Intermolecular Interactions in Polyelectrolyte and Surfactant Complexes in Solution

Polyelectrolytes are an important class of polymeric materials and are increasingly used in complex industrial formulations. A core use of these materials is in mixtures with surfactants, where a combination of hydrophobic and electrostatic interactions drives unique solution behavior and structure formation. In this review, we apply a molecular level perspective to the broad literature on polyelectrolyte-surfactant complexes, discussing explicitly the hydrophobic and electrostatic interaction contributions to polyelectrolyte surfactant complexes (PESCs), as well as the interplay between the two molecular interaction types. These interactions are sensitive to a variety of solution conditions, such as pH, ionic strength, mixing procedure, charge density, etc. and these parameters can readily be used to control the concentration at which structures form as well as the type of structure in the bulk solution.

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Molecular tapes in the structure of isoguaninium chloride

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229617017685 ◽

2017 ◽

Vol 74 (1) ◽

pp. 108-112 ◽

Cited By ~ 1

Author(s):

Urszula Anna Budniak ◽

Paulina Maria Dominiak

Keyword(s):

Crystal Structure ◽

Single Crystal ◽

Charge Density ◽

Interaction Energy ◽

Electrostatic Interaction ◽

Electrostatic Interactions ◽

The Other ◽

X Ray Diffraction ◽

X Ray ◽

Diffraction Structure

Isoguanine, an analogue of guanine, is of intrinsic interest as a noncanonical nucleobase. The crystal structure of isoguaninium chloride (systematic name: 6-amino-2-oxo-1H,7H-purin-3-ium chloride), C5H6N5O+·Cl−, has been determined by single-crystal X-ray diffraction. Structure analysis was supported by electrostatic interaction energy (E es) calculations based on charge density reconstructed with the UBDB databank. In the structure, two kinds of molecular tapes are observed, one parallel to (010) and the other parallel to (50\overline{4}). The tapes are formed by dimers of isoguaninium cations interacting with chloride anions. E es analysis indicates that cations in one kind of tape are oriented so as to minimize repulsive electrostatic interactions.

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Adjacent cationic–aromatic sequences yield strong electrostatic adhesion of hydrogels in seawater

Nature Communications ◽

10.1038/s41467-019-13171-9 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 18

Author(s):

Hailong Fan ◽

Jiahui Wang ◽

Zhen Tao ◽

Junchao Huang ◽

Ping Rao ◽

...

Keyword(s):

Ionic Strength ◽

Electrostatic Interaction ◽

Electrostatic Interactions ◽

Saline Water ◽

Aromatic Amino Acids ◽

High Ionic Strength ◽

Polymer Materials ◽

Specific Sequence ◽

Charged Surfaces ◽

Π Complex

Abstract Electrostatic interaction is strong but usually diminishes in high ionic-strength environments. Biosystems can use this interaction through adjacent cationic–aromatic amino acids sequence of proteins even in a saline medium. Application of such specific sequence to the development of cationic polymer materials adhesive to negatively charged surfaces in saline environments is challenging due to the difficulty in controlling the copolymer sequences. Here, we discover that copolymers with adjacent cation–aromatic sequences can be synthesized through cation–π complex-aided free-radical polymerization. Sequence controlled hydrogels from diverse cation/aromatic monomers exhibit fast, strong but reversible adhesion to negatively charged surfaces in seawater. Aromatics on copolymers are found to enhance the electrostatic interactions of their adjacent cationic residues to the counter surfaces, even in a high ionic-strength medium that screens the electrostatic interaction for common polyelectrolytes. This work opens a pathway to develop adhesives using saline water.

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Charge density studies of interactions in macromolecules – the case of sunitinib

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314090299 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C970-C970

Author(s):

Maura Malińska ◽

Katarzyna Jarzembska ◽

Anna Goral ◽

Andrzej Kutner ◽

Krzysztof Woźniak ◽

...

Keyword(s):

Charge Density ◽

Interaction Energy ◽

Electron Density ◽

Electrostatic Interaction ◽

Tyrosine Kinases ◽

Electrostatic Interactions ◽

Kinase Inhibitor ◽

Topological Analysis ◽

3D Structure ◽

X Ray

Electron density is a key factor in determining properties of molecules. Knowledge of the electron density distribution allows to determine not only the 3D structure of molecules, but also various one-electron properties (electric moments, electrostatic potential, electrostatic interaction energy, etc.). X-ray diffraction is a great tool for obtaining this kind of information. For macromolecules, however, quantitative determination of charge density from experiment is possible on rare occasions only. We will present that with the University at Buffalo pseudoatom database (UBDB) approach [1,2] it is now possible to reconstruct electron density of any macromolecular system for which atomic coordinates are available. The approach is fast and opens an excellent opportunity to investigate macromolecular complexes by means of topological analysis of electron density (and derivatives thereof), electrostatic interaction energy analysis, and many others. The results of our studies on sunitinib (SU) will illustrate the possibilities of the approach. SU is an inhibitor of tyrosine kinases and was approved as a drug in 2006. Comprehensive analysis of the SU malate crystal and SU complexes with a series of protein kinases was carried out. The high resolution single crystal X-ray measurement and UBDB approach served as the basis for the reconstruction of the charge density of SU and the protein complexes. Hirshfeld surface and topological analyses revealed a similar interaction pattern in the SU malate crystal to that in the protein binding pockets. SU forms nine preserved bond paths corresponding to hydrogen bonds and also to the C-H...O and C-H...π contacts common for all analyzed kinases. It interacts typically with similar electrostatic interaction energy with the studied proteins and can adjust its conformation to fit the binding pocket in a way to enhance the electrostatic interactions. Such behavior can be responsible for a broad spectrum of action of SU as kinase inhibitor.

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Sulfonate-Functionalized Mesoporous Silica Nanoparticles as Carriers for Controlled Herbicide Diquat Dibromide Release through Electrostatic Interaction

International Journal of Molecular Sciences ◽

10.3390/ijms20061330 ◽

2019 ◽

Vol 20 (6) ◽

pp. 1330 ◽

Cited By ~ 11

Author(s):

Yongpan Shan ◽

Lidong Cao ◽

Chunli Xu ◽

Pengyue Zhao ◽

Chong Cao ◽

...

Keyword(s):

Ionic Strength ◽

Mesoporous Silica ◽

Silica Nanoparticles ◽

Electrostatic Interaction ◽

Electrostatic Interactions ◽

Hydrophobic Interactions ◽

Mesoporous Silica Nanoparticles ◽

Epoxy Group ◽

Herbicidal Activity ◽

Sulfonate Group

Environmental stimuli-responsive pesticide release is desirable for enhanced efficiency and reduced side effects. In most cases, the loading and release of pesticides mainly depends on hydrophobic interactions and hydrogen bonding. Electrostatic interaction is less investigated as a weapon for achieving high loading content and controlled pesticide release. In this work, negative-charge decorated mesoporous silica nanoparticles (MSNs) were facilely fabricated by introducing sulfonate groups onto MSNs through a post-grafting method. Sulfonate-functionalized MSNs (MSN-SO3) were synthesized by conversion of epoxy group into sulfonate group using a bisulfite ion as a ring opening reagent. Diquat dibromide (DQ), one of the globally used quaternary ammonium herbicides, was efficiently loaded into these negatively charged MSN-SO3 nanoparticles. The loading content was increased to 12.73% compared to those using bare MSNs as carriers (5.31%). The release of DQ from DQ@MSN-SO3 nanoparticles was pH and ionic strength responsive, which was chiefly governed by the electrostatic interactions. Moreover, DQ@MSN-SO3 nanoparticles exhibited good herbicidal activity for the control of Datura stramonium L., and the bioactivity was affected by the ionic strength of the release medium. The strategy of cargo loading and release dependent on the electrostatic interactions could be generally used for charge-carrying pesticides using carriers possessing opposite charges to mitigate the potential negative impacts on the environment.

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Interaction of DNA with Cationic Micelles: Effects of Micelle Surface Charge Density, Micelle Shape, and Ionic Strength on Complexation and DNA Collapse

Langmuir ◽

10.1021/la0010673 ◽

2001 ◽

Vol 17 (5) ◽

pp. 1670-1673 ◽

Cited By ~ 50

Author(s):

Yilin Wang ◽

Paul L. Dubin ◽

Huiwen Zhang

Keyword(s):

Ionic Strength ◽

Charge Density ◽

Surface Charge ◽

Surface Charge Density ◽

Cationic Micelles ◽

Micelle Surface

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Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.2.59 ◽

2011 ◽

Vol 2 ◽

pp. 552-560 ◽

Cited By ~ 40

Author(s):

Miriam Jaafar ◽

Oscar Iglesias-Freire ◽

Luis Serrano-Ramón ◽

Manuel Ricardo Ibarra ◽

Jose Maria de Teresa ◽

...

Keyword(s):

Long Range ◽

Electrostatic Interaction ◽

Electrostatic Interactions ◽

Magnetic Force Microscopy ◽

Magnetic Force ◽

Superparamagnetic Nanoparticles ◽

Kelvin Probe Force Microscopy ◽

Magnetic Interactions ◽

Kelvin Probe ◽

Force Microscopy

The most outstanding feature of scanning force microscopy (SFM) is its capability to detect various different short and long range interactions. In particular, magnetic force microscopy (MFM) is used to characterize the domain configuration in ferromagnetic materials such as thin films grown by physical techniques or ferromagnetic nanostructures. It is a usual procedure to separate the topography and the magnetic signal by scanning at a lift distance of 25–50 nm such that the long range tip–sample interactions dominate. Nowadays, MFM is becoming a valuable technique to detect weak magnetic fields arising from low dimensional complex systems such as organic nanomagnets, superparamagnetic nanoparticles, carbon-based materials, etc. In all these cases, the magnetic nanocomponents and the substrate supporting them present quite different electronic behavior, i.e., they exhibit large surface potential differences causing heterogeneous electrostatic interaction between the tip and the sample that could be interpreted as a magnetic interaction. To distinguish clearly the origin of the tip–sample forces we propose to use a combination of Kelvin probe force microscopy (KPFM) and MFM. The KPFM technique allows us to compensate in real time the electrostatic forces between the tip and the sample by minimizing the electrostatic contribution to the frequency shift signal. This is a great challenge in samples with low magnetic moment. In this work we studied an array of Co nanostructures that exhibit high electrostatic interaction with the MFM tip. Thanks to the use of the KPFM/MFM system we were able to separate the electric and magnetic interactions between the tip and the sample.

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Hydrodynamic Modeling of NOM Transport in UF: Effects of Charge Density and Ionic Strength on Effective Size and Sieving

Environmental Science & Technology ◽

10.1021/es900259r ◽

2009 ◽

Vol 43 (14) ◽

pp. 5449-5454 ◽

Cited By ~ 6

Author(s):

Yanxiao Yuan ◽

James E. Kilduff

Keyword(s):

Ionic Strength ◽

Charge Density ◽

Hydrodynamic Modeling ◽

Effective Size

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Anomalous Salt Dependence Reveals an Interplay of Attractive and Repulsive Electrostatic Interactions in α-synuclein Fibril Formation

QRB Discovery ◽

10.1017/qrd.2020.7 ◽

2020 ◽

Vol 1 ◽

Cited By ~ 1

Author(s):

Ricardo Gaspar ◽

Mikael Lund ◽

Emma Sparr ◽

Sara Linse

Keyword(s):

Ionic Strength ◽

Electrostatic Interactions ◽

Intrinsically Disordered Protein ◽

Lipid Vesicles ◽

Intrinsically Disordered ◽

Catalytic Surfaces ◽

Disordered Protein ◽

Salt Dependence ◽

Fluorescence Measurements ◽

The One

Abstractα-Synuclein (α-syn) is an intrinsically disordered protein with a highly asymmetric charge distribution, whose aggregation is linked to Parkinson’s disease. The effect of ionic strength was investigated at mildly acidic pH (5.5) in the presence of catalytic surfaces in the form of α-syn seeds or anionic lipid vesicles using thioflavin T fluorescence measurements. Similar trends were observed with both surfaces: increasing ionic strength reduced the rate of α-syn aggregation although the surfaces as well as α-syn have a net negative charge at pH 5.5. This anomalous salt dependence implies that short-range attractive electrostatic interactions are critical for secondary nucleation as well as heterogeneous primary nucleation. Such interactions were confirmed in Monte Carlo simulations of α-syn monomers interacting with surface-grafted C-terminal tails, and found to be weakened in the presence of salt. Thus, nucleation of α-syn aggregation depends critically on an attractive electrostatic component that is screened by salt to the extent that it outweighs the screening of the long-range repulsion between negatively charged monomers and negative surfaces. Interactions between the positively charged N-termini of α-syn monomers on the one hand, and the negatively C-termini of α-syn on fibrils or vesicles surfaces on the other hand, are thus critical for nucleation.

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