Showing papers by "Boris I Shklovskii published in 2001"
TL;DR: In this article, a polyelectrolyte (PE) molecule with oppositely charged spherical particles such as colloids, micelles, or globular proteins in a salty water solution is studied.
Abstract: Complexation of a long flexible polyelectrolyte (PE) molecule with oppositely charged spherical particles such as colloids, micelles, or globular proteins in a salty water solution is studied. PE binds spheres winding around them, while spheres repel each other and form almost periodic necklace. If the total charge of PE in the solution is larger than total charge of spheres, repulsive correlations of PE turns on a sphere lead to inversion of the net charge of each sphere. In the opposite case when the total charge of spheres is larger, we predict another correlation effect; spheres bind to the PE in such a great number that they invert the charge of the PE. The inverted charge by absolute value can be larger than the bare charge of PE even when screening by monovalent salt is weak. At larger concentrations of monovalent salt, the inverted charge can reach giant proportions. Near the isoelectric point where total charges of spheres and PE are equal, necklaces condense into macroscopic bundles. Our theory ...
139 citations
TL;DR: Phenomenological theory of the phase diagram of reentrant condensation and charge inversion is suggested and it is shown that an important part of the effect of a monovalent salt...
Abstract: The phase diagram of a water solution of DNA and oppositely charged spherical macroions is studied. DNA winds around spheres to form beads-on-a-string complexes resembling the chromatin 10 nm fiber. At small enough concentration of spheres these “artificial chromatin” complexes are negative, while at large enough concentrations of spheres the charge of DNA is inverted by the adsorbed spheres. Charges of complexes stabilize their solutions. In the plane of concentrations of DNA and spheres the phases with positive and negative complexes are separated by another phase, which contains the condensate of neutral DNA–spheres complexes. Thus, when the concentration of spheres grows, DNA–spheres complexes experience condensation and resolubilization (or reentrant condensation). Phenomenological theory of the phase diagram of reentrant condensation and charge inversion is suggested. Parameters of this theory are calculated by microscopic theory. It is shown that an important part of the effect of a monovalent salt on the phase diagram can be described by the nontrivial renormalization of the effective linear charge density of DNA wound around a sphere, due to the Onsager–Manning condensation. We argue that our phenomenological phase diagram or reentrant condensation is generic to a large class of strongly asymmetric electrolytes. Possible implications of these results for the natural chromatin are discussed.
118 citations
TL;DR: In this paper, a polyelectrolyte with an oppositely charged spherical macroion is studied for both salt-free and salty solutions and it is shown that the repulsive correlations of turns lead to the charge inversion.
Abstract: Complexation of a polyelectrolyte with an oppositely charged spherical macroion is studied for both salt-free and salty solutions. When a polyelectrolyte winds around the macroion, its turns repel each other and form an almost equidistant solenoid. It is shown that this repulsive correlations of turns lead to the charge inversion: more polyelectrolyte winds around the macroion than it is necessary to neutralize it. The charge inversion becomes stronger with increasing concentration of salt and can exceed 100%. Monte-Carlo simulation results agree with our analytical theory.
113 citations
TL;DR: It is shown analytically that when the bare charge of the macroion increases, its net charge including the adsorbed counterions oscillates with the number of their layers, and oscillations of capacitance of this electrode with thenumber of adsorbing layers of multivalent counterions.
Abstract: Adsorption of multivalent counterions on the charged surface of a macroion is known to lead to inversion of the macroion charge due to the strong lateral correlations of counterions. We consider a nontrivial role of the excluded volume of counterions on this effect. It is shown analytically that when the bare charge of the macroion increases, its net charge including the adsorbed counterions oscillates with the number of their layers. Charge inversion vanishes every time the top layer of counterions is completely full and becomes incompressible. These oscillations of charge inversion are confirmed by Monte Carlo simulations. Another version of this phenomenon is studied for a metallic electrode screened by multivalent counterions when the potential of the electrode is controlled instead of its charge. In this case, oscillations of the compressibility and charge inversion lead to oscillations of capacitance of this electrode with the number of adsorbed layers of multivalent counterions.
28 citations
TL;DR: In this article, a strongly charged particle (a macroion) binds so many counterions that its net charge changes sign as shown below the binding energy of a counterion with large charge Z is larger than k B T, so that this net charge is easily observable.
Abstract: Charge inversion is a counterintuitive phenomenon in which a strongly charged particle (a macroion) binds so many counterions that its net charge changes sign As shown below the binding energy of a counterion with large charge Z is larger than k B T, so that this net charge is easily observable: it is the net charge that determines a particle drift in a weak field electrophoresis Charge inversion is possible for a variety of macroions, ranging from the charged surface of mica to charged lipid membranes, colloids, DNA or actin Multivalent metal ions, small colloidal particles, charged micelles, short or long polyelectrolytes including DNA can play the role of multivalent counterions Recently charge inversion has attracted significant attention [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]
5 citations
Posted Content•
TL;DR: In this article, the authors review recent advances in the physics of strongly interacting charged systems functioning in water at room temperature, focusing on the phenomena which go beyond the framework of mean field theories, whether linear Debye-Huckel or nonlinear Poisson-Boltzmann.
Abstract: We review recent advances in the physics of strongly interacting charged systems functioning in water at room temperature. We concentrate on the phenomena which go beyond the framework of mean field theories, whether linear Debye-Huckel or non-linear Poisson-Boltzmann. We place major emphasis on charge inversion - a counterintuitive phenomenon in which a strongly charged particle, called macroion, binds so many counterions that its net charge changes sign. We discuss the universal theory of charge inversion based on the idea of a strongly correlated liquid of adsorbed counterions, similar to a Wigner crystal. This theory has a vast array of applications, particularly in biology and chemistry; for example, the DNA double helix in the presence of positive multivalent ions (e.g., polycations) acquires a net positive charge and drifts as a positive particle in electric field. This simplifies DNA uptake by the cell as needed for gene therapy, because the cell membrane is negatively charged. We discuss also the analogies of charge inversion in other fields of physics.
3 citations