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

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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Intermolecular Interactions in Polyelectrolyte and Surfactant Complexes in Solution

Polymers ◽

10.3390/polym11010051 ◽

2018 ◽

Vol 11 (1) ◽

pp. 51 ◽

Cited By ~ 27

Author(s):

Nasreen Khan ◽

Blair Brettmann

Keyword(s):

Ionic Strength ◽

Charge Density ◽

Unique Solution ◽

Electrostatic Interaction ◽

Molecular Interaction ◽

Electrostatic Interactions ◽

Molecular Level ◽

Polymeric Materials ◽

Bulk Solution ◽

Important Class

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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Globular and asymmetric acetylcholinesterase in the synaptic basal lamina of skeletal muscle.

The Journal of Cell Biology ◽

10.1083/jcb.125.1.183 ◽

1994 ◽

Vol 125 (1) ◽

pp. 183-196 ◽

Cited By ~ 22

Author(s):

L Anglister ◽

B Haesaert ◽

U J McMahan

Keyword(s):

Ionic Strength ◽

Cell Surface ◽

Basal Lamina ◽

Ache Activity ◽

Electrostatic Interactions ◽

Neuromuscular Junctions ◽

Hydrophobic Interactions ◽

High Ionic Strength ◽

Molecular Forms ◽

Cellular Components

The aim of this study was to characterize the molecular forms of acetylcholinesterase (AChE) associated with the synaptic basal lamina at the neuromuscular junction. The observations were made on the neuromuscular junctions of cutaneous pectoris muscles of frog, Rana pipiens, which are similar to junctions of most other vertebrates including mammals, but are especially convenient for experimentation. By measuring relative AChE activity in junctional and extrajunctional regions of muscles after selective inactivation of extracellular AChE with echothiophate, or of intracellular AChE with DFP and 2-PAM, we found that > 66% of the total AChE activity in the muscle was junction-specific, and that > 50% of the junction-specific AChE was on the cell surface. More than 80% of the cell surface AChE was solubilized in high ionic strength detergent-free buffer, indicating that most, if not all, was a component of the synaptic basal lamina. Sedimentation analysis of that fraction indicated that while asymmetric forms (A12, A8) were abundant, globular forms sedimenting at 4-6 S (G1 and G2), composed > 50% of the AChE. It was also found that when muscles were damaged in various ways that caused degeneration of axons and muscle fibers but left intact the basal lamina sheaths, the small globular forms persisted at the synaptic site for weeks after phagocytosis of cellular components; under certain damage conditions, the proportion of globular to asymmetric forms in the vacated basal lamina sheaths was as in normal junctions. While the asymmetric forms required high ionic strength for solubilization, the extracellular globular AChE could be extracted from the junctional regions of normal and damaged muscles by isotonic buffer. Some of the globular AChE appeared to be amphiphilic when examined in detergents, suggesting that it may form hydrophobic interactions, but most was non-amphiphilic consistent with the possibility that it forms weak electrostatic interactions. We conclude that the major form of AChE in frog synaptic basal lamina is globular and that its mode of association with the basal lamina differs from that of the asymmetric forms.

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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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Importance of Protease Inhibition in Studies on Purified Factor VIII (Antihaemophilic Factor)

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647943 ◽

1976 ◽

Vol 35 (01) ◽

pp. 186-190 ◽

Cited By ~ 6

Author(s):

Eugen A. Beck ◽

Peter Bachmann ◽

Peter Barbier ◽

Miha Furlan

Keyword(s):

Ionic Strength ◽

Factor Viii ◽

Gel Filtration ◽

High Ionic Strength ◽

Procoagulant Activity ◽

Carrier Protein ◽

Protease Inhibition ◽

Functional Sites ◽

Molecular Weight Peak ◽

Von Willebrand

SummaryAccording to some authors factor VIII procoagulant activity may be dissociable from carrier protein (MW~ 2 × 106) by agarose gel filtration, e.g. at high ionic strength. We were able to reproduce this phenomenon. However, addition of protease inhibitor (Trasylol) prevented the appearance of low molecular weight peak of factor VIII procoagulant activity both at high ionic strength and elevated temperature (37°C). We conclude from our results that procoagulant activity and carrier protein (von Willebrand factor, factor VIII antigen) are closely associated functional sites of native factor VIII macro molecule. Consequently, proteolytic degradation should be avoided in functional and structural studies on factor VIII and especially in preparing factor VIII concentrate for therapeutic use.

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THE RELATIVE DISTRIBUTION OF THYROXINE, TRIIODOTHYRONINE AND 3,3′,5′-(REVERSE)-TRIIODOTHYRONINE IN VARIOUS FRACTIONS OF THYROGLOBULIN

Acta Endocrinologica ◽

10.1530/acta.0.0880298 ◽

1978 ◽

Vol 88 (2) ◽

pp. 298-305 ◽

Cited By ~ 2

Author(s):

Peter Laurberg

Keyword(s):

Ionic Strength ◽

Guinea Pig ◽

Sucrose Gradient ◽

Deae Cellulose ◽

High Ionic Strength ◽

Relative Distribution ◽

Thyroid Extract ◽

Reverse Triiodothyronine ◽

Thyroid Secretion ◽

Stable Iodine

ABSTRACT Thyroglobulin fractions rich and poor in new thyroglobulin were separated by means of DEAE-cellulose chromatography of dog thyroid extracts and by zonal ultracentrifugation in a sucrose gradient of guinea pig thyroid extract incubated at low temperature. The distribution of thyroxine, triiodothyronine and 3,3′,5′-(reverse)-triiodothyronine in hydrolysates of the different fractions was estimated by radioimmunoassays. Following DEAE-cellulose chromatography there was a small but statistically significant increase in the T4/T3 ratio in thyroglobulin fractions eluted at high ionic strength - that is fractions relatively rich in stable iodine but poor in fresh thyroglobulin. There were no differences in the T4/rT3 ratios between the different fractions. The ratios between iodothyronines were almost identical in the various thyroglobulin fractions following zonal ultracentrifugation in a sucrose gradient of cold treated guinea pig thyroid extract. These findings lend no support to the possibility that a relatively high content of triiodothyronines in freshly synthesized thyroglobulin modulates the thyroid secretion towards a preferential secretion of triiodothyronine and 3,3′,5′-(reverse)-triiodothyronine at the expense of the secretion of thyroxine.

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Kaolin based protective barrier in municipal landfills against adverse chemo-mechanical loadings

Scientific Reports ◽

10.1038/s41598-021-89787-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Partha Das ◽

Tadikonda Venkata Bharat

Keyword(s):

Ionic Strength ◽

High Ionic Strength ◽

The Self ◽

Design Parameters ◽

Layered System ◽

Geosynthetic Clay Liners ◽

Clay Liners ◽

Landfill Liner ◽

First Time ◽

Applied Stresses

AbstractIn this work, we assess the self-sealing and swelling ability of the compacted granular bentonite (GB) under an inorganic salt environment and induced overburden stresses from the landfill waste. The laboratory permeation tests with high ionic strength salt solutions reveal that the GB fails to seal and exhibits a significant mechanical collapse under different applied stresses. The applicability of GB in the form of geosynthetic clay liners as the bottom liner facilities in landfills that produce high ionic strength salt leachates, therefore, remains a serious concern. We propose an additional barrier system based on kaolin, for the first time, to address this problem. The proposed kaolin-GB layered system performs satisfactorily in terms of its sealing and swelling ability even in adverse saline conditions and low overburden stresses. The kaolin improves the osmotic efficiency of the self and also helps the underlying GB layer to seal the inter-granular voids. The estimated design parameters by through-diffusion test suggest that the kaolin-GB layered system effectively attenuates the permeant flux and suitable as a landfill liner.

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High ionic strength dissociation assay (HISDA) for high drug tolerant immunogenicity testing

Bioanalysis ◽

10.4155/bio-2020-0138 ◽

2020 ◽

Author(s):

Gregor Jordan ◽

Alexander Pöhler ◽

Florence Guilhot ◽

Meike Zaspel ◽

Roland F Staack

Keyword(s):

Ionic Strength ◽

Acid Treatment ◽

Structural Integrity ◽

Drug Tolerance ◽

High Ionic Strength ◽

Acid Dissociation ◽

High Drug ◽

Overnight Incubation ◽

Antidrug Antibody ◽

High Doses

Aim: Antidrug antibody (ADA) assessment may be challenged in studies that involve the administration of high doses of biotherapeutics and/or with long half-lives. In such cases, ADA assays with optimized drug tolerance are desired. Material & Methods: We evaluated the use of MgCl2 to develop high ionic strength dissociation assays in two investigational examples (bridging enzyme-linked immunosorbent ADA assays) to attain high drug tolerance while maintaining best possible structural integrity of ADAs. Results: Both ADA-bridging assays treated with MgCl2 showed improved drug tolerance and higher signal-to-blank values compared with overnight incubation or acid treatment. Conclusion: The use of MgCl2 treatment in ADA-bridging assays provides a sensitive, drug tolerant and easy-to-use alternative in cases where acid dissociation is not possible or unwanted.

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High salt compatible oxyanion receptors by dual ion imprinting

Chemical Science ◽

10.1039/c9sc06508c ◽

2020 ◽

Vol 11 (16) ◽

pp. 4246-4250 ◽

Cited By ~ 1

Author(s):

Sudhirkumar Shinde ◽

Mona Mansour ◽

Anil Incel ◽

Liliia Mavliutova ◽

Celina Wierzbicka ◽

...

Keyword(s):

Ionic Strength ◽

Ion Pair ◽

High Ionic Strength ◽

High Salt ◽

Ion Uptake ◽

Ion Imprinting

Imprinting of an ion-pair in presence of mutually compatible anion and cation host monomers leads to polymers showing enhanced ion uptake in competitive high ionic strength buffers.

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