Tuning the Interactions in Multiresponsive Complex Coacervate-Based Underwater Adhesives

In this work, we report the systematic investigation of a multiresponsive complex coacervate-based underwater adhesive, obtained by combining polyelectrolyte domains and thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) units. This material exhibits a transition from liquid to solid but, differently from most reactive glues, is completely held together by non-covalent interactions, i.e., electrostatic and hydrophobic. Because the solidification results in a kinetically trapped morphology, the final mechanical properties strongly depend on the preparation conditions and on the surrounding environment. A systematic study is performed to assess the effect of ionic strength and of PNIPAM content on the thermal, rheological and adhesive properties. This study enables the optimization of polymer composition and environmental conditions for this underwater adhesive system. The best performance with a work of adhesion of 6.5 J/m2 was found for the complex coacervates prepared at high ionic strength (0.75 M NaCl) and at an optimal PNIPAM content around 30% mol/mol. The high ionic strength enables injectability, while the hydrated PNIPAM domains provide additional dissipation, without softening the material so much that it becomes too weak to resist detaching stress.

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A Cross-Linker Free Enzyme Immobilization for Direct Bioelectrocatalysis Using Aqueous Phase Inversion of a High-Ionic-Strength, Liquid Complex Coacervate

ECS Meeting Abstracts ◽

10.1149/ma2019-02/44/2067 ◽

2019 ◽

Keyword(s):

Ionic Strength ◽

Enzyme Immobilization ◽

Aqueous Phase ◽

Phase Inversion ◽

High Ionic Strength ◽

Free Enzyme ◽

Complex Coacervate ◽

Cross Linker

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Hybrid Complex Coacervate

Polymers ◽

10.3390/polym12020320 ◽

2020 ◽

Vol 12 (2) ◽

pp. 320 ◽

Cited By ~ 1

Author(s):

Marco Dompé ◽

Francisco Javier Cedano-Serrano ◽

Mehdi Vahdati ◽

Dominique Hourdet ◽

Jasper van der Gucht ◽

...

Keyword(s):

Mechanical Properties ◽

Ionic Strength ◽

Solution Temperature ◽

Moderate Increase ◽

Adhesive Properties ◽

Underwater Adhesion ◽

Complex Coacervate ◽

Hybrid Complex ◽

Strength Gradient ◽

Oppositely Charged

Underwater adhesion represents a huge technological challenge as the presence of water compromises the performance of most commercially available adhesives. Inspired by natural organisms, we have designed an adhesive based on complex coacervation, a liquid–liquid phase separation phenomenon. A complex coacervate adhesive is formed by mixing oppositely charged polyelectrolytes bearing pendant thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) chains. The material fully sets underwater due to a change in the environmental conditions, namely temperature and ionic strength. In this work, we incorporate silica nanoparticles forming a hybrid complex coacervate and investigate the resulting mechanical properties. An enhancement of the mechanical properties is observed below the PNIPAM lower critical solution temperature (LCST): this is due to the formation of PNIPAM–silica junctions, which, after setting, contribute to a moderate increase in the moduli and in the adhesive properties only when applying an ionic strength gradient. By contrast, when raising the temperature above the LCST, the mechanical properties are dominated by the association of PNIPAM chains and the nanofiller incorporation leads to an increased heterogeneity with the formation of fracture planes at the interface between areas of different concentrations of nanoparticles, promoting earlier failure of the network—an unexpected and noteworthy consequence of this hybrid system.

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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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