scholarly journals Modulation of Schlemm's canal endothelial cell stiffness via latrunculin loaded block copolymer micelles

2018 ◽  
Vol 106 (7) ◽  
pp. 1771-1779 ◽  
Author(s):  
Trevor Stack ◽  
Amir Vahabikashi ◽  
Mark Johnson ◽  
Evan Scott
Keyword(s):  
Endothelial Cell ◽  
Block Copolymer ◽  
Cell Stiffness ◽  
Schlemm’S Canal ◽  
Schlemm's Canal ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

scholarly journals Mechanical responsiveness of the endothelial cell of Schlemm's canal: scope, variability and its potential role in controlling aqueous humour outflow

2011 ◽  
Vol 9 (71) ◽  
pp. 1144-1155 ◽  
Author(s):  
E. H. Zhou ◽  
R. Krishnan ◽  
W. D. Stamer ◽  
K. M. Perkumas ◽  
K. Rajendran ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Endothelial Cell ◽  
Aqueous Humour ◽  
Open Angle Glaucoma ◽  
Primary Cultures ◽  
Cell Stiffness ◽  
Donor Strain ◽  
Outflow Resistance ◽  
Schlemm’S Canal ◽  
Schlemm's Canal

Primary open-angle glaucoma is associated with elevated intraocular pressure, which in turn is believed to result from impaired outflow of aqueous humour. Aqueous humour outflow passes mainly through the trabecular meshwork (TM) and then through pores formed in the endothelium of Schlemm's canal (SC), which experiences a basal-to-apical pressure gradient. This gradient dramatically deforms the SC endothelial cell and potentially contributes to the formation of those pores. However, mechanical properties of the SC cell are poorly defined. Using optical magnetic twisting cytometry and traction force microscopy, here we characterize the mechanical properties of primary cultures of the human SC cell, and for the first time, the scope of their changes in response to pharmacological agents that are known to modulate outflow resistance. Lysophosphatidic acid, sphingosine-1-phosphate (S1P) and thrombin caused an increase in cell stiffness by up to 200 per cent, whereas in most cell strains, exposure to latrunculin A, isoproterenol, dibutryl cyclic-AMP or Y-27632 caused a decrease in cell stiffness by up to 80 per cent, highlighting that SC cells possess a remarkably wide contractile scope. Drug responses were variable across donors. S1P, for example, caused 200 per cent stiffening in one donor strain but only 20 per cent stiffening in another. Isoproterenol caused dose-dependent softening in three donor strains but little or no response in two others, a finding mirrored by changes in traction forces and consistent with the level of expression of β 2 -adrenergic receptors. Despite donor variability, those drugs that typically increase outflow resistance systematically caused cell stiffness to increase, while in most cases, those drugs that typically decrease outflow resistance caused cell stiffness to decrease. These findings establish the endothelial cell of SC as a reactive but variable mechanical component of the aqueous humour outflow pathway. Although the mechanism and locus of increased outflow resistance remain unclear, these data suggest the SC endothelial cell to be a modulator of outflow resistance.

β-lactam Functionalized Poly(isoprene-b-ethylene oxide) Amphiphilic Block Copolymer Micelles as a New Nanocarrier System for Curcumin

2010 ◽  
Vol 6 (3) ◽  
pp. 277-284 ◽  
Author(s):  
Konstantinos Gardikis ◽  
Konstantinos Dimas ◽  
Aristidis Georgopoulos ◽  
Eleni Kaditi ◽  
Stergios Pispas ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Ethylene Oxide ◽  
Amphiphilic Block Copolymer ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

Donnan Equilibria in Polymeric Micellar Systems with Weak Polyelectrolyte Shells: The Lowering of the pH Value

1997 ◽  
Vol 62 (11) ◽  
pp. 1730-1736 ◽  
Author(s):  
Petr Munk ◽  
Zdeněk Tuzar ◽  
Karel Procházka
Keyword(s):  
Ionic Strength ◽  
Block Copolymer ◽  
Ph Value ◽  
Electrolyte Solutions ◽  
Hydrogen Ions ◽  
Micellar Systems ◽  
Weak Electrolytes ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Polyelectrolyte Solutions

When two electrolyte solutions are separated and only some of the ions can cross the boundary, the concentrations of these ions are different on both sides of the boundary. This is the well-known Donnan effect. When weak electrolytes are involved, the imbalance includes also hydrogen ions: there is a difference of pH across the boundary and the dissociation of nondiffusible weak electrolytes is suppressed. The effect is very pronounced when the concentration of the weak electrolyte is high and ionic strength is low. The significance of this phenomenon is discussed for polyelectrolyte solutions, and particularly for block copolymer micelles with weak polyelectrolyte shells. The effect is quite dramatic in the latter case.

A Monte Carlo Study of Flexible Polymer Chain Conformations in Restricted Volumes. I. A Model for Insoluble Blocks Conformations in Swollen Cores of Multimolecular Spherical Block Copolymer Micelles

1993 ◽  
Vol 58 (10) ◽  
pp. 2290-2304 ◽  
Author(s):  
Zuzana Limpouchová ◽  
Karel Procházka
Keyword(s):  
Monte Carlo ◽  
Block Copolymer ◽  
Monte Carlo Study ◽  
Volume Effect ◽  
Micellar Systems ◽  
Flexible Polymer ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Chain Conformations ◽  
Chain Lengths

Monte Carlo simulations of chain conformations in a restricted spherical volume at relatively high densities of segments were performed for various numbers of chains, N, and chain lengths (number of segments), L, on a tetrahedral lattice. All chains are randomly end-tethered to the surface of the sphere. A relatively uniform surface density of the tethered ends is guaranteed in our simulations. A simultaneous self-avoiding walk of all chains creates starting conformations for a subsequent equilibration. A modified algorithm similar to that of Siepmann and Frenkel is used for the equilibration of the chain conformations. In this paper, only a geometrical excluded volume effect of segments is considered. Various structural and conformational characteristics, e.g. segment densities gS(r), free end densities gF(r) as functions of the position in the sphere (a distance from the center), distributions of the tethered-to-free end distances, ρTF(rTF), etc. are calculated and their physical meaning is discussed. The model is suitable for studies of chain conformations is swollen cores of multimolecular block copolymer micelles and for interpretation of non-radiative excitation energy migration in polymeric micellar systems.

Study of Sedimentation Velocity of Block Copolymer Micelles

1993 ◽  
Vol 58 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Minmin Tian ◽  
C. Ramireddy ◽  
Stephen E. Webber ◽  
Petr Munk
Keyword(s):  
Block Copolymer ◽  
Methacrylic Acid ◽  
Mixed Solvent ◽  
Hard Spheres ◽  
Sedimentation Velocity ◽  
Hydrodynamic Coefficient ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Size Heterogeneity ◽  
Good Agreement

No anomalies were observed during the measurement of sedimentation coefficients of block copolymer micelles formed by copolymers of styrene and methacrylic acid in a mixed solvent; 80 vol.% of dioxane and 20 vol.% of water. The shapes of the sedimenting boundaries suggest that the size heterogeneity of the micelles is small. Linear relations between 1/s and c were obtained. The value of the hydrodynamic coefficient κ was between 2 and 4 in a good agreement with the value 2.75 or 2.86 that was obtained by combining Burgers' or Fixman's values of the coefficient of the concentration dependence kvs for hard spheres with Einstein's value of [η] for spheres.

Chain Exchange Kinetics of Bottlebrush Block Copolymer Micelles

2021 ◽  
Author(s):  
Seyoung Kim ◽  
Sangho Lee ◽  
Soo-Hyung Choi ◽  
Kookheon Char
Keyword(s):  
Block Copolymer ◽  
Block Copolymer Micelles ◽  
Exchange Kinetics ◽  
Copolymer Micelles ◽  
Kinetics Of

Control of the Morphology of Linear and Cyclic PS-b-PI Block Copolymer Micelles via PS Addition

Langmuir ◽  
2005 ◽  
Vol 21 (4) ◽  
pp. 1180-1186 ◽  
Author(s):  
Nadia Ouarti ◽  
Pascal Viville ◽  
Roberto Lazzaroni ◽  
Edson Minatti ◽  
Michel Schappacher ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

Fluorometric and Ultraviolet−Visible Absorption Study of Poly(methacrylic acid) Shells of High-Molar-Mass Block Copolymer Micelles†

Langmuir ◽  
1999 ◽  
Vol 15 (12) ◽  
pp. 4185-4193 ◽  
Author(s):  
Miroslav Štěpánek ◽  
Klára Podhájecká ◽  
Karel Procházka ◽  
Yue Teng ◽  
Stephen E. Webber
Keyword(s):  
Block Copolymer ◽  
Methacrylic Acid ◽  
Molar Mass ◽  
Absorption Study ◽  
Visible Absorption ◽  
High Molar Mass ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles
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