Zeta-Potential Measurements as a Tool To Quantify the Effect of Charged Drugs on the Surface Potential of Egg Phosphatidylcholine Liposomes

Langmuir ◽  
2004 ◽  
Vol 20 (2) ◽  
pp. 369-377 ◽  
Author(s):  
Carla Matos ◽  
Baltazar de Castro ◽  
Paula Gameiro ◽  
José L. F. C. Lima ◽  
Salette Reis
Keyword(s):  
Zeta Potential ◽  
Surface Potential ◽  
Phosphatidylcholine Liposomes

Effect of Different Anions on 22Na Permeability of Liposomes

1973 ◽  
Vol 51 (11) ◽  
pp. 779-784 ◽  
Author(s):  
M. A. Singer
Keyword(s):  
Zeta Potential ◽  
Dipole Potential ◽  
Sodium Permeability ◽  
Phosphatidylcholine Liposomes ◽  
Solution Interface ◽  
Cation Permeability ◽  
Na Efflux ◽  
Negative Zeta Potential

The 22Na efflux from phosphatidylcholine liposomes was measured in the presence of different anions. Only salicylate significantly increases sodium permeability. Although this anion adsorbs onto the liposomal surface creating a negative zeta potential, evidence is presented that this is not the sole mechanism underlying the enhanced cation permeability. It is proposed that salicylate also alters the dipole potential at the membrane–solution interface.

Combined measurement of surface potential and zeta potential at insulator/electrolyte interfaces

1992 ◽  
Vol 10 (1) ◽  
pp. 67-71 ◽  
Author(s):  
Luc J. Bousse ◽  
Shahriar Mostarshed ◽  
Dean Hafeman
Keyword(s):  
Zeta Potential ◽  
Surface Potential

scholarly journals Structure–charge relationship – the case of hematite (001)

2015 ◽  
Vol 180 ◽  
pp. 55-79 ◽  
Author(s):  
Johannes Lützenkirchen ◽  
Frank Heberling ◽  
Filip Supljika ◽  
Tajana Preocanin ◽  
Nikola Kallay ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Surface Structure ◽  
Surface Potential ◽  
Isoelectric Point ◽  
Water Structure ◽  
Aging Effect ◽  
Electrolyte Solutions ◽  
Hydroxyl Groups ◽  
Humid Atmosphere ◽  
Multidisciplinary Study

We present a multidisciplinary study on the hematite (001)–aqueous solution interface, in particular the relationship between surface structure (studiedviasurface diffraction in a humid atmosphere) and the macroscopic charging (studiedviasurface- and zeta-potential measurements in electrolyte solutions as a function of pH). Upon aging in water changes in the surface structure are observed, that are accompanied by drastic changes in the zeta-potential. Surprisingly the surface potential is not accordingly affected. We interpret our results by increasing hydration of the surface with time and enhanced reactivity of singly-coordinated hydroxyl groups that cause the isoelectric point of the surface to shift to values that are reminiscent of those typically reported for hematite particles. In its initial stages after preparation the hematite surface is very flat and only weakly hydrated. Our model links the entailing weak water structure with the observed low isoelectric point reminiscent of hydrophobic surfaces. The absence of an aging effect on the surface potentialvs.pH curves is interpreted as domination of the surface potential by the doubly coordinated hydroxyls, which are present on both surfaces.

scholarly journals The zeta potential calculation for fluid saturated porous media using linearized and nonlinear solutions of Poisson–Boltzmann equation

2018 ◽  
Vol 34 (3) ◽  
Author(s):  
Luong Duy Thanh
Keyword(s):  
Experimental Data ◽  
Boltzmann Equation ◽  
Zeta Potential ◽  
Surface Potential ◽  
Electric Potential ◽  
Small Magnitude ◽  
Nonlinear Solution ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation ◽  
Nonlinear Solutions

Theoretical models have been developed to calculate the zeta potential based on the solution of the linearized approximation of the Poisson-Boltzmann equation (PB). The approximation is only valid for the small magnitude of the surface potential. However, the surface potential available in published experimental data normally does not satisfy that condition. Therefore, the complete analytical solution to the PB equation (nonlinear equation) needs to be considered. In this work, the comparison between the linearized and nonlinear solutions has been performed. The results show that the linearized solution always overestimates the absolute value of the electric potential in the electric double layer as well as the zeta potential. For a small magnitude of the surface potential, the electric potential distribution predicted from the linearized solution is almost the same as that predicted from the nonlinear solution. It is also shown that the zeta potential computed from the linearized PB solution closely matches with that computed from the nonlinear solution for the fluid pH = 5 - 8 and the shear plane distance of 2.4×10−10 m. Therefore, the solution of the linearized PB equation can be used to calculate the zeta potential under that condition. This is validated by comparing the linearized and nonlinear solutions with experimental data in literature.

A radial flow streaming potential apparatus for electrokinetic studies of sheet or plate materials

1981 ◽  
Vol 34 (6) ◽  
pp. 1167 ◽  
Author(s):  
JS Lyons ◽  
DN Furlong ◽  
A Homola ◽  
TW Healy
Keyword(s):  
Zeta Potential ◽  
Double Layer ◽  
Surface Potential ◽  
Salt Concentration ◽  
Radial Flow ◽  
Streaming Potential ◽  
Smoluchowski Equation ◽  
Fused Silica ◽  
Apparatus Design ◽  
Good Agreement

A radial flow streaming potential (r.f.s.p.) apparatus, and the procedure adopted for streaming potential determination, are described. It is shown by consideration of apparatus design and by experiment that the conditions necessary for valid application of the Helmholtz-Smoluchowski equation for zeta-potential calculation are satisfied by the r.f.s.p. technique. Zeta-potential data for fused silica discs determined by the r.f.s.p, technique are found to be in good agreement with previous studies on other forms of silica. Application of the Gouy-Chapman- Stern-Grahame double-layer theory to enable calculation of surface potential (ψo) shows it to be independent of salt concentration and to change by 30 mV per pH unit, both results providing verification of the soundness of the r.f.s.p. technique.

The effects of surface absorbed monolayer microdiffraction patterns

1988 ◽  
Vol 46 ◽  
pp. 680-681
Author(s):  
M. Pan ◽  
J.M. Cowley
Keyword(s):  
Surface Potential ◽  
Electron Probe ◽  
Potential Distribution ◽  
Crystal Surface ◽  
Normal Direction ◽  
Surface Image ◽  
Extended Surface ◽  
Gas Molecules ◽  
Surface Nature ◽  
Electron Microdiffraction

Electron microdiffraction patterns, obtained when a small electron probe with diameter of 10-15 Å is directed to run parallel to and outside a flat crystal surface, are sensitive to the surface nature of the crystals. Dynamical diffraction calculations have shown that most of the experimental observations for a flat (100) face of a MgO crystal, such as the streaking of the central spot in the surface normal direction and (100)-type forbidden reflections etc., could be explained satisfactorily by assuming a modified image potential field outside the crystal surface. However the origin of this extended surface potential remains uncertain. A theoretical analysis by Howie et al suggests that the surface image potential should have a form different from above-mentioned image potential and also be smaller by several orders of magnitude. Nevertheless the surface potential distribution may in practice be modified in various ways, such as by the adsorption of a monolayer of gas molecules.

Glycoproteins IIb and IIIa and Platelet Thrombospondin in a Liposome Model of Platelet Aggregation

1986 ◽  
Vol 55 (02) ◽  
pp. 240-245 ◽  
Author(s):  
M E Rybak
Keyword(s):  
Platelet Aggregation ◽  
Direct Evidence ◽  
Phospholipid Vesicles ◽  
Aggregate Formation ◽  
Membrane Glycoproteins ◽  
Protein Orientation ◽  
Phosphatidylcholine Liposomes ◽  
Calcium Dependent ◽  
Lentil Lectin ◽  
Complete Reversal

SummaryPlatelet membrane glycoproteins IIb and IIIa and platelet thrombospondin were incorporated onto phosphatidylcholine liposomes, by freeze thawing and sonication. Protein orientation on the liposomes was confirmed by susceptibility to neuraminidase cleavage and binding to lentil lectin-Sepharose (GPIIb-IIIa liposomes) and to heparin-Sepharose (thrombospondin liposomes). Glycoproteins Ilb-IIIa bound 125I-fibrinogen with Kd of 7.5 × 10™7M. Binding was reversible and calcium-dependent. Ilb-IIIa liposomes underwent fibrinogen-dependent aggregation in the presence of 10 mM CaCl2. Maximal aggregate formation was observed with a combination of IIb-IIIa liposomes and thrombospondin liposomes. This aggregation was partially inhibited by preincubation with monoclonal antibodies to the IIb-IIIa complex. Addition of EDTA caused complete reversal of aggregates. Thrombospondin liposomes also underwent fibrinogen and calcium dependent aggregation, however, this aggregation was less than that observed with the GPIIb-IIIa liposomes. Maximal aggregate formation was observed with a mixture of IIb-IIIa liposomes and thrombospondin liposomes. These studies demonstrate that GPIIb-IIIa and thrombospondin can be incorporated into phospholipid vesicles with preservation of function. Direct evidence is provided to demonstrate that glycoprotein lib and Ilia and fibrinogen are sufficient for platelet aggregation and to demonstrate that thrombospondin may also contribute to platelet aggregation.

How to use alum with cationic dispersed rosin size

TAPPI Journal ◽  
2016 ◽  
Vol 15 (5) ◽  
pp. 331-335 ◽  
Author(s):  
LEBO XU ◽  
JEREMY MYERS ◽  
PETER HART
Keyword(s):  
Zeta Potential ◽  
Colloidal Particles ◽  
Streaming Potential ◽  
Excessive Amount ◽  
Paper Machine ◽  
Optimum Amount ◽  
Potential Measurement ◽  
Streaming Current ◽  
Wide Range ◽  
Laboratory Results

Retention of cationic dispersed rosin size was studied via turbidity measurements on stock filtrate with different alum and dispersed rosin size dosages. Stock charge characteristics were analyzed using both an analysis of charge demand determined via a streaming current detector and an evaluation of zeta potential of the fibers by streaming potential measurement. The results indicated that an optimum amount of alum existed such that good sizing retention was maintained throughout a wide range of dispersed rosin size dosages. However, when an excessive amount of alum was used and fines and colloidal particles were transitioned from anionic to cationic, the cationic size retention was reduced. Laboratory results were confirmed with a paper machine trial. All data suggested that a stock charge study was necessary to identify optimal alum dosage for a cationic dispersed rosin sizing program.

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