scholarly journals Hybrid Unilamellar Vesicles of Phospholipids and Block Copolymers with Crystalline Domains

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1232
Author(s):  
Yoo Kyung Go ◽  
Nurila Kambar ◽  
Cecilia Leal
Keyword(s):  
Phase Separation ◽  
Block Copolymers ◽  
Phase Behavior ◽  
Laser Scanning ◽  
Structural Phase ◽  
Dynamical Behavior ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Lamellar Phases ◽  
Poly Ethylene

Phospholipid (PL) membranes are ubiquitous in nature and their phase behavior has been extensively studied. Lipids assemble in a variety of structures and external stimuli can activate a quick switch between them. Amphiphilic block copolymers (BCPs) can self-organize in analogous structures but are mechanically more robust and transformations are considerably slower. The combination of PL dynamical behavior with BCP chemical richness could lead to new materials for applications in bioinspired separation membranes and drug delivery. It is timely to underpin the phase behavior of these hybrid systems and a few recent studies have revealed that PL–BCP membranes display synergistic structural, phase-separation, and dynamical properties not seen in pure components. One example is phase-separation in the membrane plane, which seems to be strongly affected by the ability of the PL to form lamellar phases with ordered alkyl chains. In this paper we focus on a rather less explored design handle which is the crystalline properties of the BCP component. Using a combination of confocal laser scanning microscopy and X-ray scattering we show that hybrid membranes of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and methoxy-poly(ethylene glycol)-b-poly(ε-caprolactone) (mPEG-b-PCL) display BCP-rich and PL-rich domains when the BCP comprises crystalline moieties. The packing of the hydrophilic part of the BCP (PEG) favors mixing of DPPC at the molecular level or into nanoscale domains while semi-crystalline and hydrophobic PCL moieties bolster microscopic domain formation in the hybrid membrane plane.

Interactions of WPI and Xanthan in Microstructure and Rheological Properties of Gels and Emulsions

2007 ◽  
Vol 3 (4) ◽  
Author(s):  
Kooshan Nayebzadeh ◽  
Jianshe Chen ◽  
SM Mohammad Mousavi
Keyword(s):  
Phase Separation ◽  
Whey Protein ◽  
Viscoelastic Properties ◽  
Xanthan Gum ◽  
Laser Scanning ◽  
Structural Changes ◽  
Spherical Shape ◽  
Laser Scanning Microscopy ◽  
Concentration Addition ◽  
Confocal Laser

The effect of addition of xanthan gum (0.05, 0.1, 0.15, 0.25% weight/volume) on the formation and rheology of whey protein isolate (WPI)-xanthan gum gels has been investigated at neutral pH. The elastic modulus (G') values of the gelling test were compared. Low concentration of xanthan added (<0.05%,w/v) has a synergistic effect on the gel strength depend on phase separation, so that whey proteins concentrated in their phase and finally mixed gels with xanthan would be stronger than WPI gels. At higher xanthan concentration (> 0.05%, w/v), antagonist effect was observed by reducing the connection between clusters of whey protein by xanthan, so aggregation disruption and a related decrease in (G'). The phase separation microstructure of WPI-stabilized emulsion containing xanthan gum added has been investigated by rheology and confocal laser scanning microscopy. Xanthan was stained with Fluorescein 5(6)-isothiocyanate (FITC). Low xanthan concentration addition lead to depletion flocculation and increasing the xanthan concentration cause to increase the viscoelasticity of aqueous phase, so retarded macroscopic phase separation over period investigated. Structural changes in emulsion were observed in viscoelastic properties of separated phase in the rheometer. The CLSM image shows different phase which have different viscoelastic properties; xanthan-rich region transforms into the spherical shape which has the lowest interfacial energy and gradually two separated ultimately.

scholarly journals The cyclodextrin inclusion complex-containing biodegradable polymeric systems as drug carrier

2019 ◽  
Vol 17 (6) ◽  
pp. 61
Author(s):  
Trâm Trương Lê Bích
Keyword(s):  
Block Copolymers ◽  
Self Assembly ◽  
Laser Scanning ◽  
Drug Carrier ◽  
Drug Carriers ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Hep G2 ◽  
Polymeric Systems ◽  
Vis Spectroscopy

This article shows that the supramolecular micelle assemblies from PCL-b-P4VP block copolymers with α-CD via self-assembly of inclusion complexes in an aqueous solution. Dox encapsulation and the release at different pH of supramolecular micelle assemblies from poly (ε-caprolactone-block-4-vinylpyridine) (PCL-b-P4VP) block copolymers with α-CD showed excellent cytocompatibility. Dox was successfully loaded into the micelles with a loading content of 14.4% and loading efficiency of 28.9% by using UV-Vis spectroscopy (UV). The Dox loaded micelles showed lower cytotoxicity than free drugs, and could efficiently deliver and release the drug into human hepatocellular carcinoma (Hep-G2) cells as confirmed by confocal laser scanning microscopy (CLSM). These properties make the polymer micelles attractive as drug carriers for pharmaceutical applications.

3-D imaging of cells using a confocal laser scanning microscope and digital image processing

1988 ◽  
Vol 46 ◽  
pp. 96-97
Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Biochemical Processes ◽  
Adjacent Structures

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

Vacuoles Induced in Mammalian Cells by Helicobacter Cytotoxin are Acidic Organelles

1990 ◽  
Vol 48 (3) ◽  
pp. 168-169
Author(s):  
M. H. Chestnut ◽  
C. E. Catrenich
Keyword(s):  
Acridine Orange ◽  
Mammalian Cells ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ulcer Disease ◽  
Gastroduodenal Disease ◽  
H Pylori

Helicobacter pylori is a non-invasive, Gram-negative spiral bacterium first identified in 1983, and subsequently implicated in the pathogenesis of gastroduodenal disease including gastritis and peptic ulcer disease. Cytotoxic activity, manifested by intracytoplasmic vacuolation of mammalian cells in vitro, was identified in 55% of H. pylori strains examined. The vacuoles increase in number and size during extended incubation, resulting in vacuolar and cellular degeneration after 24 h to 48 h. Vacuolation of gastric epithelial cells is also observed in vivo during infection by H. pylori. A high molecular weight, heat labile protein is believed to be responsible for vacuolation and to significantly contribute to the development of gastroduodenal disease in humans. The mechanism by which the cytotoxin exerts its effect is unknown, as is the intracellular origin of the vacuolar membrane and contents. Acridine orange is a membrane-permeant weak base that initially accumulates in low-pH compartments. We have used acridine orange accumulation in conjunction with confocal laser scanning microscopy of toxin-treated cells to begin probing the nature and origin of these vacuoles.

Use of confocal laser scanning microscopy and a computer model to understand ink cavitation and filamentation

TAPPI Journal ◽  
2010 ◽  
Vol 9 (10) ◽  
pp. 7-15
Author(s):  
HANNA KOIVULA ◽  
DOUGLAS BOUSFIELD ◽  
MARTTI TOIVAKKA
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Print Quality ◽  
Length Scale ◽  
Offset Printing ◽  
Significant Difference ◽  
Printing Speed

In the offset printing process, ink film splitting has an important impact on formation of ink filaments. The filament size and its distribution influence the leveling of ink and hence affect ink setting and the print quality. However, ink filaments are difficult to image due to their short lifetime and fine length scale. Due to this difficulty, limited work has been reported on the parameters that influence filament size and methods to characterize it. We imaged ink filament remains and quantified some of their characteristics by changing printing speed, ink amount, and fountain solution type. Printed samples were prepared using a laboratory printability tester with varying ink levels and operating settings. Rhodamine B dye was incorporated into fountain solutions to aid in the detection of the filaments. The prints were then imaged with a confocal laser scanning microscope (CLSM) and images were further analyzed for their surface topography. Modeling of the pressure pulses in the printing nip was included to better understand the mechanism of filament formation and the origin of filament length scale. Printing speed and ink amount changed the size distribution of the observed filament remains. There was no significant difference between fountain solutions with or without isopropyl alcohol on the observed patterns of the filament remains.

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