Molecular distribution and charge of polylysine layers at the surface of lipid membranes and mica

Finogenova, O.A.; Batischev, O. V.; Indenbom, A. V.; Zolotarevsky, V. I.; Ermakov, Yu. A.

doi:10.1134/s1990747809040187

Cited by 5 publications

(10 citation statements)

References 8 publications

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“…Thus, according to [ 122 , 123 ], the saturation in the ζ -potential measurements occurred at θ max ≈ 0.5. Our experiments show nearly the same values for adsorption of poly-L-lysine on mica measured by AFM [ 84 ]: θ max ≈ 0.6 for N = 130 and N = 1000. These estimates fit into the concept of the random sequence adsorption (RSA) model.…”

Section: Lateral Heterogeneity Of Polymer Layer As It Follows From the Analysis Of Electrokinetic Datasupporting

confidence: 75%

“…In both cases, there is a sharp rise of the curve near the point of zero charge where the surface is neutral, and the electrostatic interactions are minimized. The magnitude of ζ-potential reaches its maximal value at the saturation level, which depends on the ionic strength and polymer length [ 84 ]. Note that in the case of multivalent cations, ζ-potential has a maximum and then decreases at high ion concentrations, whereas in the case of polylysines, this potential saturates.…”

Section: Inorganic Cations and Polycations In The Electric Fields At The Membrane Boundarymentioning

confidence: 99%

“…It is necessary to note here that electrokinetic measurements are related to the electric potential (ζ-potential) at the slipping plane at a certain distance from the charged surface [ 85 ]. Previously, adsorption of polylysine was measured at low ionic strength, when the ζ-potential becomes close to surface potential [ 84 ]. We accepted this condition to simplify the analysis and to evaluate the surface charge density according to the Smoluchowski relation and equations of the Gouy–Chapman model.…”

Section: Inorganic Cations and Polycations In The Electric Fields At The Membrane Boundarymentioning

confidence: 99%

“…Generally, the application of the Gouy–Chapman model of the electric double layer in its straightforward simplified form to large polycations in [ 84 ] does not stand up to criticism. First of all, this rather simple model assumes the existence of a diffuse part of the electric double layer with the charge coinciding in absolute value with the surface charge of the opposite sign [ 85 , 88 ].…”

Section: Inorganic Cations and Polycations In The Electric Fields At The Membrane Boundarymentioning

confidence: 99%

“…As a result, this approach makes several verifiable predictions about the thickness of the adsorption layer. However, experimental data show a more complex and heterogeneous structure of the adsorption layer [ 84 , 97 ]. For this reason, a scaling theory approach should be expanded to take into account the structural features of the adsorption layer.…”

Section: Conformations Of Linear Polycation At the Charged Surfacementioning

confidence: 99%

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Heterogeneity in Lateral Distribution of Polycations at the Surface of Lipid Membrane: From the Experimental Data to the Theoretical Model

2021

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Natural and synthetic polycations of different kinds attract substantial attention due to an increasing number of their applications in the biomedical industry and in pharmacology. The key characteristic determining the effectiveness of the majority of these applications is the number of macromolecules adsorbed on the surface of biological cells or their lipid models. Their study is complicated by a possible heterogeneity of polymer layer adsorbed on the membrane. Experimental methods reflecting the structure of the layer include the electrokinetic measurements in liposome suspension and the boundary potential of planar bilayer lipid membranes (BLM) and lipid monolayers with a mixed composition of lipids and the ionic media. In the review, we systematically analyze the methods of experimental registration and theoretical description of the laterally heterogeneous structures in the polymer layer published in the literature and in our previous studies. In particular, we consider a model based on classical theory of the electrical double layer, used to analyze the available data of the electrokinetic measurements in liposome suspension with polylysines of varying molecular mass. This model suggests a few parameters related to the heterogeneity of the polymer layer and allows determining the conditions for its appearance at the membrane surface. A further development of this theoretical approach is discussed.

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Section: Lateral Heterogeneity Of Polymer Layer As It Follows From the Analysis Of Electrokinetic Datasupporting

confidence: 75%

Section: Inorganic Cations and Polycations In The Electric Fields At The Membrane Boundarymentioning

confidence: 99%

Section: Inorganic Cations and Polycations In The Electric Fields At The Membrane Boundarymentioning

confidence: 99%

Section: Inorganic Cations and Polycations In The Electric Fields At The Membrane Boundarymentioning

confidence: 99%

Section: Conformations Of Linear Polycation At the Charged Surfacementioning

confidence: 99%

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Heterogeneity in Lateral Distribution of Polycations at the Surface of Lipid Membrane: From the Experimental Data to the Theoretical Model

2021

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Rectification of Concentration Polarization in Mesopores Leads To High Conductance Ionic Diodes and High Performance Osmotic Power

et al. 2019

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Nanopores exhibit a set of interesting transport properties that stem from interactions of the passing ions and molecules with the pore walls. Nanopores are used, for example, as ionic diodes and transistors, biosensors, and osmotic power generators. Using nanopores is however disadvantaged by their high resistance, small switching currents in nA range, low power generated, and signals that can be difficult to distinguish from the background. Here, we present a mesopore with ionic conductance reaching μS that rectifies ion current in salt concentrations as high as 1 M. The mesopore is conically shaped, and its region close to the narrow opening is filled with high molecular weight poly-l-lysine. To elucidate the underlying mechanism of ion current rectification (ICR), a continuum model based on a set of Poisson–Nernst–Planck and Stokes–Brinkman equations was adopted. The results revealed that embedding the polyelectrolyte in a conical pore leads to rectification of the effect of concentration polarization (CP) that is induced by the polyelectrolyte, and observed as voltage polarity-dependent modulations of ionic concentrations in the pore, and consequently ICR. Our work reveals the link between ICR and CP, significantly extending the knowledge of how charged polyelectrolytes modulate ion transport on nano- and mesoscales. The osmotic power application is also demonstrated with the developed polyelectrolyte-filled mesopores, which enable a power of up to ∼120 pW from one pore, which is much higher than the reported values using single nanoscale pores.

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Polymer concentration dependence of kilohertz electric polarizability of alumina colloid particles with adsorbed carboxymethyl cellulose

Zhivkov

Hristov²

2010

J. Phys.: Condens. Matter

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Polyelectrolytes are soluble polymers composed of units having charged groups. Because of the high charge density, some of the counterions are adsorbed electrostatically (ion condensation) on the polyelectrolyte chain. It was shown that in direct electric field the condensed counterions and the chain move together as one whole but it is assumed that they are mobile in alternating field and participate in the polarization. Experimental evidence is obtained by electro-optical investigations of polyelectrolytes adsorbed on colloid particles-the observed low-frequency shift of the polarizability relaxation has been interpreted as condensed counterions' mobility. The present investigation aims to verify the reports for the condensed counterions' mobility in sinusoidal electric field. By means of electric light scattering we investigated a water suspension of γ-alumina particles with adsorbed carboxymethyl cellulose. Instead of the previously used frequency approach (dispersion dependence at saturated adsorption of the polyelectrolyte) we applied an amplitude approach-determination of the polarizability at frequency 1 kHz and increasing polyelectrolyte concentration (from zero to full adsorption saturation). The results indicate the absence of polarization owing to the condensed counterions. The main evidence was obtained by comparison of the concentration dependences of the polarizability (depending on all mobile counterions) and the electrophoretic mobility (determined only by the diffuse counterions). We concluded that the condensed counterions are immobile in sinusoidal field with intensity up to 0.5 kV cm (- 1) and frequency of 1 kHz and higher.

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Molecular distribution and charge of polylysine layers at the surface of lipid membranes and mica

Cited by 5 publications

References 8 publications

Heterogeneity in Lateral Distribution of Polycations at the Surface of Lipid Membrane: From the Experimental Data to the Theoretical Model

Heterogeneity in Lateral Distribution of Polycations at the Surface of Lipid Membrane: From the Experimental Data to the Theoretical Model

Rectification of Concentration Polarization in Mesopores Leads To High Conductance Ionic Diodes and High Performance Osmotic Power

Polymer concentration dependence of kilohertz electric polarizability of alumina colloid particles with adsorbed carboxymethyl cellulose

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