Charge regulation of colloidal particles in aqueous solutions

Bakhshandeh, Amin; Frydel, Derek; Levin, Yan

doi:10.1039/d0cp03633a

Cited by 28 publications

(55 citation statements)

References 90 publications

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“…Specifically, can a protein's net charge (Z) be altered by the charge of its neighbor via charge regulation? [13][14][15] Monte Carlo simulations of protein crowding (at low ionic strength) suggest the answer to be yes. 13 Based upon the role of protein charge in catalysis, molecular recognition, and aggregation, 16,17 these theoretical results suggest that the function or dysfunction of a protein can be controlled by the charge of its neighbors, assuming that they are sufficiently crowded and at low ionic strength.…”

Section: Introductionmentioning

confidence: 99%

“…One question that has been lurking in the field of protein electrostatics, experimentally unanswered, is: how are the electrostatic properties of a protein affected intermolecularly, by the net charge (electric field) of its neighbors in a crowded environment? Specifically, can a protein's net charge ( Z ) be altered by the charge of its neighbor via charge regulation ? 13–15 Monte Carlo simulations of protein crowding (at low ionic strength) suggest the answer to be yes 13 . Based upon the role of protein charge in catalysis, molecular recognition, and aggregation, 16,17 these theoretical results suggest that the function or dysfunction of a protein can be controlled by the charge of its neighbors, assuming that they are sufficiently crowded and at low ionic strength.…”

Section: Introductionmentioning

confidence: 99%

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Measuring how two proteins affect each other's net charge in a crowded environment

et al. 2021

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Theory predicts that the net charge (Z) of a protein can be altered by the net charge of a neighboring protein as the two approach one another below the Debye length. This type of charge regulation suggests that a protein's charge and perhaps function might be affected by neighboring proteins without direct binding. Charge regulation during protein crowding has never been directly measured due to analytical challenges. Here, we show that lysine specific protein crosslinkers (NHS ester-Staudinger pairs) can be used to mimic crowding by linking two non-interacting proteins at a maximal distance of $7.9 Å. The net charge of the regioisomeric dimers and preceding monomers can then be determined with lysine-acyl "protein charge ladders" and capillary electrophoresis. As a proof of concept, we covalently linked myoglobin (Z monomer = À0.43 ± 0.01) and α-lactalbumin (Z monomer = À4.63 ± 0.05). Amide hydrogen/deuterium exchange and circular dichroism spectroscopy demonstrated that crosslinking did not significantly alter the structure of either protein or result in direct binding (thus mimicking crowding). Ultimately, capillary electrophoretic analysis of the dimeric charge ladder detected a change in charge of ΔZ = À0.04 ± 0.09 upon crowding by this pair (Z dimer = À5.10 ± 0.07). These small values of ΔZ are not necessarily general to protein crowding (qualitatively or quantitatively) but will vary per protein size, charge, and solvent conditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Measuring how two proteins affect each other's net charge in a crowded environment

et al. 2021

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“…For weakly charged surfaces or on sufficiently small length scales, the discreteness of the electric charge will become noticeable. This has inspired a number of authors to compute the electrostatic potential produced by an ordered array of surface charges [19][20][21] or even a single surface charge [22][23][24][25] and others to use virial expansions [26,27] and Monte Carlo simulations [28][29][30][31][32][33][34][35][36][37] to account for charge discreteness. Some studies have focused on the pressure that acts across electrolytes due to the presence of discrete charges [28,35,38], yet-perhaps somewhat surprisingly-there has not been an attempt so far to compute the free energy of a single planar dielectric interface with discrete charges and compare this with the corresponding free energy derived for a continuous charge distribution.…”

Section: Introductionmentioning

confidence: 99%

Debye-Hückel Free Energy of an Electric Double Layer with Discrete Charges Located at a Dielectric Interface

Bossa

May

2021

Membranes

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Poisson–Boltzmann theory provides an established framework to calculate properties and free energies of an electric double layer, especially for simple geometries and interfaces that carry continuous charge densities. At sufficiently small length scales, however, the discreteness of the surface charges cannot be neglected. We consider a planar dielectric interface that separates a salt-containing aqueous phase from a medium of low dielectric constant and carries discrete surface charges of fixed density. Within the linear Debye-Hückel limit of Poisson–Boltzmann theory, we calculate the surface potential inside a Wigner–Seitz cell that is produced by all surface charges outside the cell using a Fourier-Bessel series and a Hankel transformation. From the surface potential, we obtain the Debye-Hückel free energy of the electric double layer, which we compare with the corresponding expression in the continuum limit. Differences arise for sufficiently small charge densities, where we show that the dominating interaction is dipolar, arising from the dipoles formed by the surface charges and associated counterions. This interaction propagates through the medium of a low dielectric constant and alters the continuum power of two dependence of the free energy on the surface charge density to a power of 2.5 law.

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“…That means differences exist in the potential/charge fields responsible for interactions. Depending on the nature and mechanism of surface charge regulation (Ong et al, 2020;Bakhshandeh, 2020), it is possible to have electrostatic systems with specific ranges of potential, from dilute solutions (Konovalov & Ryzhkina, 2014) with low surface potentials to concentrated solutions with high surface potentials (Wennerström et al, 2017). The former range of potential is the basis for the identification and formulation of the linearized LPB equation.…”

Section: Introductionmentioning

confidence: 99%

Applicability of the Linearized Poisson-Boltzmann Theory to Contact Angle problems and Application to the Carbon Dioxide-Brine-Solid Systems

Amadu

Midanoye

2021

Preprint

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In colloidal science and bioelectrostatics, the linear Poisson Boltzmann Equation (LPBE) has been used extensively for the calculation of potential and surface charge density. Its fundamental assumption rests on the premises of low surface potential. In the geological sequestration of carbon dioxide in saline aquifers, very low pH conditions coupled with adsorption induced reduction of surface charge density result in low pH conditions that fit into the LPB theory. In this work, the Gouy-Chapman model of the electrical double layer has been employed in addition to the LPBE theory to develop a contact angle model that is a second-degree polynomial in pH. Our model contains the point of zero charge pH of solid surface. To render the model applicable to heterogeneous surfaces, we have further developed a model for the effective value of the point of zero charge pH. The point of zero charge pH model when integrated into our model enabled us to determine the point of zero charge pH of sandstone, quartz and mica using literature based experimental data. In this regard, a literature based thermodynamic model was used to calculate carbon dioxide solubility and pH of aqueous solution. Values of point of zero charge pH determined in this paper agree with reported ones. The novelty of our work stems from the fact that we have used the LPB theory in the context of interfacial science completely different from the classical approach, where the focus is on interparticle electrostatics involving colloidal stabilization.

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Charge regulation of colloidal particles in aqueous solutions

Abstract: We study charge regulation of colloidal particles inside aqueous electrolyte solutions. To stabilize colloidal suspension against precipitation, colloidal particles are synthesized with either acidic or basic groups on their surface....

Cited by 28 publications

References 90 publications

Measuring how two proteins affect each other's net charge in a crowded environment

Measuring how two proteins affect each other's net charge in a crowded environment

Debye-Hückel Free Energy of an Electric Double Layer with Discrete Charges Located at a Dielectric Interface

Applicability of the Linearized Poisson-Boltzmann Theory to Contact Angle problems and Application to the Carbon Dioxide-Brine-Solid Systems

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