽  
Water Contaminants ◽  
High Sorption ◽  
The Stability

Porous aerogels, formed by subjecting precursor hydrogels using a freeze-drying process, are certainly one of the most studied and synthetized soft materials, thanks to their important features such as elasticity, swelling behavior, softness, and micro and nanosized pores, which guarantee their applicability in various fields. Typically, these systems are synthetized working with natural or synthetic polymers, but in the last years great interest has been given to proper formulated aerogels able to combine polymeric structures with other moieties such as graphene or graphene oxide. This working strategy can be pivotal in many cases to tune important properties of the final system such as toughness, porosity, elasticity, electrical conductivity, or responsive behavior. In this work we propose the synthesis of chitosan graphene oxide aerogels obtained through self-assembly of graphene oxide sheets and chitosan chains. These three-dimensional systems were chemically characterized with IR and XRD technique and their inner structure was investigated through the scanning electron microscopy (SEM). Moreover, we mechanically characterized the material through dynamic mechanical analysis, showing the stability of these systems. Finally, the adsorption ability of these soft materials has been demonstrated using model molecules to simulate water contaminants showing the efficacy of those graphene-based systems even for the removal of anionic dyes. Complete removal of contaminants was obtained at low concentration of dyes in solution (100 mg/L), while with a higher amount of pollutant in the solution (350 mg/L) high sorption capacity (q > 200 mg/g) was observed.

scholarly journals Self-assembly of spectrin oligomers in vitro: a basis for a dynamic cytoskeleton.

1981 ◽  
Vol 88 (2) ◽  
pp. 463-468 ◽  
Author(s):  
J S Morrow ◽  
V T Marchesi
Keyword(s):  
Self Assembly ◽  
Erythrocyte Membranes ◽  
Membrane Structure And Function ◽  
High Concentrations ◽  
The Stability ◽  
And Function ◽  
Low Ionic Strength ◽  
Affinity Interaction

Purified human erythrocyte spectrin is able to form large oligomeric species without the collaboration of any other proteins. This reversible self-assembly process is both temperature and concentration dependent and seems to be mediated by the same kinds of low affinity noncovalent associations between spectrin monomers that promote tetramer formation. Low ionic strength extracts of erythrocyte membranes also contain these oligomeric species. These results support the idea that spectrin oligomers and the factors that regulate their formation may be responsible for both the stability and the versatility of the erythrocyte membrane cytoskeleton. It is postulated that the high concentrations of spectrin necessary for oligomerization are maintained in vivo by a high-affinity interaction with ankyrin. Such a coupling of high and low affinity interactions in multifunctional proteins may have significant implications for membrane structure and function.

Self-assembly, stability and conductance of amphotericin B channels: bridging the gap between structure and function

Nanoscale ◽  
2021 ◽  
Author(s):  
Joanna Zielińska ◽  
Milosz Wieczor ◽  
Paweł Chodnicki ◽  
Ewa Grela ◽  
Rafal Luchowski ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Self Assembly ◽  
Cell Membranes ◽  
Structure And Function ◽  
Fungal Cell ◽  
And Function ◽  
Toxic Drugs

Amphotericin B (AmB), one of the most powerful but also toxic drugs used to treat systemic mycoses, is believed to selectively permeabilize fungal cell membranes to ions in a sterol-dependent...

Preparation and Characterization of β-glucosidase Films for Stabilization and Handling in Dry Configurations

2020 ◽  
Vol 21 (8) ◽  
pp. 741-747
Author(s):  
Liguang Zhang ◽  
Yanan Shen ◽  
Wenjing Lu ◽  
Lengqiu Guo ◽  
Min Xiang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Protein Function ◽  
Protein Stabilization ◽  
Functional Protein ◽  
Elongation At Break ◽  
Gelatin Films ◽  
The Stability ◽  
And Function ◽  
General Method

Background: Although the stability of proteins is of significance to maintain protein function for therapeutical applications, this remains a challenge. Herein, a general method of preserving protein stability and function was developed using gelatin films. Method: Enzymes immobilized onto films composed of gelatin and Ethylene Glycol (EG) were developed to study their ability to stabilize proteins. As a model functional protein, β-glucosidase was selected. The tensile properties, microstructure, and crystallization behavior of the gelatin films were assessed. Result: Our results indicated that film configurations can preserve the activity of β-glucosidase under rigorous conditions (75% relative humidity and 37°C for 47 days). In both control films and films containing 1.8 % β-glucosidase, tensile strength increased with increased EG content, whilst the elongation at break increased initially, then decreased over time. The presence of β-glucosidase had a negligible influence on tensile strength and elongation at break. Scanning electron-microscopy (SEM) revealed that with increasing EG content or decreasing enzyme concentrations, a denser microstructure was observed. Conclusion: In conclusion, the dry film is a promising candidate to maintain protein stabilization and handling. The configuration is convenient and cheap, and thus applicable to protein storage and transportation processes in the future.

scholarly journals Interfacial Crystallization and Supramolecular Self-Assembly of Spider Silk Inspired Protein at the Water-Air Interface

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4239
Author(s):  
Pezhman Mohammadi ◽  
Fabian Zemke ◽  
Wolfgang Wagermaier ◽  
Markus B. Linder
Keyword(s):  
Self Assembly ◽  
Spider Silk ◽  
Assembly Process ◽  
Protein Solution ◽  
Time Resolved ◽  
Macromolecular Assembly ◽  
X Ray Scattering ◽  
Air Interface ◽  
Fundamental Research ◽  
Β Sheet

Macromolecular assembly into complex morphologies and architectural shapes is an area of fundamental research and technological innovation. In this work, we investigate the self-assembly process of recombinantly produced protein inspired by spider silk (spidroin). To elucidate the first steps of the assembly process, we examined highly concentrated and viscous pendant droplets of this protein in air. We show how the protein self-assembles and crystallizes at the water–air interface into a relatively thick and highly elastic skin. Using time-resolved in situ synchrotron X-ray scattering measurements during the drying process, we showed that the skin evolved to contain a high β-sheet amount over time. We also found that β-sheet formation strongly depended on protein concentration and relative humidity. These had a strong influence not only on the amount, but also on the ordering of these structures during the β-sheet formation process. We also showed how the skin around pendant droplets can serve as a reservoir for attaining liquid–liquid phase separation and coacervation from the dilute protein solution. Essentially, this study shows a new assembly route which could be optimized for the synthesis of new materials from a dilute protein solution and determine the properties of the final products.

scholarly journals Dispersion of Carbon Nanotubes with “Green” Detergents

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2908
Author(s):  
Kazuo Umemura ◽  
Ryo Hamano ◽  
Hiroaki Komatsu ◽  
Takashi Ikuno ◽  
Eko Siswoyo
Keyword(s):  
Carbon Nanotubes ◽  
Sodium Dodecyl ◽  
Detergent Solution ◽  
Absorbance Spectroscopy ◽  
Fundamental Research ◽  
The Stability ◽  
Single Walled Cnts ◽  
Better Than ◽  
Walled Cnts ◽  
Cnt Suspensions

Solubilization of carbon nanotubes (CNTs) is a fundamental technique for the use of CNTs and their conjugates as nanodevices and nanobiodevices. In this work, we demonstrate the preparation of CNT suspensions with “green” detergents made from coconuts and bamboo as fundamental research in CNT nanotechnology. Single-walled CNTs (SWNTs) with a few carboxylic acid groups (3–5%) and pristine multi-walled CNTs (MWNTs) were mixed in each detergent solution and sonicated with a bath-type sonicator. The prepared suspensions were characterized using absorbance spectroscopy, scanning electron microscopy, and Raman spectroscopy. Among the eight combinations of CNTs and detergents (two types of CNTs and four detergents, including sodium dodecyl sulfate (SDS) as the standard), SWNTs/MWNTs were well dispersed in all combinations except the combination of the MWNTs and the bamboo detergent. The stability of the suspensions prepared with coconut detergents was better than that prepared with SDS. Because the efficiency of the bamboo detergents against the MWNTs differed significantly from that against the SWNTs, the natural detergent might be useful for separating CNTs. Our results revealed that the use of the “green” detergents had the advantage of dispersing CNTs as well as SDS.

scholarly journals The traditional experience strategy (TES) and combined ultrasonography examination (CUE) for the treatment of lateral compression type 1 pelvic fractures: a historical control study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hai Huang ◽  
Bin-Fei Zhang ◽  
Ping Liu ◽  
Hong-Li Deng ◽  
Peng-Fei Wang ◽  
...  
Keyword(s):  
Pelvic Fractures ◽  
Definitive Treatment ◽  
Lateral Compression ◽  
Level Of Evidence ◽  
Conservative Group ◽  
Medical Records System ◽  
The Stability ◽  
And Function ◽  
Compression Type

Abstract Background It is difficult to judge the stability of lateral compression type-1 (LC-1) pelvic fracture, as it is often based on static images of the pelvis. Compared with the traditional experience strategy, ultrasonography examination may be able to distinguish operative and conservative patients before definitive treatment. However, in previous studies, we have not compared the outcomes between traditional experience strategy (TES group) and combined ultrasonography examination (CUE group). Thus, the aim of the study is comparing the differences between TES and CUE strategy, to identify the value of ultrasonography examination. Methods Medical records system for patients with LC-1 pelvic fractures who were treated with TES and CUE strategy were included. Patients’ baseline characteristics, treatment strategy, and function were recorded at follow-up. Functional outcomes were evaluated using the Majeed grading system. Results In total, 77 patients with LC-1 pelvic fractures were included in the study. There were 42 and 35 patients in TES and CUE group, respectively. Compared to TES group (69 %), there were less proportion patients chosen the operative treatment in CUE group (43 %, P = 0.021). The volume of intraoperative blood loss in CUE operative group was more than TES operative group (P = 0.037). There were more patients with complete sacral fracture in CUE operative group than TES operative group (P = 0.002). The Majeed scores in CUE conservative group was higher than TES conservative group (P = 0.008). The overall Majeed scores in CUE group was higher than that in TES group (P = 0.039). Conclusions The ultrasonography examination could relatively accurately identify the unstable LC-1 pelvis than the traditional experience strategy, the operative rate could be reduced and the overall function of LC-1 patients could be improved under the ultrasonography examination. Level of evidence Level III.

scholarly journals Characteristics and Clinical Application of Extracellular Vesicle-Derived DNA

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3827
Author(s):  
Jae Young Hur ◽  
Kye Young Lee
Keyword(s):  
Therapeutic Potential ◽  
Extracellular Vesicle ◽  
Clinical Settings ◽  
Biomarker Detection ◽  
Diagnosis And Prognosis ◽  
Double Stranded Dna ◽  
Fundamental Research ◽  
The Stability ◽  
Next Generation Sequencing Ngs ◽  
Generation Sequencing

Extracellular vesicles (EVs) carry RNA, proteins, lipids, and diverse biomolecules for intercellular communication. Recent studies have reported that EVs contain double-stranded DNA (dsDNA) and oncogenic mutant DNA. The advantage of EV-derived DNA (EV DNA) over cell-free DNA (cfDNA) is the stability achieved through the encapsulation in the lipid bilayer of EVs, which protects EV DNA from degradation by external factors. The existence of DNA and its stability make EVs a useful source of biomarkers. However, fundamental research on EV DNA remains limited, and many aspects of EV DNA are poorly understood. This review examines the known characteristics of EV DNA, biogenesis of DNA-containing EVs, methylation, and next-generation sequencing (NGS) analysis using EV DNA for biomarker detection. On the basis of this knowledge, this review explores how EV DNA can be incorporated into diagnosis and prognosis in clinical settings, as well as gene transfer of EV DNA and its therapeutic potential.

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