Search for: phospholipid
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    Fluorescent quantification of size and lamellarity of membrane nanotubes

    , Article European Biophysics Journal ; Vol. 43, Issue. 12 , 2014 , pp. 595-602 ; ISSN: 1432-1017 Baroji,Y. F ; Oddershede, L. B ; Reihani, S. N. S ; Bendix, P. M ; Sharif University of Technology
    Membrane nanotubes, ubiquitous in cellular systems, adopt a spectrum of curvatures and shapes that are dictated by their intrinsic physical characteristics as well as their interactions with the local cellular environment. A high bending flexibility is needed in the crowded cytoplasm where tubes often need to bend significantly in the axial direction at sub-micron length scales. We find the stiffness of spontaneously formed membrane nanotubes by measuring the persistence length of reconstituted membrane nanotubes freely suspended in solution and imaged by fluorescence microscopy. By quantifying the tube diameter we demonstrate for the first time that the persistence length scales linearly... 

    Hydration strongly affects the molecular and electronic structure of membrane phospholipids

    , Article Journal of Chemical Physics ; Volume 136, Issue 11 , 2012 ; 00219606 (ISSN) Mashaghi, A ; Partovi Azar, P ; Jadidi, T ; Nafari, N ; Maass, P ; Tabar, M. R. R ; Bonn, M ; Bakker, H. J ; Sharif University of Technology
    We investigate the structure and electronic properties of phosphatidylcholine (PC) under different degrees of hydration at the single-molecule and monolayer type level by linear scaling ab initio calculations. Upon hydration, the phospholipid undergoes drastic long-range conformational rearrangements which lead to a sickle-like ground-state shape. The structural unit of the tilted gel-phase PC appears to be a water-bridged PC dimer. We find that hydration dramatically alters the surface potential, dipole and quadrupole moments of the lipids and consequently guides the interactions of the lipids with other molecules and the communication between cells  

    Vesicle deformations by clusters of transmembrane proteins

    , Article Journal of Chemical Physics ; Volume 134, Issue 8 , 2011 ; 00219606 (ISSN) Bahrami, A. H ; Jalali, M. A ; Sharif University of Technology
    We carry out a coarse-grained molecular dynamics simulation of phospholipid vesicles with transmembrane proteins. We measure the mean and Gaussian curvatures of our protein-embedded vesicles and quantitatively show how protein clusters change the shapes of their host vesicles. The effects of depletion force and vesiculation on protein clustering are also investigated. By increasing the protein concentration, clusters are fragmented to smaller bundles, which are then redistributed to form more symmetric structures corresponding to lower bending energies. Big clusters and highly aspherical vesicles cannot be formed when the fraction of protein to lipid molecules is large  

    The Motility of Lipid Vesicles Due to Phase Transition in Transmemerance Proteine

    , M.Sc. Thesis Sharif University of Technology Heidari, Maziar (Author) ; Jalali, Mir Abbas (Supervisor)
    Phospholipid vesicles are able to carry drugs or DNA to infected or cancerous cells. The blood flow can carry them to their target positions but their performance will be enhanced if they complete their attack by swimming in final stages of their journey. Vesicles built only by lipid molecules have rotational symmetry and undergo a random motion in their solvents without having a preferred direction. In this project, we break the symmetrical shape of phospholipid vesicles by a cluster of transmembrane proteins. We use a triangulated model of the membrane, apply the method of multi-particle collision dynamics to the motion of solvent particles, and simulate the motility of vesicles for... 

    Enhanced autoionization of water at phospholipid interfaces

    , Article Journal of Physical Chemistry C ; Volume 117, Issue 1 , 2013 , Pages 510-514 ; 19327447 (ISSN) Mashaghi, A ; Partovi Azar, P ; Jadidi, T ; Anvari, M ; Jand, S. P ; Nafari, N ; Tabar, M. R. R ; Maass, P ; Bakker, H. J ; Bonn, M ; Sharif University of Technology
    The structure and autoionization of water at the water-phospholipid interface are investigated by ab initio molecular dynamics and ab initio Monte Carlo simulations using local density approximation (LDA) and generalized gradient approximation (GGA) for the exchange-correlation energy functional. Depending on the lipid headgroup, strongly enhanced ionization is observed, leading to the dissociation of several water molecules into H+ and OH- per lipid. The results can shed light on the phenomena of the high proton conductivity along membranes that has been reported experimentally  

    A molecular dynamics simulation study of nanomechanical properties of asymmetric lipid bilayer

    , Article Journal of Membrane Biology ; Volume 246, Issue 1 , 2013 , Pages 67-73 ; 00222631 (ISSN) Maftouni, N ; Amininasab, M ; Vali, M ; Ejtehadi, M ; Kowsari, F ; Sharif University of Technology
    A very important part of the living cells of biological systems is the lipid membrane. The mechanical properties of this membrane play an important role in biophysical studies. Investigation as to how the insertion of additional phospholipids in one leaflet of a bilayer affects the physical properties of the obtained asymmetric lipid membrane is of recent practical interest. In this work a coarse-grained molecular dynamics simulation was carried out in order to compute the pressure tensor, the lateral pressure, the surface tension and the first moment of lateral pressure in each leaflet of such a bilayer. Our simulations indicate that adding more phospholipids into one monolayer results in... 

    Analytical methods in fatty acid analysis for microbial applications: the recent trends

    , Article Preparative Biochemistry and Biotechnology ; Volume 51, Issue 10 , 2021 , Pages 937-952 ; 10826068 (ISSN) Homayoonfar, M ; Roosta Azad, R ; Sardari, S ; Sharif University of Technology
    Taylor and Francis Ltd  2021
    Fatty acids are among the most important components of many biological systems and have been highlighted in many research fields in recent decades. In the food industry, it is important to check the amount and types of fatty acids in edible oils, beverages and other foods products, and checking the fatty acids parameters are among the quality control parameters for those products. In medical applications, investigation of fatty acids in biological samples and comparing imbalances in them can help to diagnose some diseases. On the other hand, the development of cell factories for the production of biofuels and other valuable chemicals requires the accurate analysis of fatty acids, which serve... 

    Smart liposomal drug delivery for treatment of oxidative stress model in human embryonic stem cell-derived retinal pigment epithelial cells

    , Article International Journal of Pharmaceutics ; Volume 548, Issue 1 , 2018 , Pages 62-72 ; 03785173 (ISSN) Behroozi, F ; Abdkhodaie, M. J ; Sadeghi Abandansari, H ; Satarian, L ; Kazemi Ashtiani, M ; Jaafari, M. R ; Baharvand, H ; Sharif University of Technology
    Oxidative stress has been implicated in the progression of age-related macular degeneration (AMD). Treatment with antioxidants seems to delay progression of AMD. In this study, we suggested an antioxidant delivery system based on redox-sensitive liposome composed of phospholipids and a diselenide centered alkyl chain. Dynamic light scattering assessment indicated that the liposomes had an average size of 140 nm with a polydispersity index below 0.2. The percentage of encapsulation efficiency of the liposomes was calculated by high-performance liquid chromatography. The carriers were loaded with N-acetyl cysteine as a model antioxidant drug. We demonstrated responsiveness of the nanocarrier... 

    Effect of electrolyte concentration on microstructure and properties of micro arc oxidized hydroxyapatite/titania nanostructured composite

    , Article Materials Science and Engineering C ; Volume 33, Issue 5 , 2013 , Pages 2555-2561 ; 09284931 (ISSN) Abbasi, S ; Golestani Fard, F ; Mirhosseini, S. M. M ; Ziaee, A ; Mehrjoo, M ; Sharif University of Technology
    Micro arc oxidation was employed to grow TiO2/hydroxyapatite composite layer on titanium substrate. The correlation between electrolyte concentration, diameter and density of the pores in fabricated layers was investigated. Therefore, the effect of electrolyte concentration on composition and morphology of grown layers was studied using SEM, EDX, XRD and XPS techniques. Samples were coated in electrolytes containing 5, 10 and 15 g/l calcium acetate and 1, 3 and 5 g/l β-glycerophosphate, at optimized voltage for 3 min. Pore size variations obey a similar pattern by the addition of both calcium acetate and β-glycerophosphatein various concentrations based on SEM observations. However,... 

    MAO-derived hydroxyapatite-TiO 2 nanostructured bio-ceramic films on titanium

    , Article Materials Research Bulletin ; Volume 47, Issue 11 , 2012 , Pages 3407-3412 ; 00255408 (ISSN) Abbasi, S ; Golestani Fard, F ; Rezaie, H. R ; Mirhosseini, S. M. M ; Ziaee, A ; Sharif University of Technology
    Micro Arc Oxidation (MAO) process was utilized to fabricate nano bioceramic TiO 2-hydroxyapatite coatings on titanium substrates. Samples were produced in electrolytes contained 1 g/l β-glycerophosphate and 5, 10 and 15 g/l calcium acetate for 3, 6 and 10 min at 350 V. The techniques including XRD, XPS, SEM, FESEM and EDX were employed to study the effect of processing parameters. Hydroxyapatite, anatase, α-tri calcium phosphate and calcium titanate phases as well as 30-60 nm-size crystals were detected in the coating layer. It was also observed that the pore volume would increase by increasing the electrolyte concentration. The growth time was also found to influence the total pore volume.... 

    Emerging phospholipid nanobiomaterials for biomedical applications to lab-on-a-chip, drug delivery, and cellular engineering

    , Article ACS Applied Bio Materials ; 2021 ; 25766422 (ISSN) Rahimnejad, M ; Rabiee, N ; Ahmadi, S ; Jahangiri, S ; Sajadi, S. M ; Akhavan, O ; Saeb, M. R ; Kwon, W ; Kim, M ; Hahn, S. K ; Sharif University of Technology
    American Chemical Society  2021
    The design of advanced nanobiomaterials to improve analytical accuracy and therapeutic efficacy has become an important prerequisite for the development of innovative nanomedicines. Recently, phospholipid nanobiomaterials including 2-methacryloyloxyethyl phosphorylcholine (MPC) have attracted great attention with remarkable characteristics such as resistance to nonspecific protein adsorption and cell adhesion for various biomedical applications. Despite many recent reports, there is a lack of comprehensive review on the phospholipid nanobiomaterials from synthesis to diagnostic and therapeutic applications. Here, we review the synthesis and characterization of phospholipid nanobiomaterials... 

    A metabonomics study on crohn's disease using nuclear magnetic resonance spectroscopy

    , Article HealthMED ; Volume 6, Issue 11 , July , 2012 , Pages 3577-3583 ; 18402291 (ISSN) Fathi, F ; Kyani, A ; Nejad, M. R ; Rezaye Tavirani, M ; Naderi, N ; Zali, M. R ; Tafazzoli, M ; Oskouie, A. A ; Sharif University of Technology
    Objective: Crohn's disease (CD) is one the important illnesses can affect any part of the gastrointestinal tract. CD is not easily diagnosed using the clinical tests. Thus, the discovery of proper methods would be a major step towards CD diagnosis. The aim of this study was to seek the metabolic biomarkers causes of CD compare to control group. Materials and Methods: In present study, we employed metabolic profiling using proton nuclear magnetic resonance spectroscopy (1HNMR) to find metabolites in serum which are helpful for the diagnosis of CD. Classification of CD and healthy subject was done using classification and regression trees (CART). The metabolites that caused changes in people... 

    A pilot study of the effect of phospholipid curcumin on serum metabolomic profile in patients with non-alcoholic fatty liver disease: a randomized, double-blind, placebo-controlled trial

    , Article European Journal of Clinical Nutrition ; Volume 73, Issue 9 , 2019 , Pages 1224-1235 ; 09543007 (ISSN) Chashmniam, S ; Mirhafez, S. R ; Dehabeh, M ; Hariri, M ; Azimi Nezhad, M ; Nobakht M. Gh, B. F ; Sharif University of Technology
    Nature Publishing Group  2019
    Background/Objectives: Curcumin, a natural polyphenol compound in the spice turmeric, has been found to have potent anti-oxidative and anti-inflammatory activity. Curcumin may treat non-alcoholic fatty liver disease (NAFLD) through its beneficial effects on biomarkers of oxidative stress (OS) and inflammation, which are considered as two feature of this disease. However, the effects of curcumin on NAFLD have been remained poorly understood. This investigation evaluated the effects of administrating curcumin on metabolic status in NAFLD patients. Subjects/Methods: Fifty-eight NAFLD patients participated in a randomized, double-blind, placebo-controlled parallel design of study. The subjects... 

    Recent advances in the design and applications of amyloid-β peptide aggregation inhibitors for Alzheimer’s disease therapy

    , Article Biophysical Reviews ; Volume 11, Issue 6 , 2019 , Pages 901-925 ; 18672450 (ISSN) Jokar, S ; Khazaei, S ; Behnammanesh, H ; Shamloo, A ; Erfani, M ; Beiki, D ; Bavi, O ; Sharif University of Technology
    Springer  2019
    Alzheimer’s disease (AD) is an irreversible neurological disorder that progresses gradually and can cause severe cognitive and behavioral impairments. This disease is currently considered a social and economic incurable issue due to its complicated and multifactorial characteristics. Despite decades of extensive research, we still lack definitive AD diagnostic and effective therapeutic tools. Consequently, one of the most challenging subjects in modern medicine is the need for the development of new strategies for the treatment of AD. A large body of evidence indicates that amyloid-β (Aβ) peptide fibrillation plays a key role in the onset and progression of AD. Recent studies have reported... 

    Injectable in situ forming kartogenin-loaded chitosan hydrogel with tunable rheological properties for cartilage tissue engineering

    , Article Colloids and Surfaces B: Biointerfaces ; Volume 192 , 2020 Dehghan-Baniani, D ; Chen, Y ; Wang, D ; Bagheri, R ; Solouk, A ; Wu, H ; Sharif University of Technology
    Elsevier B.V  2020
    Limited regeneration capacity of cartilage can be addressed by tissue engineering approaches including localized delivery of bioactive agents using biomaterials. Although chitosan hydrogels have been considered as appropriate candidates for these purposes, however, their poor mechanical properties limit their real applications. Here, we develop in situ forming chitosan hydrogels with enhanced shear modulus by chemical modification of chitosan using N-(β-maleimidopropyloxy) succinimide ester (BMPS). Moreover, we utilize β-Glycerophosphate (β-GP) in the hydrogels for achieving thermosensitivity. We investigate the effects of BMPS, β-GP and chitosan concentration on rheological and swelling...